* [PATCH 1/2] asm-generic/tlb: introduce HAVE_MMU_GATHER_NO_GATHER
2018-09-18 12:51 [RFC][PATCH 0/2] convert s390 to generic mmu_gather Martin Schwidefsky
@ 2018-09-18 12:51 ` Martin Schwidefsky
2018-09-18 12:51 ` [PATCH 2/2] s390/tlb: convert to generic mmu_gather Martin Schwidefsky
1 sibling, 0 replies; 6+ messages in thread
From: Martin Schwidefsky @ 2018-09-18 12:51 UTC (permalink / raw)
To: Peter Zijlstra
Cc: will.deacon, aneesh.kumar, akpm, npiggin, linux-arch, linux-mm,
linux-kernel, linux, heiko.carstens, Linus Torvalds,
Martin Schwidefsky
Add the Kconfig option HAVE_MMU_GATHER_NO_GATHER to the generic
mmu_gather code. If the option is set the mmu_gather will not
track individual pages for delayed page free anymore. A platform
that enables the option needs to provide its own implementation
of the __tlb_remove_page_size function to free pages.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---
arch/Kconfig | 3 ++
include/asm-generic/tlb.h | 9 +++-
mm/mmu_gather.c | 114 +++++++++++++++++++++++++++-------------------
3 files changed, 77 insertions(+), 49 deletions(-)
diff --git a/arch/Kconfig b/arch/Kconfig
index 053c44703539..edb338b66f16 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -368,6 +368,9 @@ config HAVE_RCU_TABLE_INVALIDATE
config HAVE_MMU_GATHER_PAGE_SIZE
bool
+config HAVE_MMU_GATHER_NO_GATHER
+ bool
+
config ARCH_HAVE_NMI_SAFE_CMPXCHG
bool
diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h
index 21c751cd751e..9e714e1b6695 100644
--- a/include/asm-generic/tlb.h
+++ b/include/asm-generic/tlb.h
@@ -179,6 +179,7 @@ extern void tlb_remove_table(struct mmu_gather *tlb, void *table);
#endif
+#ifndef CONFIG_HAVE_MMU_GATHER_NO_GATHER
/*
* If we can't allocate a page to make a big batch of page pointers
* to work on, then just handle a few from the on-stack structure.
@@ -203,6 +204,10 @@ struct mmu_gather_batch {
*/
#define MAX_GATHER_BATCH_COUNT (10000UL/MAX_GATHER_BATCH)
+extern bool __tlb_remove_page_size(struct mmu_gather *tlb, struct page *page,
+ int page_size);
+#endif
+
/*
* struct mmu_gather is an opaque type used by the mm code for passing around
* any data needed by arch specific code for tlb_remove_page.
@@ -249,6 +254,7 @@ struct mmu_gather {
unsigned int batch_count;
+#ifndef CONFIG_HAVE_MMU_GATHER_NO_GATHER
struct mmu_gather_batch *active;
struct mmu_gather_batch local;
struct page *__pages[MMU_GATHER_BUNDLE];
@@ -256,6 +262,7 @@ struct mmu_gather {
#ifdef CONFIG_HAVE_MMU_GATHER_PAGE_SIZE
unsigned int page_size;
#endif
+#endif
};
void arch_tlb_gather_mmu(struct mmu_gather *tlb,
@@ -264,8 +271,6 @@ void tlb_flush_mmu(struct mmu_gather *tlb);
void arch_tlb_finish_mmu(struct mmu_gather *tlb,
unsigned long start, unsigned long end, bool force);
void tlb_flush_mmu_free(struct mmu_gather *tlb);
-extern bool __tlb_remove_page_size(struct mmu_gather *tlb, struct page *page,
- int page_size);
static inline void __tlb_adjust_range(struct mmu_gather *tlb,
unsigned long address,
diff --git a/mm/mmu_gather.c b/mm/mmu_gather.c
index 2d5e617131f6..6d5d812a040b 100644
--- a/mm/mmu_gather.c
+++ b/mm/mmu_gather.c
@@ -13,6 +13,8 @@
#ifdef HAVE_GENERIC_MMU_GATHER
+#ifndef CONFIG_HAVE_MMU_GATHER_NO_GATHER
+
static bool tlb_next_batch(struct mmu_gather *tlb)
{
struct mmu_gather_batch *batch;
@@ -41,6 +43,63 @@ static bool tlb_next_batch(struct mmu_gather *tlb)
return true;
}
+static void tlb_batch_pages_flush(struct mmu_gather *tlb)
+{
+ struct mmu_gather_batch *batch;
+
+ for (batch = &tlb->local; batch && batch->nr; batch = batch->next) {
+ free_pages_and_swap_cache(batch->pages, batch->nr);
+ batch->nr = 0;
+ }
+ tlb->active = &tlb->local;
+}
+
+static void tlb_batch_list_free(struct mmu_gather *tlb)
+{
+ struct mmu_gather_batch *batch, *next;
+
+ for (batch = tlb->local.next; batch; batch = next) {
+ next = batch->next;
+ free_pages((unsigned long)batch, 0);
+ }
+ tlb->local.next = NULL;
+}
+
+/* __tlb_remove_page
+ * Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)), while
+ * handling the additional races in SMP caused by other CPUs caching valid
+ * mappings in their TLBs. Returns the number of free page slots left.
+ * When out of page slots we must call tlb_flush_mmu().
+ *returns true if the caller should flush.
+ */
+bool __tlb_remove_page_size(struct mmu_gather *tlb, struct page *page, int page_size)
+{
+ struct mmu_gather_batch *batch;
+
+ VM_BUG_ON(!tlb->end);
+
+#ifdef CONFIG_HAVE_MMU_GATHER_PAGE_SIZE
+ VM_WARN_ON(tlb->page_size != page_size);
+#endif
+
+ batch = tlb->active;
+ /*
+ * Add the page and check if we are full. If so
+ * force a flush.
+ */
+ batch->pages[batch->nr++] = page;
+ if (batch->nr == batch->max) {
+ if (!tlb_next_batch(tlb))
+ return true;
+ batch = tlb->active;
+ }
+ VM_BUG_ON_PAGE(batch->nr > batch->max, page);
+
+ return false;
+}
+
+#endif
+
void arch_tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm,
unsigned long start, unsigned long end)
{
@@ -48,12 +107,15 @@ void arch_tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm,
/* Is it from 0 to ~0? */
tlb->fullmm = !(start | (end+1));
+
+#ifndef CONFIG_HAVE_MMU_GATHER_NO_GATHER
tlb->need_flush_all = 0;
tlb->local.next = NULL;
tlb->local.nr = 0;
tlb->local.max = ARRAY_SIZE(tlb->__pages);
tlb->active = &tlb->local;
tlb->batch_count = 0;
+#endif
#ifdef CONFIG_HAVE_RCU_TABLE_FREE
tlb->batch = NULL;
@@ -67,16 +129,12 @@ void arch_tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm,
void tlb_flush_mmu_free(struct mmu_gather *tlb)
{
- struct mmu_gather_batch *batch;
-
#ifdef CONFIG_HAVE_RCU_TABLE_FREE
tlb_table_flush(tlb);
#endif
- for (batch = &tlb->local; batch && batch->nr; batch = batch->next) {
- free_pages_and_swap_cache(batch->pages, batch->nr);
- batch->nr = 0;
- }
- tlb->active = &tlb->local;
+#ifndef CONFIG_HAVE_MMU_GATHER_NO_GATHER
+ tlb_batch_pages_flush(tlb);
+#endif
}
void tlb_flush_mmu(struct mmu_gather *tlb)
@@ -92,8 +150,6 @@ void tlb_flush_mmu(struct mmu_gather *tlb)
void arch_tlb_finish_mmu(struct mmu_gather *tlb,
unsigned long start, unsigned long end, bool force)
{
- struct mmu_gather_batch *batch, *next;
-
if (force) {
__tlb_reset_range(tlb);
__tlb_adjust_range(tlb, start, end - start);
@@ -103,45 +159,9 @@ void arch_tlb_finish_mmu(struct mmu_gather *tlb,
/* keep the page table cache within bounds */
check_pgt_cache();
-
- for (batch = tlb->local.next; batch; batch = next) {
- next = batch->next;
- free_pages((unsigned long)batch, 0);
- }
- tlb->local.next = NULL;
-}
-
-/* __tlb_remove_page
- * Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)), while
- * handling the additional races in SMP caused by other CPUs caching valid
- * mappings in their TLBs. Returns the number of free page slots left.
- * When out of page slots we must call tlb_flush_mmu().
- *returns true if the caller should flush.
- */
-bool __tlb_remove_page_size(struct mmu_gather *tlb, struct page *page, int page_size)
-{
- struct mmu_gather_batch *batch;
-
- VM_BUG_ON(!tlb->end);
-
-#ifdef CONFIG_HAVE_MMU_GATHER_PAGE_SIZE
- VM_WARN_ON(tlb->page_size != page_size);
+#ifndef CONFIG_HAVE_MMU_GATHER_NO_GATHER
+ tlb_batch_list_free(tlb);
#endif
-
- batch = tlb->active;
- /*
- * Add the page and check if we are full. If so
- * force a flush.
- */
- batch->pages[batch->nr++] = page;
- if (batch->nr == batch->max) {
- if (!tlb_next_batch(tlb))
- return true;
- batch = tlb->active;
- }
- VM_BUG_ON_PAGE(batch->nr > batch->max, page);
-
- return false;
}
#endif /* HAVE_GENERIC_MMU_GATHER */
--
2.16.4
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 2/2] s390/tlb: convert to generic mmu_gather
2018-09-18 12:51 [RFC][PATCH 0/2] convert s390 to generic mmu_gather Martin Schwidefsky
2018-09-18 12:51 ` [PATCH 1/2] asm-generic/tlb: introduce HAVE_MMU_GATHER_NO_GATHER Martin Schwidefsky
@ 2018-09-18 12:51 ` Martin Schwidefsky
2018-09-19 12:38 ` Peter Zijlstra
1 sibling, 1 reply; 6+ messages in thread
From: Martin Schwidefsky @ 2018-09-18 12:51 UTC (permalink / raw)
To: Peter Zijlstra
Cc: will.deacon, aneesh.kumar, akpm, npiggin, linux-arch, linux-mm,
linux-kernel, linux, heiko.carstens, Linus Torvalds,
Martin Schwidefsky
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---
arch/s390/Kconfig | 3 +
arch/s390/include/asm/tlb.h | 130 ++++++++++++++------------------------------
arch/s390/mm/pgalloc.c | 63 +--------------------
3 files changed, 44 insertions(+), 152 deletions(-)
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 9a9c7a6fe925..b864462ac4a6 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -157,10 +157,13 @@ config S390
select HAVE_MEMBLOCK
select HAVE_MEMBLOCK_NODE_MAP
select HAVE_MEMBLOCK_PHYS_MAP
+ select HAVE_MMU_GATHER_NO_GATHER
select HAVE_MOD_ARCH_SPECIFIC
select HAVE_NOP_MCOUNT
select HAVE_OPROFILE
select HAVE_PERF_EVENTS
+ select HAVE_RCU_TABLE_FREE
+ select HAVE_RCU_TABLE_INVALIDATE
select HAVE_REGS_AND_STACK_ACCESS_API
select HAVE_RSEQ
select HAVE_SYSCALL_TRACEPOINTS
diff --git a/arch/s390/include/asm/tlb.h b/arch/s390/include/asm/tlb.h
index cf3d64313740..cb99f8310c3a 100644
--- a/arch/s390/include/asm/tlb.h
+++ b/arch/s390/include/asm/tlb.h
@@ -22,98 +22,39 @@
* Pages used for the page tables is a different story. FIXME: more
*/
-#include <linux/mm.h>
-#include <linux/pagemap.h>
-#include <linux/swap.h>
-#include <asm/processor.h>
-#include <asm/pgalloc.h>
-#include <asm/tlbflush.h>
-
-struct mmu_gather {
- struct mm_struct *mm;
- struct mmu_table_batch *batch;
- unsigned int fullmm;
- unsigned long start, end;
-};
-
-struct mmu_table_batch {
- struct rcu_head rcu;
- unsigned int nr;
- void *tables[0];
-};
-
-#define MAX_TABLE_BATCH \
- ((PAGE_SIZE - sizeof(struct mmu_table_batch)) / sizeof(void *))
-
-extern void tlb_table_flush(struct mmu_gather *tlb);
-extern void tlb_remove_table(struct mmu_gather *tlb, void *table);
-
-static inline void
-arch_tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm,
- unsigned long start, unsigned long end)
-{
- tlb->mm = mm;
- tlb->start = start;
- tlb->end = end;
- tlb->fullmm = !(start | (end+1));
- tlb->batch = NULL;
-}
-
-static inline void tlb_flush_mmu_tlbonly(struct mmu_gather *tlb)
-{
- __tlb_flush_mm_lazy(tlb->mm);
-}
-
-static inline void tlb_flush_mmu_free(struct mmu_gather *tlb)
-{
- tlb_table_flush(tlb);
-}
-
+void __tlb_remove_table(void *_table);
+static inline void tlb_flush(struct mmu_gather *tlb);
+static inline bool __tlb_remove_page_size(struct mmu_gather *tlb,
+ struct page *page, int page_size);
-static inline void tlb_flush_mmu(struct mmu_gather *tlb)
-{
- tlb_flush_mmu_tlbonly(tlb);
- tlb_flush_mmu_free(tlb);
-}
+#define tlb_start_vma(tlb, vma) do { } while (0)
+#define tlb_end_vma(tlb, vma) do { } while (0)
-static inline void
-arch_tlb_finish_mmu(struct mmu_gather *tlb,
- unsigned long start, unsigned long end, bool force)
-{
- if (force) {
- tlb->start = start;
- tlb->end = end;
- }
+#define tlb_flush tlb_flush
+#define pte_free_tlb pte_free_tlb
+#define pmd_free_tlb pmd_free_tlb
+#define p4d_free_tlb p4d_free_tlb
+#define pud_free_tlb pud_free_tlb
- tlb_flush_mmu(tlb);
-}
+#include <asm/pgalloc.h>
+#include <asm/tlbflush.h>
+#include <asm-generic/tlb.h>
/*
* Release the page cache reference for a pte removed by
* tlb_ptep_clear_flush. In both flush modes the tlb for a page cache page
* has already been freed, so just do free_page_and_swap_cache.
*/
-static inline bool __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
-{
- free_page_and_swap_cache(page);
- return false; /* avoid calling tlb_flush_mmu */
-}
-
-static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
-{
- free_page_and_swap_cache(page);
-}
-
static inline bool __tlb_remove_page_size(struct mmu_gather *tlb,
struct page *page, int page_size)
{
- return __tlb_remove_page(tlb, page);
+ free_page_and_swap_cache(page);
+ return false;
}
-static inline void tlb_remove_page_size(struct mmu_gather *tlb,
- struct page *page, int page_size)
+static inline void tlb_flush(struct mmu_gather *tlb)
{
- return tlb_remove_page(tlb, page);
+ __tlb_flush_mm_lazy(tlb->mm);
}
/*
@@ -121,9 +62,18 @@ static inline void tlb_remove_page_size(struct mmu_gather *tlb,
* page table from the tlb.
*/
static inline void pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte,
- unsigned long address)
+ unsigned long address)
{
- page_table_free_rcu(tlb, (unsigned long *) pte, address);
+ __tlb_adjust_range(tlb, address, PAGE_SIZE);
+ tlb->mm->context.flush_mm = 1;
+ tlb->freed_tables = 1;
+ tlb->cleared_ptes = 1;
+ /*
+ * page_table_free_rcu takes care of the allocation bit masks
+ * of the 2K table fragments in the 4K page table page,
+ * then calls tlb_remove_table.
+ */
+ page_table_free_rcu(tlb, (unsigned long *) pte, address);
}
/*
@@ -139,6 +89,10 @@ static inline void pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd,
if (tlb->mm->context.asce_limit <= _REGION3_SIZE)
return;
pgtable_pmd_page_dtor(virt_to_page(pmd));
+ __tlb_adjust_range(tlb, address, PAGE_SIZE);
+ tlb->mm->context.flush_mm = 1;
+ tlb->freed_tables = 1;
+ tlb->cleared_puds = 1;
tlb_remove_table(tlb, pmd);
}
@@ -154,6 +108,10 @@ static inline void p4d_free_tlb(struct mmu_gather *tlb, p4d_t *p4d,
{
if (tlb->mm->context.asce_limit <= _REGION1_SIZE)
return;
+ __tlb_adjust_range(tlb, address, PAGE_SIZE);
+ tlb->mm->context.flush_mm = 1;
+ tlb->freed_tables = 1;
+ tlb->cleared_p4ds = 1;
tlb_remove_table(tlb, p4d);
}
@@ -169,19 +127,11 @@ static inline void pud_free_tlb(struct mmu_gather *tlb, pud_t *pud,
{
if (tlb->mm->context.asce_limit <= _REGION2_SIZE)
return;
+ tlb->mm->context.flush_mm = 1;
+ tlb->freed_tables = 1;
+ tlb->cleared_puds = 1;
tlb_remove_table(tlb, pud);
}
-#define tlb_start_vma(tlb, vma) do { } while (0)
-#define tlb_end_vma(tlb, vma) do { } while (0)
-#define tlb_remove_tlb_entry(tlb, ptep, addr) do { } while (0)
-#define tlb_remove_pmd_tlb_entry(tlb, pmdp, addr) do { } while (0)
-#define tlb_migrate_finish(mm) do { } while (0)
-#define tlb_remove_huge_tlb_entry(h, tlb, ptep, address) \
- tlb_remove_tlb_entry(tlb, ptep, address)
-
-static inline void tlb_change_page_size(struct mmu_gather *tlb, unsigned int page_size)
-{
-}
#endif /* _S390_TLB_H */
diff --git a/arch/s390/mm/pgalloc.c b/arch/s390/mm/pgalloc.c
index 76d89ee8b428..f7656a0b3a1a 100644
--- a/arch/s390/mm/pgalloc.c
+++ b/arch/s390/mm/pgalloc.c
@@ -288,7 +288,7 @@ void page_table_free_rcu(struct mmu_gather *tlb, unsigned long *table,
tlb_remove_table(tlb, table);
}
-static void __tlb_remove_table(void *_table)
+void __tlb_remove_table(void *_table)
{
unsigned int mask = (unsigned long) _table & 3;
void *table = (void *)((unsigned long) _table ^ mask);
@@ -314,67 +314,6 @@ static void __tlb_remove_table(void *_table)
}
}
-static void tlb_remove_table_smp_sync(void *arg)
-{
- /* Simply deliver the interrupt */
-}
-
-static void tlb_remove_table_one(void *table)
-{
- /*
- * This isn't an RCU grace period and hence the page-tables cannot be
- * assumed to be actually RCU-freed.
- *
- * It is however sufficient for software page-table walkers that rely
- * on IRQ disabling. See the comment near struct mmu_table_batch.
- */
- smp_call_function(tlb_remove_table_smp_sync, NULL, 1);
- __tlb_remove_table(table);
-}
-
-static void tlb_remove_table_rcu(struct rcu_head *head)
-{
- struct mmu_table_batch *batch;
- int i;
-
- batch = container_of(head, struct mmu_table_batch, rcu);
-
- for (i = 0; i < batch->nr; i++)
- __tlb_remove_table(batch->tables[i]);
-
- free_page((unsigned long)batch);
-}
-
-void tlb_table_flush(struct mmu_gather *tlb)
-{
- struct mmu_table_batch **batch = &tlb->batch;
-
- if (*batch) {
- call_rcu_sched(&(*batch)->rcu, tlb_remove_table_rcu);
- *batch = NULL;
- }
-}
-
-void tlb_remove_table(struct mmu_gather *tlb, void *table)
-{
- struct mmu_table_batch **batch = &tlb->batch;
-
- tlb->mm->context.flush_mm = 1;
- if (*batch == NULL) {
- *batch = (struct mmu_table_batch *)
- __get_free_page(GFP_NOWAIT | __GFP_NOWARN);
- if (*batch == NULL) {
- __tlb_flush_mm_lazy(tlb->mm);
- tlb_remove_table_one(table);
- return;
- }
- (*batch)->nr = 0;
- }
- (*batch)->tables[(*batch)->nr++] = table;
- if ((*batch)->nr == MAX_TABLE_BATCH)
- tlb_flush_mmu(tlb);
-}
-
/*
* Base infrastructure required to generate basic asces, region, segment,
* and page tables that do not make use of enhanced features like EDAT1.
--
2.16.4
^ permalink raw reply related [flat|nested] 6+ messages in thread