* [PATCH 1/4] mm: add new mmgrab() helper
@ 2016-12-18 12:32 Vegard Nossum
2016-12-18 12:32 ` [PATCH 2/4] mm: add new mmget() helper Vegard Nossum
` (4 more replies)
0 siblings, 5 replies; 15+ messages in thread
From: Vegard Nossum @ 2016-12-18 12:32 UTC (permalink / raw)
To: Andrew Morton, Michal Hocko, linux-mm
Cc: Peter Zijlstra, Kirill A . Shutemov, linux-kernel, Vegard Nossum
Apart from adding the helper function itself, the rest of the kernel is
converted mechanically using:
git grep -l 'atomic_inc.*mm_count' | xargs sed -i 's/atomic_inc(&\(.*\)->mm_count);/mmgrab\(\1\);/'
git grep -l 'atomic_inc.*mm_count' | xargs sed -i 's/atomic_inc(&\(.*\)\.mm_count);/mmgrab\(\&\1\);/'
This is needed for a later patch that hooks into the helper, but might be
a worthwhile cleanup on its own.
(Michal Hocko provided most of the kerneldoc comment.)
Cc: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
---
arch/alpha/kernel/smp.c | 2 +-
arch/arc/kernel/smp.c | 2 +-
arch/arm/kernel/smp.c | 2 +-
arch/arm64/kernel/smp.c | 2 +-
arch/blackfin/mach-common/smp.c | 2 +-
arch/hexagon/kernel/smp.c | 2 +-
arch/ia64/kernel/setup.c | 2 +-
arch/m32r/kernel/setup.c | 2 +-
arch/metag/kernel/smp.c | 2 +-
arch/mips/kernel/traps.c | 2 +-
arch/mn10300/kernel/smp.c | 2 +-
arch/parisc/kernel/smp.c | 2 +-
arch/powerpc/kernel/smp.c | 2 +-
arch/s390/kernel/processor.c | 2 +-
arch/score/kernel/traps.c | 2 +-
arch/sh/kernel/smp.c | 2 +-
arch/sparc/kernel/leon_smp.c | 2 +-
arch/sparc/kernel/smp_64.c | 2 +-
arch/sparc/kernel/sun4d_smp.c | 2 +-
arch/sparc/kernel/sun4m_smp.c | 2 +-
arch/sparc/kernel/traps_32.c | 2 +-
arch/sparc/kernel/traps_64.c | 2 +-
arch/tile/kernel/smpboot.c | 2 +-
arch/x86/kernel/cpu/common.c | 4 ++--
arch/xtensa/kernel/smp.c | 2 +-
drivers/gpu/drm/amd/amdkfd/kfd_process.c | 2 +-
drivers/gpu/drm/i915/i915_gem_userptr.c | 2 +-
drivers/infiniband/hw/hfi1/file_ops.c | 2 +-
fs/proc/base.c | 4 ++--
fs/userfaultfd.c | 2 +-
include/linux/sched.h | 22 ++++++++++++++++++++++
kernel/exit.c | 2 +-
kernel/futex.c | 2 +-
kernel/sched/core.c | 4 ++--
mm/khugepaged.c | 2 +-
mm/ksm.c | 2 +-
mm/mmu_context.c | 2 +-
mm/mmu_notifier.c | 2 +-
mm/oom_kill.c | 4 ++--
virt/kvm/kvm_main.c | 2 +-
40 files changed, 65 insertions(+), 43 deletions(-)
diff --git a/arch/alpha/kernel/smp.c b/arch/alpha/kernel/smp.c
index 46bf263c3153..acb4b146a607 100644
--- a/arch/alpha/kernel/smp.c
+++ b/arch/alpha/kernel/smp.c
@@ -144,7 +144,7 @@ smp_callin(void)
alpha_mv.smp_callin();
/* All kernel threads share the same mm context. */
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
current->active_mm = &init_mm;
/* inform the notifiers about the new cpu */
diff --git a/arch/arc/kernel/smp.c b/arch/arc/kernel/smp.c
index 88674d972c9d..9cbc7aba3ede 100644
--- a/arch/arc/kernel/smp.c
+++ b/arch/arc/kernel/smp.c
@@ -125,7 +125,7 @@ void start_kernel_secondary(void)
setup_processor();
atomic_inc(&mm->mm_users);
- atomic_inc(&mm->mm_count);
+ mmgrab(mm);
current->active_mm = mm;
cpumask_set_cpu(cpu, mm_cpumask(mm));
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 7dd14e8395e6..c6514ce0fcbc 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -371,7 +371,7 @@ asmlinkage void secondary_start_kernel(void)
* reference and switch to it.
*/
cpu = smp_processor_id();
- atomic_inc(&mm->mm_count);
+ mmgrab(mm);
current->active_mm = mm;
cpumask_set_cpu(cpu, mm_cpumask(mm));
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index cb87234cfcf2..959e41196cba 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -222,7 +222,7 @@ asmlinkage void secondary_start_kernel(void)
* All kernel threads share the same mm context; grab a
* reference and switch to it.
*/
- atomic_inc(&mm->mm_count);
+ mmgrab(mm);
current->active_mm = mm;
/*
diff --git a/arch/blackfin/mach-common/smp.c b/arch/blackfin/mach-common/smp.c
index 23c4ef5f8bdc..bc5617ef7128 100644
--- a/arch/blackfin/mach-common/smp.c
+++ b/arch/blackfin/mach-common/smp.c
@@ -308,7 +308,7 @@ void secondary_start_kernel(void)
/* Attach the new idle task to the global mm. */
atomic_inc(&mm->mm_users);
- atomic_inc(&mm->mm_count);
+ mmgrab(mm);
current->active_mm = mm;
preempt_disable();
diff --git a/arch/hexagon/kernel/smp.c b/arch/hexagon/kernel/smp.c
index 983bae7d2665..c02a6455839e 100644
--- a/arch/hexagon/kernel/smp.c
+++ b/arch/hexagon/kernel/smp.c
@@ -162,7 +162,7 @@ void start_secondary(void)
);
/* Set the memory struct */
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
current->active_mm = &init_mm;
cpu = smp_processor_id();
diff --git a/arch/ia64/kernel/setup.c b/arch/ia64/kernel/setup.c
index 7ec7acc844c2..ecbff47b01f1 100644
--- a/arch/ia64/kernel/setup.c
+++ b/arch/ia64/kernel/setup.c
@@ -992,7 +992,7 @@ cpu_init (void)
*/
ia64_setreg(_IA64_REG_CR_DCR, ( IA64_DCR_DP | IA64_DCR_DK | IA64_DCR_DX | IA64_DCR_DR
| IA64_DCR_DA | IA64_DCR_DD | IA64_DCR_LC));
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
current->active_mm = &init_mm;
BUG_ON(current->mm);
diff --git a/arch/m32r/kernel/setup.c b/arch/m32r/kernel/setup.c
index 136c69f1fb8a..b18bc0bd6544 100644
--- a/arch/m32r/kernel/setup.c
+++ b/arch/m32r/kernel/setup.c
@@ -403,7 +403,7 @@ void __init cpu_init (void)
printk(KERN_INFO "Initializing CPU#%d\n", cpu_id);
/* Set up and load the per-CPU TSS and LDT */
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
current->active_mm = &init_mm;
if (current->mm)
BUG();
diff --git a/arch/metag/kernel/smp.c b/arch/metag/kernel/smp.c
index bad13232de51..af9cff547a19 100644
--- a/arch/metag/kernel/smp.c
+++ b/arch/metag/kernel/smp.c
@@ -345,7 +345,7 @@ asmlinkage void secondary_start_kernel(void)
* reference and switch to it.
*/
atomic_inc(&mm->mm_users);
- atomic_inc(&mm->mm_count);
+ mmgrab(mm);
current->active_mm = mm;
cpumask_set_cpu(cpu, mm_cpumask(mm));
enter_lazy_tlb(mm, current);
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 3905003dfe2b..e50b0e0ca44c 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -2177,7 +2177,7 @@ void per_cpu_trap_init(bool is_boot_cpu)
if (!cpu_data[cpu].asid_cache)
cpu_data[cpu].asid_cache = asid_first_version(cpu);
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
current->active_mm = &init_mm;
BUG_ON(current->mm);
enter_lazy_tlb(&init_mm, current);
diff --git a/arch/mn10300/kernel/smp.c b/arch/mn10300/kernel/smp.c
index 426173c4b0b9..e65b5cc2fa67 100644
--- a/arch/mn10300/kernel/smp.c
+++ b/arch/mn10300/kernel/smp.c
@@ -589,7 +589,7 @@ static void __init smp_cpu_init(void)
}
printk(KERN_INFO "Initializing CPU#%d\n", cpu_id);
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
current->active_mm = &init_mm;
BUG_ON(current->mm);
diff --git a/arch/parisc/kernel/smp.c b/arch/parisc/kernel/smp.c
index 75dab2871346..67b452b41ff6 100644
--- a/arch/parisc/kernel/smp.c
+++ b/arch/parisc/kernel/smp.c
@@ -279,7 +279,7 @@ smp_cpu_init(int cpunum)
set_cpu_online(cpunum, true);
/* Initialise the idle task for this CPU */
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
current->active_mm = &init_mm;
BUG_ON(current->mm);
enter_lazy_tlb(&init_mm, current);
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 9c6f3fd58059..42b82364c782 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -707,7 +707,7 @@ void start_secondary(void *unused)
unsigned int cpu = smp_processor_id();
int i, base;
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
current->active_mm = &init_mm;
smp_store_cpu_info(cpu);
diff --git a/arch/s390/kernel/processor.c b/arch/s390/kernel/processor.c
index 9e60ef144d03..b8fc689c9e2a 100644
--- a/arch/s390/kernel/processor.c
+++ b/arch/s390/kernel/processor.c
@@ -73,7 +73,7 @@ void cpu_init(void)
get_cpu_id(id);
if (machine_has_cpu_mhz)
update_cpu_mhz(NULL);
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
current->active_mm = &init_mm;
BUG_ON(current->mm);
enter_lazy_tlb(&init_mm, current);
diff --git a/arch/score/kernel/traps.c b/arch/score/kernel/traps.c
index 5cea1e750cec..6f6e5a39d147 100644
--- a/arch/score/kernel/traps.c
+++ b/arch/score/kernel/traps.c
@@ -336,7 +336,7 @@ void __init trap_init(void)
set_except_vector(18, handle_dbe);
flush_icache_range(DEBUG_VECTOR_BASE_ADDR, IRQ_VECTOR_BASE_ADDR);
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
current->active_mm = &init_mm;
cpu_cache_init();
}
diff --git a/arch/sh/kernel/smp.c b/arch/sh/kernel/smp.c
index 38e7860845db..ee379c699c08 100644
--- a/arch/sh/kernel/smp.c
+++ b/arch/sh/kernel/smp.c
@@ -178,7 +178,7 @@ asmlinkage void start_secondary(void)
struct mm_struct *mm = &init_mm;
enable_mmu();
- atomic_inc(&mm->mm_count);
+ mmgrab(mm);
atomic_inc(&mm->mm_users);
current->active_mm = mm;
#ifdef CONFIG_MMU
diff --git a/arch/sparc/kernel/leon_smp.c b/arch/sparc/kernel/leon_smp.c
index 71e16f2241c2..b99d33797e1d 100644
--- a/arch/sparc/kernel/leon_smp.c
+++ b/arch/sparc/kernel/leon_smp.c
@@ -93,7 +93,7 @@ void leon_cpu_pre_online(void *arg)
: "memory" /* paranoid */);
/* Attach to the address space of init_task. */
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
current->active_mm = &init_mm;
while (!cpumask_test_cpu(cpuid, &smp_commenced_mask))
diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c
index 8182f7caf5b1..c1d2bed22961 100644
--- a/arch/sparc/kernel/smp_64.c
+++ b/arch/sparc/kernel/smp_64.c
@@ -122,7 +122,7 @@ void smp_callin(void)
current_thread_info()->new_child = 0;
/* Attach to the address space of init_task. */
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
current->active_mm = &init_mm;
/* inform the notifiers about the new cpu */
diff --git a/arch/sparc/kernel/sun4d_smp.c b/arch/sparc/kernel/sun4d_smp.c
index 9d98e5002a09..7b55c50eabe5 100644
--- a/arch/sparc/kernel/sun4d_smp.c
+++ b/arch/sparc/kernel/sun4d_smp.c
@@ -93,7 +93,7 @@ void sun4d_cpu_pre_online(void *arg)
show_leds(cpuid);
/* Attach to the address space of init_task. */
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
current->active_mm = &init_mm;
local_ops->cache_all();
diff --git a/arch/sparc/kernel/sun4m_smp.c b/arch/sparc/kernel/sun4m_smp.c
index 278c40abce82..633c4cf6fdb0 100644
--- a/arch/sparc/kernel/sun4m_smp.c
+++ b/arch/sparc/kernel/sun4m_smp.c
@@ -59,7 +59,7 @@ void sun4m_cpu_pre_online(void *arg)
: "memory" /* paranoid */);
/* Attach to the address space of init_task. */
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
current->active_mm = &init_mm;
while (!cpumask_test_cpu(cpuid, &smp_commenced_mask))
diff --git a/arch/sparc/kernel/traps_32.c b/arch/sparc/kernel/traps_32.c
index 4f21df7d4f13..ecddac5a4c96 100644
--- a/arch/sparc/kernel/traps_32.c
+++ b/arch/sparc/kernel/traps_32.c
@@ -448,7 +448,7 @@ void trap_init(void)
thread_info_offsets_are_bolixed_pete();
/* Attach to the address space of init_task. */
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
current->active_mm = &init_mm;
/* NOTE: Other cpus have this done as they are started
diff --git a/arch/sparc/kernel/traps_64.c b/arch/sparc/kernel/traps_64.c
index 496fa926e1e0..83dd1331a30e 100644
--- a/arch/sparc/kernel/traps_64.c
+++ b/arch/sparc/kernel/traps_64.c
@@ -2764,6 +2764,6 @@ void __init trap_init(void)
/* Attach to the address space of init_task. On SMP we
* do this in smp.c:smp_callin for other cpus.
*/
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
current->active_mm = &init_mm;
}
diff --git a/arch/tile/kernel/smpboot.c b/arch/tile/kernel/smpboot.c
index 6c0abaacec33..53ce940a5016 100644
--- a/arch/tile/kernel/smpboot.c
+++ b/arch/tile/kernel/smpboot.c
@@ -160,7 +160,7 @@ static void start_secondary(void)
__this_cpu_write(current_asid, min_asid);
/* Set up this thread as another owner of the init_mm */
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
current->active_mm = &init_mm;
if (current->mm)
BUG();
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 729f92ba8224..5b88f78c40f5 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1498,7 +1498,7 @@ void cpu_init(void)
for (i = 0; i <= IO_BITMAP_LONGS; i++)
t->io_bitmap[i] = ~0UL;
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
me->active_mm = &init_mm;
BUG_ON(me->mm);
enter_lazy_tlb(&init_mm, me);
@@ -1549,7 +1549,7 @@ void cpu_init(void)
/*
* Set up and load the per-CPU TSS and LDT
*/
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
curr->active_mm = &init_mm;
BUG_ON(curr->mm);
enter_lazy_tlb(&init_mm, curr);
diff --git a/arch/xtensa/kernel/smp.c b/arch/xtensa/kernel/smp.c
index fc4ad21a5ed4..9bf5cea3bae4 100644
--- a/arch/xtensa/kernel/smp.c
+++ b/arch/xtensa/kernel/smp.c
@@ -136,7 +136,7 @@ void secondary_start_kernel(void)
/* All kernel threads share the same mm context. */
atomic_inc(&mm->mm_users);
- atomic_inc(&mm->mm_count);
+ mmgrab(mm);
current->active_mm = mm;
cpumask_set_cpu(cpu, mm_cpumask(mm));
enter_lazy_tlb(mm, current);
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_process.c b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
index ef7c8de7060e..ca5f2aa7232d 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_process.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
@@ -262,7 +262,7 @@ static void kfd_process_notifier_release(struct mmu_notifier *mn,
* and because the mmu_notifier_unregister function also drop
* mm_count we need to take an extra count here.
*/
- atomic_inc(&p->mm->mm_count);
+ mmgrab(p->mm);
mmu_notifier_unregister_no_release(&p->mmu_notifier, p->mm);
mmu_notifier_call_srcu(&p->rcu, &kfd_process_destroy_delayed);
}
diff --git a/drivers/gpu/drm/i915/i915_gem_userptr.c b/drivers/gpu/drm/i915/i915_gem_userptr.c
index d068af2ec3a3..1f27529cb48e 100644
--- a/drivers/gpu/drm/i915/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/i915_gem_userptr.c
@@ -334,7 +334,7 @@ i915_gem_userptr_init__mm_struct(struct drm_i915_gem_object *obj)
mm->i915 = to_i915(obj->base.dev);
mm->mm = current->mm;
- atomic_inc(¤t->mm->mm_count);
+ mmgrab(current->mm);
mm->mn = NULL;
diff --git a/drivers/infiniband/hw/hfi1/file_ops.c b/drivers/infiniband/hw/hfi1/file_ops.c
index bd786b7bd30b..2e1a6643a910 100644
--- a/drivers/infiniband/hw/hfi1/file_ops.c
+++ b/drivers/infiniband/hw/hfi1/file_ops.c
@@ -185,7 +185,7 @@ static int hfi1_file_open(struct inode *inode, struct file *fp)
if (fd) {
fd->rec_cpu_num = -1; /* no cpu affinity by default */
fd->mm = current->mm;
- atomic_inc(&fd->mm->mm_count);
+ mmgrab(fd->mm);
fp->private_data = fd;
} else {
fp->private_data = NULL;
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 5ea836362870..32f04999d930 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -798,7 +798,7 @@ struct mm_struct *proc_mem_open(struct inode *inode, unsigned int mode)
if (!IS_ERR_OR_NULL(mm)) {
/* ensure this mm_struct can't be freed */
- atomic_inc(&mm->mm_count);
+ mmgrab(mm);
/* but do not pin its memory */
mmput(mm);
}
@@ -1096,7 +1096,7 @@ static int __set_oom_adj(struct file *file, int oom_adj, bool legacy)
if (p) {
if (atomic_read(&p->mm->mm_users) > 1) {
mm = p->mm;
- atomic_inc(&mm->mm_count);
+ mmgrab(mm);
}
task_unlock(p);
}
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index d96e2f30084b..a02bbf5897e6 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -1306,7 +1306,7 @@ static struct file *userfaultfd_file_create(int flags)
ctx->released = false;
ctx->mm = current->mm;
/* prevent the mm struct to be freed */
- atomic_inc(&ctx->mm->mm_count);
+ mmgrab(ctx->mm);
file = anon_inode_getfile("[userfaultfd]", &userfaultfd_fops, ctx,
O_RDWR | (flags & UFFD_SHARED_FCNTL_FLAGS));
diff --git a/include/linux/sched.h b/include/linux/sched.h
index a440cf178191..6ce46220bda2 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2911,6 +2911,28 @@ static inline unsigned long sigsp(unsigned long sp, struct ksignal *ksig)
*/
extern struct mm_struct * mm_alloc(void);
+/**
+ * mmgrab() - Pin a &struct mm_struct.
+ * @mm: The &struct mm_struct to pin.
+ *
+ * Make sure that @mm will not get freed even after the owning task
+ * exits. This doesn't guarantee that the associated address space
+ * will still exist later on and mmget_not_zero() has to be used before
+ * accessing it.
+ *
+ * This is a preferred way to to pin @mm for a longer/unbounded amount
+ * of time.
+ *
+ * Use mmdrop() to release the reference acquired by mmgrab().
+ *
+ * See also <Documentation/vm/active_mm.txt> for an in-depth explanation
+ * of &mm_struct.mm_count vs &mm_struct.mm_users.
+ */
+static inline void mmgrab(struct mm_struct *mm)
+{
+ atomic_inc(&mm->mm_count);
+}
+
/* mmdrop drops the mm and the page tables */
extern void __mmdrop(struct mm_struct *);
static inline void mmdrop(struct mm_struct *mm)
diff --git a/kernel/exit.c b/kernel/exit.c
index aacff8e2aec0..a0bfdace6a07 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -509,7 +509,7 @@ static void exit_mm(struct task_struct *tsk)
__set_task_state(tsk, TASK_RUNNING);
down_read(&mm->mmap_sem);
}
- atomic_inc(&mm->mm_count);
+ mmgrab(mm);
BUG_ON(mm != tsk->active_mm);
/* more a memory barrier than a real lock */
task_lock(tsk);
diff --git a/kernel/futex.c b/kernel/futex.c
index 9246d9f593d1..cc84e6bd6a4d 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -338,7 +338,7 @@ static inline bool should_fail_futex(bool fshared)
static inline void futex_get_mm(union futex_key *key)
{
- atomic_inc(&key->private.mm->mm_count);
+ mmgrab(key->private.mm);
/*
* Ensure futex_get_mm() implies a full barrier such that
* get_futex_key() implies a full barrier. This is relied upon
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 966556ebdbb3..49d7076d93c3 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2878,7 +2878,7 @@ context_switch(struct rq *rq, struct task_struct *prev,
if (!mm) {
next->active_mm = oldmm;
- atomic_inc(&oldmm->mm_count);
+ mmgrab(oldmm);
enter_lazy_tlb(oldmm, next);
} else
switch_mm_irqs_off(oldmm, mm, next);
@@ -7686,7 +7686,7 @@ void __init sched_init(void)
/*
* The boot idle thread does lazy MMU switching as well:
*/
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
enter_lazy_tlb(&init_mm, current);
/*
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index e32389a97030..4cf3b3af6313 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -420,7 +420,7 @@ int __khugepaged_enter(struct mm_struct *mm)
list_add_tail(&mm_slot->mm_node, &khugepaged_scan.mm_head);
spin_unlock(&khugepaged_mm_lock);
- atomic_inc(&mm->mm_count);
+ mmgrab(mm);
if (wakeup)
wake_up_interruptible(&khugepaged_wait);
diff --git a/mm/ksm.c b/mm/ksm.c
index 9ae6011a41f8..5a49aad9d87b 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -1813,7 +1813,7 @@ int __ksm_enter(struct mm_struct *mm)
spin_unlock(&ksm_mmlist_lock);
set_bit(MMF_VM_MERGEABLE, &mm->flags);
- atomic_inc(&mm->mm_count);
+ mmgrab(mm);
if (needs_wakeup)
wake_up_interruptible(&ksm_thread_wait);
diff --git a/mm/mmu_context.c b/mm/mmu_context.c
index 6f4d27c5bb32..daf67bb02b4a 100644
--- a/mm/mmu_context.c
+++ b/mm/mmu_context.c
@@ -25,7 +25,7 @@ void use_mm(struct mm_struct *mm)
task_lock(tsk);
active_mm = tsk->active_mm;
if (active_mm != mm) {
- atomic_inc(&mm->mm_count);
+ mmgrab(mm);
tsk->active_mm = mm;
}
tsk->mm = mm;
diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c
index f4259e496f83..32bc9f2ff7eb 100644
--- a/mm/mmu_notifier.c
+++ b/mm/mmu_notifier.c
@@ -275,7 +275,7 @@ static int do_mmu_notifier_register(struct mmu_notifier *mn,
mm->mmu_notifier_mm = mmu_notifier_mm;
mmu_notifier_mm = NULL;
}
- atomic_inc(&mm->mm_count);
+ mmgrab(mm);
/*
* Serialize the update against mmu_notifier_unregister. A
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index ec9f11d4f094..ead093c6f2a6 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -660,7 +660,7 @@ static void mark_oom_victim(struct task_struct *tsk)
/* oom_mm is bound to the signal struct life time. */
if (!cmpxchg(&tsk->signal->oom_mm, NULL, mm))
- atomic_inc(&tsk->signal->oom_mm->mm_count);
+ mmgrab(tsk->signal->oom_mm);
/*
* Make sure that the task is woken up from uninterruptible sleep
@@ -877,7 +877,7 @@ static void oom_kill_process(struct oom_control *oc, const char *message)
/* Get a reference to safely compare mm after task_unlock(victim) */
mm = victim->mm;
- atomic_inc(&mm->mm_count);
+ mmgrab(mm);
/*
* We should send SIGKILL before setting TIF_MEMDIE in order to prevent
* the OOM victim from depleting the memory reserves from the user
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index de102cae7125..3a61b572fa2c 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -616,7 +616,7 @@ static struct kvm *kvm_create_vm(unsigned long type)
return ERR_PTR(-ENOMEM);
spin_lock_init(&kvm->mmu_lock);
- atomic_inc(¤t->mm->mm_count);
+ mmgrab(current->mm);
kvm->mm = current->mm;
kvm_eventfd_init(kvm);
mutex_init(&kvm->lock);
--
2.11.0.1.gaa10c3f
^ permalink raw reply related [flat|nested] 15+ messages in thread
* [PATCH 2/4] mm: add new mmget() helper
2016-12-18 12:32 [PATCH 1/4] mm: add new mmgrab() helper Vegard Nossum
@ 2016-12-18 12:32 ` Vegard Nossum
2017-01-09 23:18 ` Andrew Morton
2016-12-18 12:32 ` [PATCH 3/4] mm: use mmget_not_zero() helper Vegard Nossum
` (3 subsequent siblings)
4 siblings, 1 reply; 15+ messages in thread
From: Vegard Nossum @ 2016-12-18 12:32 UTC (permalink / raw)
To: Andrew Morton, Michal Hocko, linux-mm
Cc: Peter Zijlstra, Kirill A . Shutemov, linux-kernel, Vegard Nossum
Apart from adding the helper function itself, the rest of the kernel is
converted mechanically using:
git grep -l 'atomic_inc.*mm_users' | xargs sed -i 's/atomic_inc(&\(.*\)->mm_users);/mmget\(\1\);/'
git grep -l 'atomic_inc.*mm_users' | xargs sed -i 's/atomic_inc(&\(.*\)\.mm_users);/mmget\(\&\1\);/'
This is needed for a later patch that hooks into the helper, but might be
a worthwhile cleanup on its own.
(Michal Hocko provided most of the kerneldoc comment.)
Cc: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
---
arch/arc/kernel/smp.c | 2 +-
arch/blackfin/mach-common/smp.c | 2 +-
arch/frv/mm/mmu-context.c | 2 +-
arch/metag/kernel/smp.c | 2 +-
arch/sh/kernel/smp.c | 2 +-
arch/xtensa/kernel/smp.c | 2 +-
include/linux/sched.h | 21 +++++++++++++++++++++
kernel/fork.c | 4 ++--
mm/swapfile.c | 10 +++++-----
virt/kvm/async_pf.c | 2 +-
10 files changed, 35 insertions(+), 14 deletions(-)
diff --git a/arch/arc/kernel/smp.c b/arch/arc/kernel/smp.c
index 9cbc7aba3ede..eec70cb71db1 100644
--- a/arch/arc/kernel/smp.c
+++ b/arch/arc/kernel/smp.c
@@ -124,7 +124,7 @@ void start_kernel_secondary(void)
/* MMU, Caches, Vector Table, Interrupts etc */
setup_processor();
- atomic_inc(&mm->mm_users);
+ mmget(mm);
mmgrab(mm);
current->active_mm = mm;
cpumask_set_cpu(cpu, mm_cpumask(mm));
diff --git a/arch/blackfin/mach-common/smp.c b/arch/blackfin/mach-common/smp.c
index bc5617ef7128..a2e6db2ce811 100644
--- a/arch/blackfin/mach-common/smp.c
+++ b/arch/blackfin/mach-common/smp.c
@@ -307,7 +307,7 @@ void secondary_start_kernel(void)
local_irq_disable();
/* Attach the new idle task to the global mm. */
- atomic_inc(&mm->mm_users);
+ mmget(mm);
mmgrab(mm);
current->active_mm = mm;
diff --git a/arch/frv/mm/mmu-context.c b/arch/frv/mm/mmu-context.c
index 81757d55a5b5..3473bde77f56 100644
--- a/arch/frv/mm/mmu-context.c
+++ b/arch/frv/mm/mmu-context.c
@@ -188,7 +188,7 @@ int cxn_pin_by_pid(pid_t pid)
task_lock(tsk);
if (tsk->mm) {
mm = tsk->mm;
- atomic_inc(&mm->mm_users);
+ mmget(mm);
ret = 0;
}
task_unlock(tsk);
diff --git a/arch/metag/kernel/smp.c b/arch/metag/kernel/smp.c
index af9cff547a19..c622293254e4 100644
--- a/arch/metag/kernel/smp.c
+++ b/arch/metag/kernel/smp.c
@@ -344,7 +344,7 @@ asmlinkage void secondary_start_kernel(void)
* All kernel threads share the same mm context; grab a
* reference and switch to it.
*/
- atomic_inc(&mm->mm_users);
+ mmget(mm);
mmgrab(mm);
current->active_mm = mm;
cpumask_set_cpu(cpu, mm_cpumask(mm));
diff --git a/arch/sh/kernel/smp.c b/arch/sh/kernel/smp.c
index ee379c699c08..edc4769b047e 100644
--- a/arch/sh/kernel/smp.c
+++ b/arch/sh/kernel/smp.c
@@ -179,7 +179,7 @@ asmlinkage void start_secondary(void)
enable_mmu();
mmgrab(mm);
- atomic_inc(&mm->mm_users);
+ mmget(mm);
current->active_mm = mm;
#ifdef CONFIG_MMU
enter_lazy_tlb(mm, current);
diff --git a/arch/xtensa/kernel/smp.c b/arch/xtensa/kernel/smp.c
index 9bf5cea3bae4..fcea72019df7 100644
--- a/arch/xtensa/kernel/smp.c
+++ b/arch/xtensa/kernel/smp.c
@@ -135,7 +135,7 @@ void secondary_start_kernel(void)
/* All kernel threads share the same mm context. */
- atomic_inc(&mm->mm_users);
+ mmget(mm);
mmgrab(mm);
current->active_mm = mm;
cpumask_set_cpu(cpu, mm_cpumask(mm));
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 6ce46220bda2..9fc07aaf5c97 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2955,6 +2955,27 @@ static inline void mmdrop_async(struct mm_struct *mm)
}
}
+/**
+ * mmget() - Pin the address space associated with a &struct mm_struct.
+ * @mm: The address space to pin.
+ *
+ * Make sure that the address space of the given &struct mm_struct doesn't
+ * go away. This does not protect against parts of the address space being
+ * modified or freed, however.
+ *
+ * Never use this function to pin this address space for an
+ * unbounded/indefinite amount of time.
+ *
+ * Use mmput() to release the reference acquired by mmget().
+ *
+ * See also <Documentation/vm/active_mm.txt> for an in-depth explanation
+ * of &mm_struct.mm_count vs &mm_struct.mm_users.
+ */
+static inline void mmget(struct mm_struct *mm)
+{
+ atomic_inc(&mm->mm_users);
+}
+
static inline bool mmget_not_zero(struct mm_struct *mm)
{
return atomic_inc_not_zero(&mm->mm_users);
diff --git a/kernel/fork.c b/kernel/fork.c
index 869b8ccc00bf..0e2aaa1837b3 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -994,7 +994,7 @@ struct mm_struct *get_task_mm(struct task_struct *task)
if (task->flags & PF_KTHREAD)
mm = NULL;
else
- atomic_inc(&mm->mm_users);
+ mmget(mm);
}
task_unlock(task);
return mm;
@@ -1182,7 +1182,7 @@ static int copy_mm(unsigned long clone_flags, struct task_struct *tsk)
vmacache_flush(tsk);
if (clone_flags & CLONE_VM) {
- atomic_inc(&oldmm->mm_users);
+ mmget(oldmm);
mm = oldmm;
goto good_mm;
}
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 1c6e0321205d..914c31cc143c 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1401,7 +1401,7 @@ int try_to_unuse(unsigned int type, bool frontswap,
* that.
*/
start_mm = &init_mm;
- atomic_inc(&init_mm.mm_users);
+ mmget(&init_mm);
/*
* Keep on scanning until all entries have gone. Usually,
@@ -1450,7 +1450,7 @@ int try_to_unuse(unsigned int type, bool frontswap,
if (atomic_read(&start_mm->mm_users) == 1) {
mmput(start_mm);
start_mm = &init_mm;
- atomic_inc(&init_mm.mm_users);
+ mmget(&init_mm);
}
/*
@@ -1487,8 +1487,8 @@ int try_to_unuse(unsigned int type, bool frontswap,
struct mm_struct *prev_mm = start_mm;
struct mm_struct *mm;
- atomic_inc(&new_start_mm->mm_users);
- atomic_inc(&prev_mm->mm_users);
+ mmget(new_start_mm);
+ mmget(prev_mm);
spin_lock(&mmlist_lock);
while (swap_count(*swap_map) && !retval &&
(p = p->next) != &start_mm->mmlist) {
@@ -1511,7 +1511,7 @@ int try_to_unuse(unsigned int type, bool frontswap,
if (set_start_mm && *swap_map < swcount) {
mmput(new_start_mm);
- atomic_inc(&mm->mm_users);
+ mmget(mm);
new_start_mm = mm;
set_start_mm = 0;
}
diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c
index 3815e940fbea..2366177172f6 100644
--- a/virt/kvm/async_pf.c
+++ b/virt/kvm/async_pf.c
@@ -204,7 +204,7 @@ int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, unsigned long hva,
work->addr = hva;
work->arch = *arch;
work->mm = current->mm;
- atomic_inc(&work->mm->mm_users);
+ mmget(work->mm);
kvm_get_kvm(work->vcpu->kvm);
/* this can't really happen otherwise gfn_to_pfn_async
--
2.11.0.1.gaa10c3f
^ permalink raw reply related [flat|nested] 15+ messages in thread
* [PATCH 3/4] mm: use mmget_not_zero() helper
2016-12-18 12:32 [PATCH 1/4] mm: add new mmgrab() helper Vegard Nossum
2016-12-18 12:32 ` [PATCH 2/4] mm: add new mmget() helper Vegard Nossum
@ 2016-12-18 12:32 ` Vegard Nossum
2016-12-18 12:32 ` [PATCH 4/4] mm: clarify mm_struct.mm_{users,count} documentation Vegard Nossum
` (2 subsequent siblings)
4 siblings, 0 replies; 15+ messages in thread
From: Vegard Nossum @ 2016-12-18 12:32 UTC (permalink / raw)
To: Andrew Morton, Michal Hocko, linux-mm
Cc: Peter Zijlstra, Kirill A . Shutemov, linux-kernel, Vegard Nossum
We already have the helper, we can convert the rest of the kernel
mechanically using:
git grep -l 'atomic_inc_not_zero.*mm_users' | xargs sed -i 's/atomic_inc_not_zero(&\(.*\)->mm_users)/mmget_not_zero\(\1\)/'
This is needed for a later patch that hooks into the helper, but might be
a worthwhile cleanup on its own.
Cc: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
---
drivers/gpu/drm/i915/i915_gem_userptr.c | 2 +-
drivers/iommu/intel-svm.c | 2 +-
fs/proc/base.c | 4 ++--
fs/proc/task_mmu.c | 4 ++--
fs/proc/task_nommu.c | 2 +-
kernel/events/uprobes.c | 2 +-
mm/swapfile.c | 2 +-
7 files changed, 9 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem_userptr.c b/drivers/gpu/drm/i915/i915_gem_userptr.c
index 1f27529cb48e..89be48ed7c77 100644
--- a/drivers/gpu/drm/i915/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/i915_gem_userptr.c
@@ -507,7 +507,7 @@ __i915_gem_userptr_get_pages_worker(struct work_struct *_work)
flags |= FOLL_WRITE;
ret = -EFAULT;
- if (atomic_inc_not_zero(&mm->mm_users)) {
+ if (mmget_not_zero(mm)) {
down_read(&mm->mmap_sem);
while (pinned < npages) {
ret = get_user_pages_remote
diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
index cb72e0011310..51f2b228723f 100644
--- a/drivers/iommu/intel-svm.c
+++ b/drivers/iommu/intel-svm.c
@@ -579,7 +579,7 @@ static irqreturn_t prq_event_thread(int irq, void *d)
if (!svm->mm)
goto bad_req;
/* If the mm is already defunct, don't handle faults. */
- if (!atomic_inc_not_zero(&svm->mm->mm_users))
+ if (!mmget_not_zero(svm->mm))
goto bad_req;
down_read(&svm->mm->mmap_sem);
vma = find_extend_vma(svm->mm, address);
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 32f04999d930..ec7304f5117a 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -845,7 +845,7 @@ static ssize_t mem_rw(struct file *file, char __user *buf,
return -ENOMEM;
copied = 0;
- if (!atomic_inc_not_zero(&mm->mm_users))
+ if (!mmget_not_zero(mm))
goto free;
/* Maybe we should limit FOLL_FORCE to actual ptrace users? */
@@ -953,7 +953,7 @@ static ssize_t environ_read(struct file *file, char __user *buf,
return -ENOMEM;
ret = 0;
- if (!atomic_inc_not_zero(&mm->mm_users))
+ if (!mmget_not_zero(mm))
goto free;
down_read(&mm->mmap_sem);
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 958f32545064..6c07c7813b26 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -167,7 +167,7 @@ static void *m_start(struct seq_file *m, loff_t *ppos)
return ERR_PTR(-ESRCH);
mm = priv->mm;
- if (!mm || !atomic_inc_not_zero(&mm->mm_users))
+ if (!mm || !mmget_not_zero(mm))
return NULL;
down_read(&mm->mmap_sem);
@@ -1352,7 +1352,7 @@ static ssize_t pagemap_read(struct file *file, char __user *buf,
unsigned long end_vaddr;
int ret = 0, copied = 0;
- if (!mm || !atomic_inc_not_zero(&mm->mm_users))
+ if (!mm || !mmget_not_zero(mm))
goto out;
ret = -EINVAL;
diff --git a/fs/proc/task_nommu.c b/fs/proc/task_nommu.c
index 37175621e890..1ef97cfcf422 100644
--- a/fs/proc/task_nommu.c
+++ b/fs/proc/task_nommu.c
@@ -219,7 +219,7 @@ static void *m_start(struct seq_file *m, loff_t *pos)
return ERR_PTR(-ESRCH);
mm = priv->mm;
- if (!mm || !atomic_inc_not_zero(&mm->mm_users))
+ if (!mm || !mmget_not_zero(mm))
return NULL;
down_read(&mm->mmap_sem);
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 215871bda3a2..f164fe8ca5ff 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -741,7 +741,7 @@ build_map_info(struct address_space *mapping, loff_t offset, bool is_register)
continue;
}
- if (!atomic_inc_not_zero(&vma->vm_mm->mm_users))
+ if (!mmget_not_zero(vma->vm_mm))
continue;
info = prev;
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 914c31cc143c..5502feef0a4a 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1493,7 +1493,7 @@ int try_to_unuse(unsigned int type, bool frontswap,
while (swap_count(*swap_map) && !retval &&
(p = p->next) != &start_mm->mmlist) {
mm = list_entry(p, struct mm_struct, mmlist);
- if (!atomic_inc_not_zero(&mm->mm_users))
+ if (!mmget_not_zero(mm))
continue;
spin_unlock(&mmlist_lock);
mmput(prev_mm);
--
2.11.0.1.gaa10c3f
^ permalink raw reply related [flat|nested] 15+ messages in thread
* [PATCH 4/4] mm: clarify mm_struct.mm_{users,count} documentation
2016-12-18 12:32 [PATCH 1/4] mm: add new mmgrab() helper Vegard Nossum
2016-12-18 12:32 ` [PATCH 2/4] mm: add new mmget() helper Vegard Nossum
2016-12-18 12:32 ` [PATCH 3/4] mm: use mmget_not_zero() helper Vegard Nossum
@ 2016-12-18 12:32 ` Vegard Nossum
2016-12-19 13:15 ` Michal Hocko
2016-12-19 10:29 ` [PATCH 1/4] mm: add new mmgrab() helper Peter Zijlstra
2016-12-22 22:03 ` David Rientjes
4 siblings, 1 reply; 15+ messages in thread
From: Vegard Nossum @ 2016-12-18 12:32 UTC (permalink / raw)
To: Andrew Morton, Michal Hocko, linux-mm
Cc: Peter Zijlstra, Kirill A . Shutemov, linux-kernel, Vegard Nossum
Clarify documentation relating to mm_users and mm_count, and switch to
kernel-doc syntax.
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
---
include/linux/mm_types.h | 23 +++++++++++++++++++++--
1 file changed, 21 insertions(+), 2 deletions(-)
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 08d947fc4c59..316c3e1fc226 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -407,8 +407,27 @@ struct mm_struct {
unsigned long task_size; /* size of task vm space */
unsigned long highest_vm_end; /* highest vma end address */
pgd_t * pgd;
- atomic_t mm_users; /* How many users with user space? */
- atomic_t mm_count; /* How many references to "struct mm_struct" (users count as 1) */
+
+ /**
+ * @mm_users: The number of users including userspace.
+ *
+ * Use mmget()/mmget_not_zero()/mmput() to modify. When this drops
+ * to 0 (i.e. when the task exits and there are no other temporary
+ * reference holders), we also release a reference on @mm_count
+ * (which may then free the &struct mm_struct if @mm_count also
+ * drops to 0).
+ */
+ atomic_t mm_users;
+
+ /**
+ * @mm_count: The number of references to &struct mm_struct
+ * (@mm_users count as 1).
+ *
+ * Use mmgrab()/mmdrop() to modify. When this drops to 0, the
+ * &struct mm_struct is freed.
+ */
+ atomic_t mm_count;
+
atomic_long_t nr_ptes; /* PTE page table pages */
#if CONFIG_PGTABLE_LEVELS > 2
atomic_long_t nr_pmds; /* PMD page table pages */
--
2.11.0.1.gaa10c3f
^ permalink raw reply related [flat|nested] 15+ messages in thread
* Re: [PATCH 1/4] mm: add new mmgrab() helper
2016-12-18 12:32 [PATCH 1/4] mm: add new mmgrab() helper Vegard Nossum
` (2 preceding siblings ...)
2016-12-18 12:32 ` [PATCH 4/4] mm: clarify mm_struct.mm_{users,count} documentation Vegard Nossum
@ 2016-12-19 10:29 ` Peter Zijlstra
2016-12-22 22:03 ` David Rientjes
4 siblings, 0 replies; 15+ messages in thread
From: Peter Zijlstra @ 2016-12-19 10:29 UTC (permalink / raw)
To: Vegard Nossum
Cc: Andrew Morton, Michal Hocko, linux-mm, Kirill A . Shutemov, linux-kernel
For all 4,
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH 4/4] mm: clarify mm_struct.mm_{users,count} documentation
2016-12-18 12:32 ` [PATCH 4/4] mm: clarify mm_struct.mm_{users,count} documentation Vegard Nossum
@ 2016-12-19 13:15 ` Michal Hocko
0 siblings, 0 replies; 15+ messages in thread
From: Michal Hocko @ 2016-12-19 13:15 UTC (permalink / raw)
To: Vegard Nossum
Cc: Andrew Morton, linux-mm, Peter Zijlstra, Kirill A . Shutemov,
linux-kernel
On Sun 18-12-16 13:32:29, Vegard Nossum wrote:
> Clarify documentation relating to mm_users and mm_count, and switch to
> kernel-doc syntax.
Looks good to me.
> Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
> ---
> include/linux/mm_types.h | 23 +++++++++++++++++++++--
> 1 file changed, 21 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
> index 08d947fc4c59..316c3e1fc226 100644
> --- a/include/linux/mm_types.h
> +++ b/include/linux/mm_types.h
> @@ -407,8 +407,27 @@ struct mm_struct {
> unsigned long task_size; /* size of task vm space */
> unsigned long highest_vm_end; /* highest vma end address */
> pgd_t * pgd;
> - atomic_t mm_users; /* How many users with user space? */
> - atomic_t mm_count; /* How many references to "struct mm_struct" (users count as 1) */
> +
> + /**
> + * @mm_users: The number of users including userspace.
> + *
> + * Use mmget()/mmget_not_zero()/mmput() to modify. When this drops
> + * to 0 (i.e. when the task exits and there are no other temporary
> + * reference holders), we also release a reference on @mm_count
> + * (which may then free the &struct mm_struct if @mm_count also
> + * drops to 0).
> + */
> + atomic_t mm_users;
> +
> + /**
> + * @mm_count: The number of references to &struct mm_struct
> + * (@mm_users count as 1).
> + *
> + * Use mmgrab()/mmdrop() to modify. When this drops to 0, the
> + * &struct mm_struct is freed.
> + */
> + atomic_t mm_count;
> +
> atomic_long_t nr_ptes; /* PTE page table pages */
> #if CONFIG_PGTABLE_LEVELS > 2
> atomic_long_t nr_pmds; /* PMD page table pages */
> --
> 2.11.0.1.gaa10c3f
>
--
Michal Hocko
SUSE Labs
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH 1/4] mm: add new mmgrab() helper
2016-12-18 12:32 [PATCH 1/4] mm: add new mmgrab() helper Vegard Nossum
` (3 preceding siblings ...)
2016-12-19 10:29 ` [PATCH 1/4] mm: add new mmgrab() helper Peter Zijlstra
@ 2016-12-22 22:03 ` David Rientjes
4 siblings, 0 replies; 15+ messages in thread
From: David Rientjes @ 2016-12-22 22:03 UTC (permalink / raw)
To: Vegard Nossum
Cc: Andrew Morton, Michal Hocko, linux-mm, Peter Zijlstra,
Kirill A . Shutemov, linux-kernel
On Sun, 18 Dec 2016, Vegard Nossum wrote:
> Apart from adding the helper function itself, the rest of the kernel is
> converted mechanically using:
>
> git grep -l 'atomic_inc.*mm_count' | xargs sed -i 's/atomic_inc(&\(.*\)->mm_count);/mmgrab\(\1\);/'
> git grep -l 'atomic_inc.*mm_count' | xargs sed -i 's/atomic_inc(&\(.*\)\.mm_count);/mmgrab\(\&\1\);/'
>
> This is needed for a later patch that hooks into the helper, but might be
> a worthwhile cleanup on its own.
>
> (Michal Hocko provided most of the kerneldoc comment.)
>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Acked-by: Michal Hocko <mhocko@suse.com>
> Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Acked-by: David Rientjes <rientjes@google.com>
for the series
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH 2/4] mm: add new mmget() helper
2016-12-18 12:32 ` [PATCH 2/4] mm: add new mmget() helper Vegard Nossum
@ 2017-01-09 23:18 ` Andrew Morton
0 siblings, 0 replies; 15+ messages in thread
From: Andrew Morton @ 2017-01-09 23:18 UTC (permalink / raw)
To: Vegard Nossum
Cc: Michal Hocko, linux-mm, Peter Zijlstra, Kirill A . Shutemov,
linux-kernel
On Sun, 18 Dec 2016 13:32:27 +0100 Vegard Nossum <vegard.nossum@oracle.com> wrote:
> Apart from adding the helper function itself, the rest of the kernel is
> converted mechanically using:
>
> git grep -l 'atomic_inc.*mm_users' | xargs sed -i 's/atomic_inc(&\(.*\)->mm_users);/mmget\(\1\);/'
> git grep -l 'atomic_inc.*mm_users' | xargs sed -i 's/atomic_inc(&\(.*\)\.mm_users);/mmget\(\&\1\);/'
>
> This is needed for a later patch that hooks into the helper, but might be
> a worthwhile cleanup on its own.
>
> ...
>
mmgrap() and mmget() naming is really quite confusing.
> --- a/arch/arc/kernel/smp.c
> +++ b/arch/arc/kernel/smp.c
> @@ -124,7 +124,7 @@ void start_kernel_secondary(void)
> /* MMU, Caches, Vector Table, Interrupts etc */
> setup_processor();
>
> - atomic_inc(&mm->mm_users);
> + mmget(mm);
I wonder if mmuse() would be a bit clearer than mmget(). Although that
sounds like use_mm().
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH 1/4] mm: add new mmgrab() helper
2016-12-16 9:56 ` Peter Zijlstra
2016-12-16 10:19 ` Kirill A. Shutemov
@ 2016-12-16 11:14 ` Vegard Nossum
1 sibling, 0 replies; 15+ messages in thread
From: Vegard Nossum @ 2016-12-16 11:14 UTC (permalink / raw)
To: Peter Zijlstra
Cc: linux-mm, linux-kernel, Rik van Riel, Matthew Wilcox,
Andrew Morton, Michal Hocko, Al Viro, Ingo Molnar,
Linus Torvalds
On 12/16/2016 10:56 AM, Peter Zijlstra wrote:
> On Fri, Dec 16, 2016 at 09:21:59AM +0100, Vegard Nossum wrote:
>> Apart from adding the helper function itself, the rest of the kernel is
>> converted mechanically using:
>>
>> git grep -l 'atomic_inc.*mm_count' | xargs sed -i 's/atomic_inc(&\(.*\)->mm_count);/mmgrab\(\1\);/'
>> git grep -l 'atomic_inc.*mm_count' | xargs sed -i 's/atomic_inc(&\(.*\)\.mm_count);/mmgrab\(\&\1\);/'
>>
>> This is needed for a later patch that hooks into the helper, but might be
>> a worthwhile cleanup on its own.
>
> Given the desire to replace all refcounting with a specific refcount
> type, this seems to make sense.
>
> FYI: http://www.openwall.com/lists/kernel-hardening/2016/12/07/8
If we're going that way eventually (replacing all reference counting
things with a generic interface), I wonder if we shouldn't consider a
generic mechanism for reference counting debugging too.
We could wrap all the 'type *' + 'type_ref' occurrences in a struct, so
that with debugging it boils down to just a pointer (like we have now):
struct ref {
void *ptr;
#ifdef CONFIG_REF_DEBUG
/* list_entry, pid, stacktrace, etc. */
#endif
};
Instead of calling refcount_inc() in most of the kernel code, that would
be considered a low-level detail and you'd have the main interface be
something like:
void ref_acquire(refcount_t *count, struct ref *old, struct ref *new)
{
refcount_inc(&count);
new->ptr = old->ptr;
#ifdef CONFIG_REF_DEBUG
/* extra code for debugging case */
#endif
}
So if you had old code that did (for example):
struct task_struct {
struct mm_struct *mm;
...
};
int proc_pid_cmdline_read(struct task_struct *task)
{
struct mm_struct *mm;
task_lock(task);
mm = task->mm;
atomic_inc(&mm->mm_users);
task_unlock(task);
...
mmput(mm);
}
you'd instead have:
struct task_struct {
struct ref mm;
};
int proc_pid_cmdline_read(struct task_struct *task)
{
REF(mm);
task_lock(task);
ref_acquire(&mm->mm_users, &task->mm, &mm)
task_unlock(task);
...
ref_release(&mm->mm_users, &mm);
}
Of course you'd define a 'struct ref' per type using a macro or
something to keep it type safe (maybe even wrap the counter itself in
there, e.g. mm_users in the example above, so you wouldn't have to pass
it explicitly).
Functions that don't touch reference counts (because the caller holds
one) can just take a plain pointer as usual.
In the example above, you could also have ref_release() set mm->ptr =
NULL; as the pointer should not be considered usable after it has been
released anyway for added safety/debugability.
Best of both worlds?
Vegard
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH 1/4] mm: add new mmgrab() helper
2016-12-16 10:20 ` Vegard Nossum
@ 2016-12-16 10:36 ` Michal Hocko
0 siblings, 0 replies; 15+ messages in thread
From: Michal Hocko @ 2016-12-16 10:36 UTC (permalink / raw)
To: Vegard Nossum
Cc: Kirill A. Shutemov, Peter Zijlstra, linux-mm, linux-kernel,
Rik van Riel, Matthew Wilcox, Andrew Morton, Al Viro,
Ingo Molnar, Linus Torvalds
On Fri 16-12-16 11:20:40, Vegard Nossum wrote:
> On 12/16/2016 11:19 AM, Kirill A. Shutemov wrote:
> > On Fri, Dec 16, 2016 at 10:56:24AM +0100, Peter Zijlstra wrote:
> > > But I must say mmget() vs mmgrab() is a wee bit confusing.
> >
> > mm_count vs mm_users is not very clear too. :)
> >
>
> I was about to say, I'm not sure it's much better than mmput() vs
> mmdrop() or mm_users vs mm_count either, although the way I rationalised
> it was the 3 vs 4 letters:
>
> mmget() -- mmgrab()
> mmput() -- mmdrop()
> ^^^ 3 ^^^^ 4
get -> put
grab -> drop
makes sense to me... No idea about a much more clear name.
--
Michal Hocko
SUSE Labs
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH 1/4] mm: add new mmgrab() helper
2016-12-16 10:19 ` Kirill A. Shutemov
@ 2016-12-16 10:20 ` Vegard Nossum
2016-12-16 10:36 ` Michal Hocko
0 siblings, 1 reply; 15+ messages in thread
From: Vegard Nossum @ 2016-12-16 10:20 UTC (permalink / raw)
To: Kirill A. Shutemov, Peter Zijlstra
Cc: linux-mm, linux-kernel, Rik van Riel, Matthew Wilcox,
Andrew Morton, Michal Hocko, Al Viro, Ingo Molnar,
Linus Torvalds
On 12/16/2016 11:19 AM, Kirill A. Shutemov wrote:
> On Fri, Dec 16, 2016 at 10:56:24AM +0100, Peter Zijlstra wrote:
>> But I must say mmget() vs mmgrab() is a wee bit confusing.
>
> mm_count vs mm_users is not very clear too. :)
>
I was about to say, I'm not sure it's much better than mmput() vs
mmdrop() or mm_users vs mm_count either, although the way I rationalised
it was the 3 vs 4 letters:
mmget() -- mmgrab()
mmput() -- mmdrop()
^^^ 3 ^^^^ 4
Vegard
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH 1/4] mm: add new mmgrab() helper
2016-12-16 9:56 ` Peter Zijlstra
@ 2016-12-16 10:19 ` Kirill A. Shutemov
2016-12-16 10:20 ` Vegard Nossum
2016-12-16 11:14 ` Vegard Nossum
1 sibling, 1 reply; 15+ messages in thread
From: Kirill A. Shutemov @ 2016-12-16 10:19 UTC (permalink / raw)
To: Peter Zijlstra
Cc: Vegard Nossum, linux-mm, linux-kernel, Rik van Riel,
Matthew Wilcox, Andrew Morton, Michal Hocko, Al Viro,
Ingo Molnar, Linus Torvalds
On Fri, Dec 16, 2016 at 10:56:24AM +0100, Peter Zijlstra wrote:
> But I must say mmget() vs mmgrab() is a wee bit confusing.
mm_count vs mm_users is not very clear too. :)
--
Kirill A. Shutemov
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH 1/4] mm: add new mmgrab() helper
2016-12-16 8:21 Vegard Nossum
2016-12-16 9:14 ` Michal Hocko
@ 2016-12-16 9:56 ` Peter Zijlstra
2016-12-16 10:19 ` Kirill A. Shutemov
2016-12-16 11:14 ` Vegard Nossum
1 sibling, 2 replies; 15+ messages in thread
From: Peter Zijlstra @ 2016-12-16 9:56 UTC (permalink / raw)
To: Vegard Nossum
Cc: linux-mm, linux-kernel, Rik van Riel, Matthew Wilcox,
Andrew Morton, Michal Hocko, Al Viro, Ingo Molnar,
Linus Torvalds
On Fri, Dec 16, 2016 at 09:21:59AM +0100, Vegard Nossum wrote:
> Apart from adding the helper function itself, the rest of the kernel is
> converted mechanically using:
>
> git grep -l 'atomic_inc.*mm_count' | xargs sed -i 's/atomic_inc(&\(.*\)->mm_count);/mmgrab\(\1\);/'
> git grep -l 'atomic_inc.*mm_count' | xargs sed -i 's/atomic_inc(&\(.*\)\.mm_count);/mmgrab\(\&\1\);/'
>
> This is needed for a later patch that hooks into the helper, but might be
> a worthwhile cleanup on its own.
Given the desire to replace all refcounting with a specific refcount
type, this seems to make sense.
FYI: http://www.openwall.com/lists/kernel-hardening/2016/12/07/8
But I must say mmget() vs mmgrab() is a wee bit confusing.
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH 1/4] mm: add new mmgrab() helper
2016-12-16 8:21 Vegard Nossum
@ 2016-12-16 9:14 ` Michal Hocko
2016-12-16 9:56 ` Peter Zijlstra
1 sibling, 0 replies; 15+ messages in thread
From: Michal Hocko @ 2016-12-16 9:14 UTC (permalink / raw)
To: Vegard Nossum
Cc: linux-mm, linux-kernel, Rik van Riel, Matthew Wilcox,
Peter Zijlstra, Andrew Morton, Al Viro, Ingo Molnar,
Linus Torvalds
On Fri 16-12-16 09:21:59, Vegard Nossum wrote:
> Apart from adding the helper function itself, the rest of the kernel is
> converted mechanically using:
>
> git grep -l 'atomic_inc.*mm_count' | xargs sed -i 's/atomic_inc(&\(.*\)->mm_count);/mmgrab\(\1\);/'
> git grep -l 'atomic_inc.*mm_count' | xargs sed -i 's/atomic_inc(&\(.*\)\.mm_count);/mmgrab\(\&\1\);/'
>
> This is needed for a later patch that hooks into the helper, but might be
> a worthwhile cleanup on its own.
>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Michal Hocko <mhocko@suse.com>
> Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Yes this make sense to me. I usually do not like wrappers around simple
atomic operations but the api will be more symmetric (and cscope will
work nicer as a bonus).
While you are there a comment explaining where mmgrab should be used
would be nice
/**
* mmgrab: pins the mm_struct
*
* Make sure that the mm struct will not get freed even after the owner
* task exits. This doesn't guarantee that the associated address space
* will still exist later on and mmget_not_zero has to be used before
* accessing it.
*
* This is a preferred way to to pin the mm struct for longer/unbound
* time.
*/
or something along those lines.
Anyway
Acked-by: Michal Hocko <mhocko@suse.com>
> ---
> arch/alpha/kernel/smp.c | 2 +-
> arch/arc/kernel/smp.c | 2 +-
> arch/arm/kernel/smp.c | 2 +-
> arch/arm64/kernel/smp.c | 2 +-
> arch/blackfin/mach-common/smp.c | 2 +-
> arch/hexagon/kernel/smp.c | 2 +-
> arch/ia64/kernel/setup.c | 2 +-
> arch/m32r/kernel/setup.c | 2 +-
> arch/metag/kernel/smp.c | 2 +-
> arch/mips/kernel/traps.c | 2 +-
> arch/mn10300/kernel/smp.c | 2 +-
> arch/parisc/kernel/smp.c | 2 +-
> arch/powerpc/kernel/smp.c | 2 +-
> arch/s390/kernel/processor.c | 2 +-
> arch/score/kernel/traps.c | 2 +-
> arch/sh/kernel/smp.c | 2 +-
> arch/sparc/kernel/leon_smp.c | 2 +-
> arch/sparc/kernel/smp_64.c | 2 +-
> arch/sparc/kernel/sun4d_smp.c | 2 +-
> arch/sparc/kernel/sun4m_smp.c | 2 +-
> arch/sparc/kernel/traps_32.c | 2 +-
> arch/sparc/kernel/traps_64.c | 2 +-
> arch/tile/kernel/smpboot.c | 2 +-
> arch/x86/kernel/cpu/common.c | 4 ++--
> arch/xtensa/kernel/smp.c | 2 +-
> drivers/gpu/drm/amd/amdkfd/kfd_process.c | 2 +-
> drivers/gpu/drm/i915/i915_gem_userptr.c | 2 +-
> drivers/infiniband/hw/hfi1/file_ops.c | 2 +-
> fs/proc/base.c | 4 ++--
> fs/userfaultfd.c | 2 +-
> include/linux/sched.h | 5 +++++
> kernel/exit.c | 2 +-
> kernel/futex.c | 2 +-
> kernel/sched/core.c | 4 ++--
> mm/khugepaged.c | 2 +-
> mm/ksm.c | 2 +-
> mm/mmu_context.c | 2 +-
> mm/mmu_notifier.c | 2 +-
> mm/oom_kill.c | 4 ++--
> virt/kvm/kvm_main.c | 2 +-
> 40 files changed, 48 insertions(+), 43 deletions(-)
>
> diff --git a/arch/alpha/kernel/smp.c b/arch/alpha/kernel/smp.c
> index 46bf263c3153..acb4b146a607 100644
> --- a/arch/alpha/kernel/smp.c
> +++ b/arch/alpha/kernel/smp.c
> @@ -144,7 +144,7 @@ smp_callin(void)
> alpha_mv.smp_callin();
>
> /* All kernel threads share the same mm context. */
> - atomic_inc(&init_mm.mm_count);
> + mmgrab(&init_mm);
> current->active_mm = &init_mm;
>
> /* inform the notifiers about the new cpu */
> diff --git a/arch/arc/kernel/smp.c b/arch/arc/kernel/smp.c
> index 88674d972c9d..9cbc7aba3ede 100644
> --- a/arch/arc/kernel/smp.c
> +++ b/arch/arc/kernel/smp.c
> @@ -125,7 +125,7 @@ void start_kernel_secondary(void)
> setup_processor();
>
> atomic_inc(&mm->mm_users);
> - atomic_inc(&mm->mm_count);
> + mmgrab(mm);
> current->active_mm = mm;
> cpumask_set_cpu(cpu, mm_cpumask(mm));
>
> diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
> index 7dd14e8395e6..c6514ce0fcbc 100644
> --- a/arch/arm/kernel/smp.c
> +++ b/arch/arm/kernel/smp.c
> @@ -371,7 +371,7 @@ asmlinkage void secondary_start_kernel(void)
> * reference and switch to it.
> */
> cpu = smp_processor_id();
> - atomic_inc(&mm->mm_count);
> + mmgrab(mm);
> current->active_mm = mm;
> cpumask_set_cpu(cpu, mm_cpumask(mm));
>
> diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
> index 8507703dabe4..61969ea29654 100644
> --- a/arch/arm64/kernel/smp.c
> +++ b/arch/arm64/kernel/smp.c
> @@ -214,7 +214,7 @@ asmlinkage void secondary_start_kernel(void)
> * All kernel threads share the same mm context; grab a
> * reference and switch to it.
> */
> - atomic_inc(&mm->mm_count);
> + mmgrab(mm);
> current->active_mm = mm;
>
> set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
> diff --git a/arch/blackfin/mach-common/smp.c b/arch/blackfin/mach-common/smp.c
> index 23c4ef5f8bdc..bc5617ef7128 100644
> --- a/arch/blackfin/mach-common/smp.c
> +++ b/arch/blackfin/mach-common/smp.c
> @@ -308,7 +308,7 @@ void secondary_start_kernel(void)
>
> /* Attach the new idle task to the global mm. */
> atomic_inc(&mm->mm_users);
> - atomic_inc(&mm->mm_count);
> + mmgrab(mm);
> current->active_mm = mm;
>
> preempt_disable();
> diff --git a/arch/hexagon/kernel/smp.c b/arch/hexagon/kernel/smp.c
> index 983bae7d2665..c02a6455839e 100644
> --- a/arch/hexagon/kernel/smp.c
> +++ b/arch/hexagon/kernel/smp.c
> @@ -162,7 +162,7 @@ void start_secondary(void)
> );
>
> /* Set the memory struct */
> - atomic_inc(&init_mm.mm_count);
> + mmgrab(&init_mm);
> current->active_mm = &init_mm;
>
> cpu = smp_processor_id();
> diff --git a/arch/ia64/kernel/setup.c b/arch/ia64/kernel/setup.c
> index 7ec7acc844c2..ecbff47b01f1 100644
> --- a/arch/ia64/kernel/setup.c
> +++ b/arch/ia64/kernel/setup.c
> @@ -992,7 +992,7 @@ cpu_init (void)
> */
> ia64_setreg(_IA64_REG_CR_DCR, ( IA64_DCR_DP | IA64_DCR_DK | IA64_DCR_DX | IA64_DCR_DR
> | IA64_DCR_DA | IA64_DCR_DD | IA64_DCR_LC));
> - atomic_inc(&init_mm.mm_count);
> + mmgrab(&init_mm);
> current->active_mm = &init_mm;
> BUG_ON(current->mm);
>
> diff --git a/arch/m32r/kernel/setup.c b/arch/m32r/kernel/setup.c
> index 136c69f1fb8a..b18bc0bd6544 100644
> --- a/arch/m32r/kernel/setup.c
> +++ b/arch/m32r/kernel/setup.c
> @@ -403,7 +403,7 @@ void __init cpu_init (void)
> printk(KERN_INFO "Initializing CPU#%d\n", cpu_id);
>
> /* Set up and load the per-CPU TSS and LDT */
> - atomic_inc(&init_mm.mm_count);
> + mmgrab(&init_mm);
> current->active_mm = &init_mm;
> if (current->mm)
> BUG();
> diff --git a/arch/metag/kernel/smp.c b/arch/metag/kernel/smp.c
> index bad13232de51..af9cff547a19 100644
> --- a/arch/metag/kernel/smp.c
> +++ b/arch/metag/kernel/smp.c
> @@ -345,7 +345,7 @@ asmlinkage void secondary_start_kernel(void)
> * reference and switch to it.
> */
> atomic_inc(&mm->mm_users);
> - atomic_inc(&mm->mm_count);
> + mmgrab(mm);
> current->active_mm = mm;
> cpumask_set_cpu(cpu, mm_cpumask(mm));
> enter_lazy_tlb(mm, current);
> diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
> index 3905003dfe2b..e50b0e0ca44c 100644
> --- a/arch/mips/kernel/traps.c
> +++ b/arch/mips/kernel/traps.c
> @@ -2177,7 +2177,7 @@ void per_cpu_trap_init(bool is_boot_cpu)
> if (!cpu_data[cpu].asid_cache)
> cpu_data[cpu].asid_cache = asid_first_version(cpu);
>
> - atomic_inc(&init_mm.mm_count);
> + mmgrab(&init_mm);
> current->active_mm = &init_mm;
> BUG_ON(current->mm);
> enter_lazy_tlb(&init_mm, current);
> diff --git a/arch/mn10300/kernel/smp.c b/arch/mn10300/kernel/smp.c
> index 426173c4b0b9..e65b5cc2fa67 100644
> --- a/arch/mn10300/kernel/smp.c
> +++ b/arch/mn10300/kernel/smp.c
> @@ -589,7 +589,7 @@ static void __init smp_cpu_init(void)
> }
> printk(KERN_INFO "Initializing CPU#%d\n", cpu_id);
>
> - atomic_inc(&init_mm.mm_count);
> + mmgrab(&init_mm);
> current->active_mm = &init_mm;
> BUG_ON(current->mm);
>
> diff --git a/arch/parisc/kernel/smp.c b/arch/parisc/kernel/smp.c
> index 75dab2871346..67b452b41ff6 100644
> --- a/arch/parisc/kernel/smp.c
> +++ b/arch/parisc/kernel/smp.c
> @@ -279,7 +279,7 @@ smp_cpu_init(int cpunum)
> set_cpu_online(cpunum, true);
>
> /* Initialise the idle task for this CPU */
> - atomic_inc(&init_mm.mm_count);
> + mmgrab(&init_mm);
> current->active_mm = &init_mm;
> BUG_ON(current->mm);
> enter_lazy_tlb(&init_mm, current);
> diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
> index 9c6f3fd58059..42b82364c782 100644
> --- a/arch/powerpc/kernel/smp.c
> +++ b/arch/powerpc/kernel/smp.c
> @@ -707,7 +707,7 @@ void start_secondary(void *unused)
> unsigned int cpu = smp_processor_id();
> int i, base;
>
> - atomic_inc(&init_mm.mm_count);
> + mmgrab(&init_mm);
> current->active_mm = &init_mm;
>
> smp_store_cpu_info(cpu);
> diff --git a/arch/s390/kernel/processor.c b/arch/s390/kernel/processor.c
> index 81d0808085e6..ec9bc100895c 100644
> --- a/arch/s390/kernel/processor.c
> +++ b/arch/s390/kernel/processor.c
> @@ -73,7 +73,7 @@ void cpu_init(void)
> get_cpu_id(id);
> if (machine_has_cpu_mhz)
> update_cpu_mhz(NULL);
> - atomic_inc(&init_mm.mm_count);
> + mmgrab(&init_mm);
> current->active_mm = &init_mm;
> BUG_ON(current->mm);
> enter_lazy_tlb(&init_mm, current);
> diff --git a/arch/score/kernel/traps.c b/arch/score/kernel/traps.c
> index 5cea1e750cec..6f6e5a39d147 100644
> --- a/arch/score/kernel/traps.c
> +++ b/arch/score/kernel/traps.c
> @@ -336,7 +336,7 @@ void __init trap_init(void)
> set_except_vector(18, handle_dbe);
> flush_icache_range(DEBUG_VECTOR_BASE_ADDR, IRQ_VECTOR_BASE_ADDR);
>
> - atomic_inc(&init_mm.mm_count);
> + mmgrab(&init_mm);
> current->active_mm = &init_mm;
> cpu_cache_init();
> }
> diff --git a/arch/sh/kernel/smp.c b/arch/sh/kernel/smp.c
> index 38e7860845db..ee379c699c08 100644
> --- a/arch/sh/kernel/smp.c
> +++ b/arch/sh/kernel/smp.c
> @@ -178,7 +178,7 @@ asmlinkage void start_secondary(void)
> struct mm_struct *mm = &init_mm;
>
> enable_mmu();
> - atomic_inc(&mm->mm_count);
> + mmgrab(mm);
> atomic_inc(&mm->mm_users);
> current->active_mm = mm;
> #ifdef CONFIG_MMU
> diff --git a/arch/sparc/kernel/leon_smp.c b/arch/sparc/kernel/leon_smp.c
> index 71e16f2241c2..b99d33797e1d 100644
> --- a/arch/sparc/kernel/leon_smp.c
> +++ b/arch/sparc/kernel/leon_smp.c
> @@ -93,7 +93,7 @@ void leon_cpu_pre_online(void *arg)
> : "memory" /* paranoid */);
>
> /* Attach to the address space of init_task. */
> - atomic_inc(&init_mm.mm_count);
> + mmgrab(&init_mm);
> current->active_mm = &init_mm;
>
> while (!cpumask_test_cpu(cpuid, &smp_commenced_mask))
> diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c
> index 8182f7caf5b1..c1d2bed22961 100644
> --- a/arch/sparc/kernel/smp_64.c
> +++ b/arch/sparc/kernel/smp_64.c
> @@ -122,7 +122,7 @@ void smp_callin(void)
> current_thread_info()->new_child = 0;
>
> /* Attach to the address space of init_task. */
> - atomic_inc(&init_mm.mm_count);
> + mmgrab(&init_mm);
> current->active_mm = &init_mm;
>
> /* inform the notifiers about the new cpu */
> diff --git a/arch/sparc/kernel/sun4d_smp.c b/arch/sparc/kernel/sun4d_smp.c
> index 9d98e5002a09..7b55c50eabe5 100644
> --- a/arch/sparc/kernel/sun4d_smp.c
> +++ b/arch/sparc/kernel/sun4d_smp.c
> @@ -93,7 +93,7 @@ void sun4d_cpu_pre_online(void *arg)
> show_leds(cpuid);
>
> /* Attach to the address space of init_task. */
> - atomic_inc(&init_mm.mm_count);
> + mmgrab(&init_mm);
> current->active_mm = &init_mm;
>
> local_ops->cache_all();
> diff --git a/arch/sparc/kernel/sun4m_smp.c b/arch/sparc/kernel/sun4m_smp.c
> index 278c40abce82..633c4cf6fdb0 100644
> --- a/arch/sparc/kernel/sun4m_smp.c
> +++ b/arch/sparc/kernel/sun4m_smp.c
> @@ -59,7 +59,7 @@ void sun4m_cpu_pre_online(void *arg)
> : "memory" /* paranoid */);
>
> /* Attach to the address space of init_task. */
> - atomic_inc(&init_mm.mm_count);
> + mmgrab(&init_mm);
> current->active_mm = &init_mm;
>
> while (!cpumask_test_cpu(cpuid, &smp_commenced_mask))
> diff --git a/arch/sparc/kernel/traps_32.c b/arch/sparc/kernel/traps_32.c
> index 4f21df7d4f13..ecddac5a4c96 100644
> --- a/arch/sparc/kernel/traps_32.c
> +++ b/arch/sparc/kernel/traps_32.c
> @@ -448,7 +448,7 @@ void trap_init(void)
> thread_info_offsets_are_bolixed_pete();
>
> /* Attach to the address space of init_task. */
> - atomic_inc(&init_mm.mm_count);
> + mmgrab(&init_mm);
> current->active_mm = &init_mm;
>
> /* NOTE: Other cpus have this done as they are started
> diff --git a/arch/sparc/kernel/traps_64.c b/arch/sparc/kernel/traps_64.c
> index 4094a51b1970..0dbbe40012ef 100644
> --- a/arch/sparc/kernel/traps_64.c
> +++ b/arch/sparc/kernel/traps_64.c
> @@ -2764,6 +2764,6 @@ void __init trap_init(void)
> /* Attach to the address space of init_task. On SMP we
> * do this in smp.c:smp_callin for other cpus.
> */
> - atomic_inc(&init_mm.mm_count);
> + mmgrab(&init_mm);
> current->active_mm = &init_mm;
> }
> diff --git a/arch/tile/kernel/smpboot.c b/arch/tile/kernel/smpboot.c
> index 6c0abaacec33..53ce940a5016 100644
> --- a/arch/tile/kernel/smpboot.c
> +++ b/arch/tile/kernel/smpboot.c
> @@ -160,7 +160,7 @@ static void start_secondary(void)
> __this_cpu_write(current_asid, min_asid);
>
> /* Set up this thread as another owner of the init_mm */
> - atomic_inc(&init_mm.mm_count);
> + mmgrab(&init_mm);
> current->active_mm = &init_mm;
> if (current->mm)
> BUG();
> diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
> index cc9e980c68ec..b580da4582e1 100644
> --- a/arch/x86/kernel/cpu/common.c
> +++ b/arch/x86/kernel/cpu/common.c
> @@ -1555,7 +1555,7 @@ void cpu_init(void)
> for (i = 0; i <= IO_BITMAP_LONGS; i++)
> t->io_bitmap[i] = ~0UL;
>
> - atomic_inc(&init_mm.mm_count);
> + mmgrab(&init_mm);
> me->active_mm = &init_mm;
> BUG_ON(me->mm);
> enter_lazy_tlb(&init_mm, me);
> @@ -1606,7 +1606,7 @@ void cpu_init(void)
> /*
> * Set up and load the per-CPU TSS and LDT
> */
> - atomic_inc(&init_mm.mm_count);
> + mmgrab(&init_mm);
> curr->active_mm = &init_mm;
> BUG_ON(curr->mm);
> enter_lazy_tlb(&init_mm, curr);
> diff --git a/arch/xtensa/kernel/smp.c b/arch/xtensa/kernel/smp.c
> index fc4ad21a5ed4..9bf5cea3bae4 100644
> --- a/arch/xtensa/kernel/smp.c
> +++ b/arch/xtensa/kernel/smp.c
> @@ -136,7 +136,7 @@ void secondary_start_kernel(void)
> /* All kernel threads share the same mm context. */
>
> atomic_inc(&mm->mm_users);
> - atomic_inc(&mm->mm_count);
> + mmgrab(mm);
> current->active_mm = mm;
> cpumask_set_cpu(cpu, mm_cpumask(mm));
> enter_lazy_tlb(mm, current);
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_process.c b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
> index ef7c8de7060e..ca5f2aa7232d 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_process.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
> @@ -262,7 +262,7 @@ static void kfd_process_notifier_release(struct mmu_notifier *mn,
> * and because the mmu_notifier_unregister function also drop
> * mm_count we need to take an extra count here.
> */
> - atomic_inc(&p->mm->mm_count);
> + mmgrab(p->mm);
> mmu_notifier_unregister_no_release(&p->mmu_notifier, p->mm);
> mmu_notifier_call_srcu(&p->rcu, &kfd_process_destroy_delayed);
> }
> diff --git a/drivers/gpu/drm/i915/i915_gem_userptr.c b/drivers/gpu/drm/i915/i915_gem_userptr.c
> index c6f780f5abc9..f21ca404af79 100644
> --- a/drivers/gpu/drm/i915/i915_gem_userptr.c
> +++ b/drivers/gpu/drm/i915/i915_gem_userptr.c
> @@ -341,7 +341,7 @@ i915_gem_userptr_init__mm_struct(struct drm_i915_gem_object *obj)
> mm->i915 = to_i915(obj->base.dev);
>
> mm->mm = current->mm;
> - atomic_inc(¤t->mm->mm_count);
> + mmgrab(current->mm);
>
> mm->mn = NULL;
>
> diff --git a/drivers/infiniband/hw/hfi1/file_ops.c b/drivers/infiniband/hw/hfi1/file_ops.c
> index bd786b7bd30b..2e1a6643a910 100644
> --- a/drivers/infiniband/hw/hfi1/file_ops.c
> +++ b/drivers/infiniband/hw/hfi1/file_ops.c
> @@ -185,7 +185,7 @@ static int hfi1_file_open(struct inode *inode, struct file *fp)
> if (fd) {
> fd->rec_cpu_num = -1; /* no cpu affinity by default */
> fd->mm = current->mm;
> - atomic_inc(&fd->mm->mm_count);
> + mmgrab(fd->mm);
> fp->private_data = fd;
> } else {
> fp->private_data = NULL;
> diff --git a/fs/proc/base.c b/fs/proc/base.c
> index ca651ac00660..0b8ccacae8b3 100644
> --- a/fs/proc/base.c
> +++ b/fs/proc/base.c
> @@ -795,7 +795,7 @@ struct mm_struct *proc_mem_open(struct inode *inode, unsigned int mode)
>
> if (!IS_ERR_OR_NULL(mm)) {
> /* ensure this mm_struct can't be freed */
> - atomic_inc(&mm->mm_count);
> + mmgrab(mm);
> /* but do not pin its memory */
> mmput(mm);
> }
> @@ -1093,7 +1093,7 @@ static int __set_oom_adj(struct file *file, int oom_adj, bool legacy)
> if (p) {
> if (atomic_read(&p->mm->mm_users) > 1) {
> mm = p->mm;
> - atomic_inc(&mm->mm_count);
> + mmgrab(mm);
> }
> task_unlock(p);
> }
> diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
> index 85959d8324df..ffa9c7cbc5fa 100644
> --- a/fs/userfaultfd.c
> +++ b/fs/userfaultfd.c
> @@ -1304,7 +1304,7 @@ static struct file *userfaultfd_file_create(int flags)
> ctx->released = false;
> ctx->mm = current->mm;
> /* prevent the mm struct to be freed */
> - atomic_inc(&ctx->mm->mm_count);
> + mmgrab(ctx->mm);
>
> file = anon_inode_getfile("[userfaultfd]", &userfaultfd_fops, ctx,
> O_RDWR | (flags & UFFD_SHARED_FCNTL_FLAGS));
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index e9c009dc3a4a..31ae1f49eebb 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -2872,6 +2872,11 @@ static inline unsigned long sigsp(unsigned long sp, struct ksignal *ksig)
> */
> extern struct mm_struct * mm_alloc(void);
>
> +static inline void mmgrab(struct mm_struct *mm)
> +{
> + atomic_inc(&mm->mm_count);
> +}
> +
> /* mmdrop drops the mm and the page tables */
> extern void __mmdrop(struct mm_struct *);
> static inline void mmdrop(struct mm_struct *mm)
> diff --git a/kernel/exit.c b/kernel/exit.c
> index 3076f3089919..b12753840050 100644
> --- a/kernel/exit.c
> +++ b/kernel/exit.c
> @@ -500,7 +500,7 @@ static void exit_mm(struct task_struct *tsk)
> __set_task_state(tsk, TASK_RUNNING);
> down_read(&mm->mmap_sem);
> }
> - atomic_inc(&mm->mm_count);
> + mmgrab(mm);
> BUG_ON(mm != tsk->active_mm);
> /* more a memory barrier than a real lock */
> task_lock(tsk);
> diff --git a/kernel/futex.c b/kernel/futex.c
> index 2c4be467fecd..cbe6056c17c1 100644
> --- a/kernel/futex.c
> +++ b/kernel/futex.c
> @@ -338,7 +338,7 @@ static inline bool should_fail_futex(bool fshared)
>
> static inline void futex_get_mm(union futex_key *key)
> {
> - atomic_inc(&key->private.mm->mm_count);
> + mmgrab(key->private.mm);
> /*
> * Ensure futex_get_mm() implies a full barrier such that
> * get_futex_key() implies a full barrier. This is relied upon
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 154fd689fe02..ee1fb0070544 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -2877,7 +2877,7 @@ context_switch(struct rq *rq, struct task_struct *prev,
>
> if (!mm) {
> next->active_mm = oldmm;
> - atomic_inc(&oldmm->mm_count);
> + mmgrab(oldmm);
> enter_lazy_tlb(oldmm, next);
> } else
> switch_mm_irqs_off(oldmm, mm, next);
> @@ -7667,7 +7667,7 @@ void __init sched_init(void)
> /*
> * The boot idle thread does lazy MMU switching as well:
> */
> - atomic_inc(&init_mm.mm_count);
> + mmgrab(&init_mm);
> enter_lazy_tlb(&init_mm, current);
>
> /*
> diff --git a/mm/khugepaged.c b/mm/khugepaged.c
> index 87e1a7ca3846..1343271a18f1 100644
> --- a/mm/khugepaged.c
> +++ b/mm/khugepaged.c
> @@ -420,7 +420,7 @@ int __khugepaged_enter(struct mm_struct *mm)
> list_add_tail(&mm_slot->mm_node, &khugepaged_scan.mm_head);
> spin_unlock(&khugepaged_mm_lock);
>
> - atomic_inc(&mm->mm_count);
> + mmgrab(mm);
> if (wakeup)
> wake_up_interruptible(&khugepaged_wait);
>
> diff --git a/mm/ksm.c b/mm/ksm.c
> index 9ae6011a41f8..5a49aad9d87b 100644
> --- a/mm/ksm.c
> +++ b/mm/ksm.c
> @@ -1813,7 +1813,7 @@ int __ksm_enter(struct mm_struct *mm)
> spin_unlock(&ksm_mmlist_lock);
>
> set_bit(MMF_VM_MERGEABLE, &mm->flags);
> - atomic_inc(&mm->mm_count);
> + mmgrab(mm);
>
> if (needs_wakeup)
> wake_up_interruptible(&ksm_thread_wait);
> diff --git a/mm/mmu_context.c b/mm/mmu_context.c
> index 6f4d27c5bb32..daf67bb02b4a 100644
> --- a/mm/mmu_context.c
> +++ b/mm/mmu_context.c
> @@ -25,7 +25,7 @@ void use_mm(struct mm_struct *mm)
> task_lock(tsk);
> active_mm = tsk->active_mm;
> if (active_mm != mm) {
> - atomic_inc(&mm->mm_count);
> + mmgrab(mm);
> tsk->active_mm = mm;
> }
> tsk->mm = mm;
> diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c
> index f4259e496f83..32bc9f2ff7eb 100644
> --- a/mm/mmu_notifier.c
> +++ b/mm/mmu_notifier.c
> @@ -275,7 +275,7 @@ static int do_mmu_notifier_register(struct mmu_notifier *mn,
> mm->mmu_notifier_mm = mmu_notifier_mm;
> mmu_notifier_mm = NULL;
> }
> - atomic_inc(&mm->mm_count);
> + mmgrab(mm);
>
> /*
> * Serialize the update against mmu_notifier_unregister. A
> diff --git a/mm/oom_kill.c b/mm/oom_kill.c
> index ec9f11d4f094..ead093c6f2a6 100644
> --- a/mm/oom_kill.c
> +++ b/mm/oom_kill.c
> @@ -660,7 +660,7 @@ static void mark_oom_victim(struct task_struct *tsk)
>
> /* oom_mm is bound to the signal struct life time. */
> if (!cmpxchg(&tsk->signal->oom_mm, NULL, mm))
> - atomic_inc(&tsk->signal->oom_mm->mm_count);
> + mmgrab(tsk->signal->oom_mm);
>
> /*
> * Make sure that the task is woken up from uninterruptible sleep
> @@ -877,7 +877,7 @@ static void oom_kill_process(struct oom_control *oc, const char *message)
>
> /* Get a reference to safely compare mm after task_unlock(victim) */
> mm = victim->mm;
> - atomic_inc(&mm->mm_count);
> + mmgrab(mm);
> /*
> * We should send SIGKILL before setting TIF_MEMDIE in order to prevent
> * the OOM victim from depleting the memory reserves from the user
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 7f9ee2929cfe..43914b981691 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -613,7 +613,7 @@ static struct kvm *kvm_create_vm(unsigned long type)
> return ERR_PTR(-ENOMEM);
>
> spin_lock_init(&kvm->mmu_lock);
> - atomic_inc(¤t->mm->mm_count);
> + mmgrab(current->mm);
> kvm->mm = current->mm;
> kvm_eventfd_init(kvm);
> mutex_init(&kvm->lock);
> --
> 2.11.0.1.gaa10c3f
>
--
Michal Hocko
SUSE Labs
^ permalink raw reply [flat|nested] 15+ messages in thread
* [PATCH 1/4] mm: add new mmgrab() helper
@ 2016-12-16 8:21 Vegard Nossum
2016-12-16 9:14 ` Michal Hocko
2016-12-16 9:56 ` Peter Zijlstra
0 siblings, 2 replies; 15+ messages in thread
From: Vegard Nossum @ 2016-12-16 8:21 UTC (permalink / raw)
To: linux-mm, linux-kernel
Cc: Rik van Riel, Matthew Wilcox, Peter Zijlstra, Andrew Morton,
Michal Hocko, Al Viro, Ingo Molnar, Linus Torvalds,
Vegard Nossum
Apart from adding the helper function itself, the rest of the kernel is
converted mechanically using:
git grep -l 'atomic_inc.*mm_count' | xargs sed -i 's/atomic_inc(&\(.*\)->mm_count);/mmgrab\(\1\);/'
git grep -l 'atomic_inc.*mm_count' | xargs sed -i 's/atomic_inc(&\(.*\)\.mm_count);/mmgrab\(\&\1\);/'
This is needed for a later patch that hooks into the helper, but might be
a worthwhile cleanup on its own.
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
---
arch/alpha/kernel/smp.c | 2 +-
arch/arc/kernel/smp.c | 2 +-
arch/arm/kernel/smp.c | 2 +-
arch/arm64/kernel/smp.c | 2 +-
arch/blackfin/mach-common/smp.c | 2 +-
arch/hexagon/kernel/smp.c | 2 +-
arch/ia64/kernel/setup.c | 2 +-
arch/m32r/kernel/setup.c | 2 +-
arch/metag/kernel/smp.c | 2 +-
arch/mips/kernel/traps.c | 2 +-
arch/mn10300/kernel/smp.c | 2 +-
arch/parisc/kernel/smp.c | 2 +-
arch/powerpc/kernel/smp.c | 2 +-
arch/s390/kernel/processor.c | 2 +-
arch/score/kernel/traps.c | 2 +-
arch/sh/kernel/smp.c | 2 +-
arch/sparc/kernel/leon_smp.c | 2 +-
arch/sparc/kernel/smp_64.c | 2 +-
arch/sparc/kernel/sun4d_smp.c | 2 +-
arch/sparc/kernel/sun4m_smp.c | 2 +-
arch/sparc/kernel/traps_32.c | 2 +-
arch/sparc/kernel/traps_64.c | 2 +-
arch/tile/kernel/smpboot.c | 2 +-
arch/x86/kernel/cpu/common.c | 4 ++--
arch/xtensa/kernel/smp.c | 2 +-
drivers/gpu/drm/amd/amdkfd/kfd_process.c | 2 +-
drivers/gpu/drm/i915/i915_gem_userptr.c | 2 +-
drivers/infiniband/hw/hfi1/file_ops.c | 2 +-
fs/proc/base.c | 4 ++--
fs/userfaultfd.c | 2 +-
include/linux/sched.h | 5 +++++
kernel/exit.c | 2 +-
kernel/futex.c | 2 +-
kernel/sched/core.c | 4 ++--
mm/khugepaged.c | 2 +-
mm/ksm.c | 2 +-
mm/mmu_context.c | 2 +-
mm/mmu_notifier.c | 2 +-
mm/oom_kill.c | 4 ++--
virt/kvm/kvm_main.c | 2 +-
40 files changed, 48 insertions(+), 43 deletions(-)
diff --git a/arch/alpha/kernel/smp.c b/arch/alpha/kernel/smp.c
index 46bf263c3153..acb4b146a607 100644
--- a/arch/alpha/kernel/smp.c
+++ b/arch/alpha/kernel/smp.c
@@ -144,7 +144,7 @@ smp_callin(void)
alpha_mv.smp_callin();
/* All kernel threads share the same mm context. */
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
current->active_mm = &init_mm;
/* inform the notifiers about the new cpu */
diff --git a/arch/arc/kernel/smp.c b/arch/arc/kernel/smp.c
index 88674d972c9d..9cbc7aba3ede 100644
--- a/arch/arc/kernel/smp.c
+++ b/arch/arc/kernel/smp.c
@@ -125,7 +125,7 @@ void start_kernel_secondary(void)
setup_processor();
atomic_inc(&mm->mm_users);
- atomic_inc(&mm->mm_count);
+ mmgrab(mm);
current->active_mm = mm;
cpumask_set_cpu(cpu, mm_cpumask(mm));
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 7dd14e8395e6..c6514ce0fcbc 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -371,7 +371,7 @@ asmlinkage void secondary_start_kernel(void)
* reference and switch to it.
*/
cpu = smp_processor_id();
- atomic_inc(&mm->mm_count);
+ mmgrab(mm);
current->active_mm = mm;
cpumask_set_cpu(cpu, mm_cpumask(mm));
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 8507703dabe4..61969ea29654 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -214,7 +214,7 @@ asmlinkage void secondary_start_kernel(void)
* All kernel threads share the same mm context; grab a
* reference and switch to it.
*/
- atomic_inc(&mm->mm_count);
+ mmgrab(mm);
current->active_mm = mm;
set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
diff --git a/arch/blackfin/mach-common/smp.c b/arch/blackfin/mach-common/smp.c
index 23c4ef5f8bdc..bc5617ef7128 100644
--- a/arch/blackfin/mach-common/smp.c
+++ b/arch/blackfin/mach-common/smp.c
@@ -308,7 +308,7 @@ void secondary_start_kernel(void)
/* Attach the new idle task to the global mm. */
atomic_inc(&mm->mm_users);
- atomic_inc(&mm->mm_count);
+ mmgrab(mm);
current->active_mm = mm;
preempt_disable();
diff --git a/arch/hexagon/kernel/smp.c b/arch/hexagon/kernel/smp.c
index 983bae7d2665..c02a6455839e 100644
--- a/arch/hexagon/kernel/smp.c
+++ b/arch/hexagon/kernel/smp.c
@@ -162,7 +162,7 @@ void start_secondary(void)
);
/* Set the memory struct */
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
current->active_mm = &init_mm;
cpu = smp_processor_id();
diff --git a/arch/ia64/kernel/setup.c b/arch/ia64/kernel/setup.c
index 7ec7acc844c2..ecbff47b01f1 100644
--- a/arch/ia64/kernel/setup.c
+++ b/arch/ia64/kernel/setup.c
@@ -992,7 +992,7 @@ cpu_init (void)
*/
ia64_setreg(_IA64_REG_CR_DCR, ( IA64_DCR_DP | IA64_DCR_DK | IA64_DCR_DX | IA64_DCR_DR
| IA64_DCR_DA | IA64_DCR_DD | IA64_DCR_LC));
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
current->active_mm = &init_mm;
BUG_ON(current->mm);
diff --git a/arch/m32r/kernel/setup.c b/arch/m32r/kernel/setup.c
index 136c69f1fb8a..b18bc0bd6544 100644
--- a/arch/m32r/kernel/setup.c
+++ b/arch/m32r/kernel/setup.c
@@ -403,7 +403,7 @@ void __init cpu_init (void)
printk(KERN_INFO "Initializing CPU#%d\n", cpu_id);
/* Set up and load the per-CPU TSS and LDT */
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
current->active_mm = &init_mm;
if (current->mm)
BUG();
diff --git a/arch/metag/kernel/smp.c b/arch/metag/kernel/smp.c
index bad13232de51..af9cff547a19 100644
--- a/arch/metag/kernel/smp.c
+++ b/arch/metag/kernel/smp.c
@@ -345,7 +345,7 @@ asmlinkage void secondary_start_kernel(void)
* reference and switch to it.
*/
atomic_inc(&mm->mm_users);
- atomic_inc(&mm->mm_count);
+ mmgrab(mm);
current->active_mm = mm;
cpumask_set_cpu(cpu, mm_cpumask(mm));
enter_lazy_tlb(mm, current);
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 3905003dfe2b..e50b0e0ca44c 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -2177,7 +2177,7 @@ void per_cpu_trap_init(bool is_boot_cpu)
if (!cpu_data[cpu].asid_cache)
cpu_data[cpu].asid_cache = asid_first_version(cpu);
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
current->active_mm = &init_mm;
BUG_ON(current->mm);
enter_lazy_tlb(&init_mm, current);
diff --git a/arch/mn10300/kernel/smp.c b/arch/mn10300/kernel/smp.c
index 426173c4b0b9..e65b5cc2fa67 100644
--- a/arch/mn10300/kernel/smp.c
+++ b/arch/mn10300/kernel/smp.c
@@ -589,7 +589,7 @@ static void __init smp_cpu_init(void)
}
printk(KERN_INFO "Initializing CPU#%d\n", cpu_id);
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
current->active_mm = &init_mm;
BUG_ON(current->mm);
diff --git a/arch/parisc/kernel/smp.c b/arch/parisc/kernel/smp.c
index 75dab2871346..67b452b41ff6 100644
--- a/arch/parisc/kernel/smp.c
+++ b/arch/parisc/kernel/smp.c
@@ -279,7 +279,7 @@ smp_cpu_init(int cpunum)
set_cpu_online(cpunum, true);
/* Initialise the idle task for this CPU */
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
current->active_mm = &init_mm;
BUG_ON(current->mm);
enter_lazy_tlb(&init_mm, current);
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 9c6f3fd58059..42b82364c782 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -707,7 +707,7 @@ void start_secondary(void *unused)
unsigned int cpu = smp_processor_id();
int i, base;
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
current->active_mm = &init_mm;
smp_store_cpu_info(cpu);
diff --git a/arch/s390/kernel/processor.c b/arch/s390/kernel/processor.c
index 81d0808085e6..ec9bc100895c 100644
--- a/arch/s390/kernel/processor.c
+++ b/arch/s390/kernel/processor.c
@@ -73,7 +73,7 @@ void cpu_init(void)
get_cpu_id(id);
if (machine_has_cpu_mhz)
update_cpu_mhz(NULL);
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
current->active_mm = &init_mm;
BUG_ON(current->mm);
enter_lazy_tlb(&init_mm, current);
diff --git a/arch/score/kernel/traps.c b/arch/score/kernel/traps.c
index 5cea1e750cec..6f6e5a39d147 100644
--- a/arch/score/kernel/traps.c
+++ b/arch/score/kernel/traps.c
@@ -336,7 +336,7 @@ void __init trap_init(void)
set_except_vector(18, handle_dbe);
flush_icache_range(DEBUG_VECTOR_BASE_ADDR, IRQ_VECTOR_BASE_ADDR);
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
current->active_mm = &init_mm;
cpu_cache_init();
}
diff --git a/arch/sh/kernel/smp.c b/arch/sh/kernel/smp.c
index 38e7860845db..ee379c699c08 100644
--- a/arch/sh/kernel/smp.c
+++ b/arch/sh/kernel/smp.c
@@ -178,7 +178,7 @@ asmlinkage void start_secondary(void)
struct mm_struct *mm = &init_mm;
enable_mmu();
- atomic_inc(&mm->mm_count);
+ mmgrab(mm);
atomic_inc(&mm->mm_users);
current->active_mm = mm;
#ifdef CONFIG_MMU
diff --git a/arch/sparc/kernel/leon_smp.c b/arch/sparc/kernel/leon_smp.c
index 71e16f2241c2..b99d33797e1d 100644
--- a/arch/sparc/kernel/leon_smp.c
+++ b/arch/sparc/kernel/leon_smp.c
@@ -93,7 +93,7 @@ void leon_cpu_pre_online(void *arg)
: "memory" /* paranoid */);
/* Attach to the address space of init_task. */
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
current->active_mm = &init_mm;
while (!cpumask_test_cpu(cpuid, &smp_commenced_mask))
diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c
index 8182f7caf5b1..c1d2bed22961 100644
--- a/arch/sparc/kernel/smp_64.c
+++ b/arch/sparc/kernel/smp_64.c
@@ -122,7 +122,7 @@ void smp_callin(void)
current_thread_info()->new_child = 0;
/* Attach to the address space of init_task. */
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
current->active_mm = &init_mm;
/* inform the notifiers about the new cpu */
diff --git a/arch/sparc/kernel/sun4d_smp.c b/arch/sparc/kernel/sun4d_smp.c
index 9d98e5002a09..7b55c50eabe5 100644
--- a/arch/sparc/kernel/sun4d_smp.c
+++ b/arch/sparc/kernel/sun4d_smp.c
@@ -93,7 +93,7 @@ void sun4d_cpu_pre_online(void *arg)
show_leds(cpuid);
/* Attach to the address space of init_task. */
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
current->active_mm = &init_mm;
local_ops->cache_all();
diff --git a/arch/sparc/kernel/sun4m_smp.c b/arch/sparc/kernel/sun4m_smp.c
index 278c40abce82..633c4cf6fdb0 100644
--- a/arch/sparc/kernel/sun4m_smp.c
+++ b/arch/sparc/kernel/sun4m_smp.c
@@ -59,7 +59,7 @@ void sun4m_cpu_pre_online(void *arg)
: "memory" /* paranoid */);
/* Attach to the address space of init_task. */
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
current->active_mm = &init_mm;
while (!cpumask_test_cpu(cpuid, &smp_commenced_mask))
diff --git a/arch/sparc/kernel/traps_32.c b/arch/sparc/kernel/traps_32.c
index 4f21df7d4f13..ecddac5a4c96 100644
--- a/arch/sparc/kernel/traps_32.c
+++ b/arch/sparc/kernel/traps_32.c
@@ -448,7 +448,7 @@ void trap_init(void)
thread_info_offsets_are_bolixed_pete();
/* Attach to the address space of init_task. */
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
current->active_mm = &init_mm;
/* NOTE: Other cpus have this done as they are started
diff --git a/arch/sparc/kernel/traps_64.c b/arch/sparc/kernel/traps_64.c
index 4094a51b1970..0dbbe40012ef 100644
--- a/arch/sparc/kernel/traps_64.c
+++ b/arch/sparc/kernel/traps_64.c
@@ -2764,6 +2764,6 @@ void __init trap_init(void)
/* Attach to the address space of init_task. On SMP we
* do this in smp.c:smp_callin for other cpus.
*/
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
current->active_mm = &init_mm;
}
diff --git a/arch/tile/kernel/smpboot.c b/arch/tile/kernel/smpboot.c
index 6c0abaacec33..53ce940a5016 100644
--- a/arch/tile/kernel/smpboot.c
+++ b/arch/tile/kernel/smpboot.c
@@ -160,7 +160,7 @@ static void start_secondary(void)
__this_cpu_write(current_asid, min_asid);
/* Set up this thread as another owner of the init_mm */
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
current->active_mm = &init_mm;
if (current->mm)
BUG();
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index cc9e980c68ec..b580da4582e1 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1555,7 +1555,7 @@ void cpu_init(void)
for (i = 0; i <= IO_BITMAP_LONGS; i++)
t->io_bitmap[i] = ~0UL;
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
me->active_mm = &init_mm;
BUG_ON(me->mm);
enter_lazy_tlb(&init_mm, me);
@@ -1606,7 +1606,7 @@ void cpu_init(void)
/*
* Set up and load the per-CPU TSS and LDT
*/
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
curr->active_mm = &init_mm;
BUG_ON(curr->mm);
enter_lazy_tlb(&init_mm, curr);
diff --git a/arch/xtensa/kernel/smp.c b/arch/xtensa/kernel/smp.c
index fc4ad21a5ed4..9bf5cea3bae4 100644
--- a/arch/xtensa/kernel/smp.c
+++ b/arch/xtensa/kernel/smp.c
@@ -136,7 +136,7 @@ void secondary_start_kernel(void)
/* All kernel threads share the same mm context. */
atomic_inc(&mm->mm_users);
- atomic_inc(&mm->mm_count);
+ mmgrab(mm);
current->active_mm = mm;
cpumask_set_cpu(cpu, mm_cpumask(mm));
enter_lazy_tlb(mm, current);
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_process.c b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
index ef7c8de7060e..ca5f2aa7232d 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_process.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
@@ -262,7 +262,7 @@ static void kfd_process_notifier_release(struct mmu_notifier *mn,
* and because the mmu_notifier_unregister function also drop
* mm_count we need to take an extra count here.
*/
- atomic_inc(&p->mm->mm_count);
+ mmgrab(p->mm);
mmu_notifier_unregister_no_release(&p->mmu_notifier, p->mm);
mmu_notifier_call_srcu(&p->rcu, &kfd_process_destroy_delayed);
}
diff --git a/drivers/gpu/drm/i915/i915_gem_userptr.c b/drivers/gpu/drm/i915/i915_gem_userptr.c
index c6f780f5abc9..f21ca404af79 100644
--- a/drivers/gpu/drm/i915/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/i915_gem_userptr.c
@@ -341,7 +341,7 @@ i915_gem_userptr_init__mm_struct(struct drm_i915_gem_object *obj)
mm->i915 = to_i915(obj->base.dev);
mm->mm = current->mm;
- atomic_inc(¤t->mm->mm_count);
+ mmgrab(current->mm);
mm->mn = NULL;
diff --git a/drivers/infiniband/hw/hfi1/file_ops.c b/drivers/infiniband/hw/hfi1/file_ops.c
index bd786b7bd30b..2e1a6643a910 100644
--- a/drivers/infiniband/hw/hfi1/file_ops.c
+++ b/drivers/infiniband/hw/hfi1/file_ops.c
@@ -185,7 +185,7 @@ static int hfi1_file_open(struct inode *inode, struct file *fp)
if (fd) {
fd->rec_cpu_num = -1; /* no cpu affinity by default */
fd->mm = current->mm;
- atomic_inc(&fd->mm->mm_count);
+ mmgrab(fd->mm);
fp->private_data = fd;
} else {
fp->private_data = NULL;
diff --git a/fs/proc/base.c b/fs/proc/base.c
index ca651ac00660..0b8ccacae8b3 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -795,7 +795,7 @@ struct mm_struct *proc_mem_open(struct inode *inode, unsigned int mode)
if (!IS_ERR_OR_NULL(mm)) {
/* ensure this mm_struct can't be freed */
- atomic_inc(&mm->mm_count);
+ mmgrab(mm);
/* but do not pin its memory */
mmput(mm);
}
@@ -1093,7 +1093,7 @@ static int __set_oom_adj(struct file *file, int oom_adj, bool legacy)
if (p) {
if (atomic_read(&p->mm->mm_users) > 1) {
mm = p->mm;
- atomic_inc(&mm->mm_count);
+ mmgrab(mm);
}
task_unlock(p);
}
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 85959d8324df..ffa9c7cbc5fa 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -1304,7 +1304,7 @@ static struct file *userfaultfd_file_create(int flags)
ctx->released = false;
ctx->mm = current->mm;
/* prevent the mm struct to be freed */
- atomic_inc(&ctx->mm->mm_count);
+ mmgrab(ctx->mm);
file = anon_inode_getfile("[userfaultfd]", &userfaultfd_fops, ctx,
O_RDWR | (flags & UFFD_SHARED_FCNTL_FLAGS));
diff --git a/include/linux/sched.h b/include/linux/sched.h
index e9c009dc3a4a..31ae1f49eebb 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2872,6 +2872,11 @@ static inline unsigned long sigsp(unsigned long sp, struct ksignal *ksig)
*/
extern struct mm_struct * mm_alloc(void);
+static inline void mmgrab(struct mm_struct *mm)
+{
+ atomic_inc(&mm->mm_count);
+}
+
/* mmdrop drops the mm and the page tables */
extern void __mmdrop(struct mm_struct *);
static inline void mmdrop(struct mm_struct *mm)
diff --git a/kernel/exit.c b/kernel/exit.c
index 3076f3089919..b12753840050 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -500,7 +500,7 @@ static void exit_mm(struct task_struct *tsk)
__set_task_state(tsk, TASK_RUNNING);
down_read(&mm->mmap_sem);
}
- atomic_inc(&mm->mm_count);
+ mmgrab(mm);
BUG_ON(mm != tsk->active_mm);
/* more a memory barrier than a real lock */
task_lock(tsk);
diff --git a/kernel/futex.c b/kernel/futex.c
index 2c4be467fecd..cbe6056c17c1 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -338,7 +338,7 @@ static inline bool should_fail_futex(bool fshared)
static inline void futex_get_mm(union futex_key *key)
{
- atomic_inc(&key->private.mm->mm_count);
+ mmgrab(key->private.mm);
/*
* Ensure futex_get_mm() implies a full barrier such that
* get_futex_key() implies a full barrier. This is relied upon
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 154fd689fe02..ee1fb0070544 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2877,7 +2877,7 @@ context_switch(struct rq *rq, struct task_struct *prev,
if (!mm) {
next->active_mm = oldmm;
- atomic_inc(&oldmm->mm_count);
+ mmgrab(oldmm);
enter_lazy_tlb(oldmm, next);
} else
switch_mm_irqs_off(oldmm, mm, next);
@@ -7667,7 +7667,7 @@ void __init sched_init(void)
/*
* The boot idle thread does lazy MMU switching as well:
*/
- atomic_inc(&init_mm.mm_count);
+ mmgrab(&init_mm);
enter_lazy_tlb(&init_mm, current);
/*
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 87e1a7ca3846..1343271a18f1 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -420,7 +420,7 @@ int __khugepaged_enter(struct mm_struct *mm)
list_add_tail(&mm_slot->mm_node, &khugepaged_scan.mm_head);
spin_unlock(&khugepaged_mm_lock);
- atomic_inc(&mm->mm_count);
+ mmgrab(mm);
if (wakeup)
wake_up_interruptible(&khugepaged_wait);
diff --git a/mm/ksm.c b/mm/ksm.c
index 9ae6011a41f8..5a49aad9d87b 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -1813,7 +1813,7 @@ int __ksm_enter(struct mm_struct *mm)
spin_unlock(&ksm_mmlist_lock);
set_bit(MMF_VM_MERGEABLE, &mm->flags);
- atomic_inc(&mm->mm_count);
+ mmgrab(mm);
if (needs_wakeup)
wake_up_interruptible(&ksm_thread_wait);
diff --git a/mm/mmu_context.c b/mm/mmu_context.c
index 6f4d27c5bb32..daf67bb02b4a 100644
--- a/mm/mmu_context.c
+++ b/mm/mmu_context.c
@@ -25,7 +25,7 @@ void use_mm(struct mm_struct *mm)
task_lock(tsk);
active_mm = tsk->active_mm;
if (active_mm != mm) {
- atomic_inc(&mm->mm_count);
+ mmgrab(mm);
tsk->active_mm = mm;
}
tsk->mm = mm;
diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c
index f4259e496f83..32bc9f2ff7eb 100644
--- a/mm/mmu_notifier.c
+++ b/mm/mmu_notifier.c
@@ -275,7 +275,7 @@ static int do_mmu_notifier_register(struct mmu_notifier *mn,
mm->mmu_notifier_mm = mmu_notifier_mm;
mmu_notifier_mm = NULL;
}
- atomic_inc(&mm->mm_count);
+ mmgrab(mm);
/*
* Serialize the update against mmu_notifier_unregister. A
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index ec9f11d4f094..ead093c6f2a6 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -660,7 +660,7 @@ static void mark_oom_victim(struct task_struct *tsk)
/* oom_mm is bound to the signal struct life time. */
if (!cmpxchg(&tsk->signal->oom_mm, NULL, mm))
- atomic_inc(&tsk->signal->oom_mm->mm_count);
+ mmgrab(tsk->signal->oom_mm);
/*
* Make sure that the task is woken up from uninterruptible sleep
@@ -877,7 +877,7 @@ static void oom_kill_process(struct oom_control *oc, const char *message)
/* Get a reference to safely compare mm after task_unlock(victim) */
mm = victim->mm;
- atomic_inc(&mm->mm_count);
+ mmgrab(mm);
/*
* We should send SIGKILL before setting TIF_MEMDIE in order to prevent
* the OOM victim from depleting the memory reserves from the user
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 7f9ee2929cfe..43914b981691 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -613,7 +613,7 @@ static struct kvm *kvm_create_vm(unsigned long type)
return ERR_PTR(-ENOMEM);
spin_lock_init(&kvm->mmu_lock);
- atomic_inc(¤t->mm->mm_count);
+ mmgrab(current->mm);
kvm->mm = current->mm;
kvm_eventfd_init(kvm);
mutex_init(&kvm->lock);
--
2.11.0.1.gaa10c3f
^ permalink raw reply related [flat|nested] 15+ messages in thread
end of thread, other threads:[~2017-01-09 23:16 UTC | newest]
Thread overview: 15+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-12-18 12:32 [PATCH 1/4] mm: add new mmgrab() helper Vegard Nossum
2016-12-18 12:32 ` [PATCH 2/4] mm: add new mmget() helper Vegard Nossum
2017-01-09 23:18 ` Andrew Morton
2016-12-18 12:32 ` [PATCH 3/4] mm: use mmget_not_zero() helper Vegard Nossum
2016-12-18 12:32 ` [PATCH 4/4] mm: clarify mm_struct.mm_{users,count} documentation Vegard Nossum
2016-12-19 13:15 ` Michal Hocko
2016-12-19 10:29 ` [PATCH 1/4] mm: add new mmgrab() helper Peter Zijlstra
2016-12-22 22:03 ` David Rientjes
-- strict thread matches above, loose matches on Subject: below --
2016-12-16 8:21 Vegard Nossum
2016-12-16 9:14 ` Michal Hocko
2016-12-16 9:56 ` Peter Zijlstra
2016-12-16 10:19 ` Kirill A. Shutemov
2016-12-16 10:20 ` Vegard Nossum
2016-12-16 10:36 ` Michal Hocko
2016-12-16 11:14 ` Vegard Nossum
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