diff options
author | Otavio Salvador <otavio@ossystems.com.br> | 2019-03-28 10:47:24 -0300 |
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committer | GitHub <noreply@github.com> | 2019-03-28 10:47:24 -0300 |
commit | 0a8ab17689e628c84a666195bfc6ab85d11cf057 (patch) | |
tree | 01630dc4a6935df99bf7d11d34ff8d384fed86e2 /mm/memory.c | |
parent | 1e71d8c630cbc0d1f5d762fd019690b5cdb880ae (diff) | |
parent | 32aca03c2ce868d3412da0bb6ce6798c7bea357e (diff) |
Merge pull request #46 from toradex/4.9-2.3.x-imx
4.9 2.3.x imx
Diffstat (limited to 'mm/memory.c')
-rw-r--r-- | mm/memory.c | 43 |
1 files changed, 37 insertions, 6 deletions
diff --git a/mm/memory.c b/mm/memory.c index f3fef1df7402..47248dc0b9e1 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2823,6 +2823,28 @@ static int __do_fault(struct fault_env *fe, pgoff_t pgoff, struct vm_fault vmf; int ret; + /* + * Preallocate pte before we take page_lock because this might lead to + * deadlocks for memcg reclaim which waits for pages under writeback: + * lock_page(A) + * SetPageWriteback(A) + * unlock_page(A) + * lock_page(B) + * lock_page(B) + * pte_alloc_pne + * shrink_page_list + * wait_on_page_writeback(A) + * SetPageWriteback(B) + * unlock_page(B) + * # flush A, B to clear the writeback + */ + if (pmd_none(*fe->pmd) && !fe->prealloc_pte) { + fe->prealloc_pte = pte_alloc_one(vma->vm_mm, fe->address); + if (!fe->prealloc_pte) + return VM_FAULT_OOM; + smp_wmb(); /* See comment in __pte_alloc() */ + } + vmf.virtual_address = (void __user *)(fe->address & PAGE_MASK); vmf.pgoff = pgoff; vmf.flags = fe->flags; @@ -3307,15 +3329,24 @@ static int do_fault(struct fault_env *fe) { struct vm_area_struct *vma = fe->vma; pgoff_t pgoff = linear_page_index(vma, fe->address); + int ret; /* The VMA was not fully populated on mmap() or missing VM_DONTEXPAND */ if (!vma->vm_ops->fault) - return VM_FAULT_SIGBUS; - if (!(fe->flags & FAULT_FLAG_WRITE)) - return do_read_fault(fe, pgoff); - if (!(vma->vm_flags & VM_SHARED)) - return do_cow_fault(fe, pgoff); - return do_shared_fault(fe, pgoff); + ret = VM_FAULT_SIGBUS; + else if (!(fe->flags & FAULT_FLAG_WRITE)) + ret = do_read_fault(fe, pgoff); + else if (!(vma->vm_flags & VM_SHARED)) + ret = do_cow_fault(fe, pgoff); + else + ret = do_shared_fault(fe, pgoff); + + /* preallocated pagetable is unused: free it */ + if (fe->prealloc_pte) { + pte_free(vma->vm_mm, fe->prealloc_pte); + fe->prealloc_pte = 0; + } + return ret; } static int numa_migrate_prep(struct page *page, struct vm_area_struct *vma, |