From: Laurent Dufour <ldufour@linux.vnet.ibm.com>
To: paulmck@linux.vnet.ibm.com, peterz@infradead.org,
akpm@linux-foundation.org, kirill@shutemov.name,
ak@linux.intel.com, mhocko@kernel.org, dave@stgolabs.net,
jack@suse.cz, Matthew Wilcox <willy@infradead.org>,
benh@kernel.crashing.org, mpe@ellerman.id.au, paulus@samba.org,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
hpa@zytor.com, Will Deacon <will.deacon@arm.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
haren@linux.vnet.ibm.com, khandual@linux.vnet.ibm.com,
npiggin@gmail.com, bsingharora@gmail.com,
Tim Chen <tim.c.chen@linux.intel.com>,
linuxppc-dev@lists.ozlabs.org, x86@kernel.org
Subject: [PATCH v2 04/20] mm: VMA sequence count
Date: Fri, 18 Aug 2017 00:05:03 +0200 [thread overview]
Message-ID: <1503007519-26777-5-git-send-email-ldufour@linux.vnet.ibm.com> (raw)
In-Reply-To: <1503007519-26777-1-git-send-email-ldufour@linux.vnet.ibm.com>
From: Peter Zijlstra <peterz@infradead.org>
Wrap the VMA modifications (vma_adjust/unmap_page_range) with sequence
counts such that we can easily test if a VMA is changed.
The unmap_page_range() one allows us to make assumptions about
page-tables; when we find the seqcount hasn't changed we can assume
page-tables are still valid.
The flip side is that we cannot distinguish between a vma_adjust() and
the unmap_page_range() -- where with the former we could have
re-checked the vma bounds against the address.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
[Port to 4.12 kernel]
[Fix lock dependency between mapping->i_mmap_rwsem and vma->vm_sequence]
Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
---
include/linux/mm_types.h | 1 +
mm/memory.c | 2 ++
mm/mmap.c | 21 ++++++++++++++++++---
3 files changed, 21 insertions(+), 3 deletions(-)
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 3cadee0a3508..642aad26b32f 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -342,6 +342,7 @@ struct vm_area_struct {
struct mempolicy *vm_policy; /* NUMA policy for the VMA */
#endif
struct vm_userfaultfd_ctx vm_userfaultfd_ctx;
+ seqcount_t vm_sequence;
} __randomize_layout;
struct core_thread {
diff --git a/mm/memory.c b/mm/memory.c
index fa598889eb0e..4a2736fe2ef6 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1408,6 +1408,7 @@ void unmap_page_range(struct mmu_gather *tlb,
unsigned long next;
BUG_ON(addr >= end);
+ write_seqcount_begin(&vma->vm_sequence);
tlb_start_vma(tlb, vma);
pgd = pgd_offset(vma->vm_mm, addr);
do {
@@ -1417,6 +1418,7 @@ void unmap_page_range(struct mmu_gather *tlb,
next = zap_p4d_range(tlb, vma, pgd, addr, next, details);
} while (pgd++, addr = next, addr != end);
tlb_end_vma(tlb, vma);
+ write_seqcount_end(&vma->vm_sequence);
}
diff --git a/mm/mmap.c b/mm/mmap.c
index f19efcf75418..140b22136cb7 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -557,6 +557,8 @@ void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma,
else
mm->highest_vm_end = vm_end_gap(vma);
+ seqcount_init(&vma->vm_sequence);
+
/*
* vma->vm_prev wasn't known when we followed the rbtree to find the
* correct insertion point for that vma. As a result, we could not
@@ -798,6 +800,11 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
}
}
+ write_seqcount_begin(&vma->vm_sequence);
+ if (next && next != vma)
+ write_seqcount_begin_nested(&next->vm_sequence,
+ SINGLE_DEPTH_NESTING);
+
anon_vma = vma->anon_vma;
if (!anon_vma && adjust_next)
anon_vma = next->anon_vma;
@@ -902,6 +909,7 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
mm->map_count--;
mpol_put(vma_policy(next));
kmem_cache_free(vm_area_cachep, next);
+ write_seqcount_end(&next->vm_sequence);
/*
* In mprotect's case 6 (see comments on vma_merge),
* we must remove another next too. It would clutter
@@ -931,11 +939,14 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
if (remove_next == 2) {
remove_next = 1;
end = next->vm_end;
+ write_seqcount_end(&vma->vm_sequence);
goto again;
- }
- else if (next)
+ } else if (next) {
+ if (next != vma)
+ write_seqcount_begin_nested(&next->vm_sequence,
+ SINGLE_DEPTH_NESTING);
vma_gap_update(next);
- else {
+ } else {
/*
* If remove_next == 2 we obviously can't
* reach this path.
@@ -961,6 +972,10 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
if (insert && file)
uprobe_mmap(insert);
+ if (next && next != vma)
+ write_seqcount_end(&next->vm_sequence);
+ write_seqcount_end(&vma->vm_sequence);
+
validate_mm(mm);
return 0;
--
2.7.4
next prev parent reply other threads:[~2017-08-17 22:05 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-17 22:04 [PATCH v2 00/20] Speculative page faults Laurent Dufour
2017-08-17 22:05 ` [PATCH v2 01/20] mm: Dont assume page-table invariance during faults Laurent Dufour
2017-08-17 22:05 ` [PATCH v2 02/20] mm: Prepare for FAULT_FLAG_SPECULATIVE Laurent Dufour
2017-08-17 22:05 ` [PATCH v2 03/20] mm: Introduce pte_spinlock " Laurent Dufour
2017-08-17 22:05 ` Laurent Dufour [this message]
2017-08-17 22:05 ` [PATCH v2 05/20] mm: Protect VMA modifications using VMA sequence count Laurent Dufour
2017-08-17 22:05 ` [PATCH v2 06/20] mm: RCU free VMAs Laurent Dufour
2017-08-17 22:05 ` [PATCH v2 07/20] mm: Cache some VMA fields in the vm_fault structure Laurent Dufour
2017-08-17 22:05 ` [PATCH v2 08/20] mm: Protect SPF handler against anon_vma changes Laurent Dufour
2017-08-17 22:05 ` [PATCH v2 09/20] mm/migrate: Pass vm_fault pointer to migrate_misplaced_page() Laurent Dufour
2017-08-17 22:05 ` [PATCH v2 10/20] mm: Introduce __lru_cache_add_active_or_unevictable Laurent Dufour
2017-08-17 22:05 ` [PATCH v2 11/20] mm: Introduce __maybe_mkwrite() Laurent Dufour
2017-08-17 22:05 ` [PATCH v2 12/20] mm: Introduce __vm_normal_page() Laurent Dufour
2017-08-17 22:05 ` [PATCH v2 13/20] mm: Introduce __page_add_new_anon_rmap() Laurent Dufour
2017-08-17 22:05 ` [PATCH v2 14/20] mm: Provide speculative fault infrastructure Laurent Dufour
2017-08-20 12:11 ` Sergey Senozhatsky
2017-08-25 8:52 ` Laurent Dufour
2017-08-27 0:18 ` Kirill A. Shutemov
2017-08-28 9:37 ` Peter Zijlstra
2017-08-28 21:14 ` Benjamin Herrenschmidt
2017-08-28 22:35 ` Andi Kleen
2017-08-29 8:15 ` Peter Zijlstra
2017-08-29 8:33 ` Peter Zijlstra
2017-08-29 11:27 ` Peter Zijlstra
2017-08-29 21:19 ` Benjamin Herrenschmidt
2017-08-30 6:13 ` Peter Zijlstra
2017-08-29 7:59 ` Laurent Dufour
2017-08-29 12:04 ` Peter Zijlstra
2017-08-29 13:18 ` Laurent Dufour
2017-08-29 13:45 ` Peter Zijlstra
2017-08-30 5:03 ` Anshuman Khandual
2017-08-30 5:58 ` Peter Zijlstra
2017-08-30 9:32 ` Laurent Dufour
2017-08-31 6:55 ` Anshuman Khandual
2017-08-31 7:31 ` Peter Zijlstra
2017-08-30 9:53 ` Laurent Dufour
2017-08-30 3:48 ` Anshuman Khandual
2017-08-30 5:25 ` Anshuman Khandual
2017-08-30 8:56 ` Laurent Dufour
2017-08-17 22:05 ` [PATCH v2 15/20] mm: Try spin lock in speculative path Laurent Dufour
2017-08-17 22:05 ` [PATCH v2 16/20] mm: Adding speculative page fault failure trace events Laurent Dufour
2017-08-17 22:05 ` [PATCH v2 17/20] perf: Add a speculative page fault sw event Laurent Dufour
2017-08-21 8:55 ` Anshuman Khandual
2017-08-22 1:46 ` Michael Ellerman
2017-08-17 22:05 ` [PATCH v2 18/20] perf tools: Add support for the SPF perf event Laurent Dufour
2017-08-21 8:48 ` Anshuman Khandual
2017-08-25 8:53 ` Laurent Dufour
2017-08-17 22:05 ` [PATCH v2 19/20] x86/mm: Add speculative pagefault handling Laurent Dufour
2017-08-21 7:29 ` Anshuman Khandual
2017-08-29 14:50 ` Laurent Dufour
2017-08-29 14:58 ` Laurent Dufour
2017-08-17 22:05 ` [PATCH v2 20/20] powerpc/mm: Add speculative page fault Laurent Dufour
2017-08-21 6:58 ` Anshuman Khandual
2017-08-29 15:13 ` Laurent Dufour
2017-08-21 2:26 ` [PATCH v2 00/20] Speculative page faults Sergey Senozhatsky
2017-09-08 9:24 ` Laurent Dufour
2017-09-11 0:45 ` Sergey Senozhatsky
2017-09-11 6:28 ` Laurent Dufour
2017-08-21 6:28 ` Anshuman Khandual
2017-08-22 0:41 ` Paul E. McKenney
2017-08-25 9:41 ` Laurent Dufour
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