Subject: + mm-introduce-do_cow_fault.patch added to -mm tree
To: kirill.shutemov@xxxxxxxxxxxxxxx,ak@xxxxxxxxxxxxxxx,dave.hansen@xxxxxxxxxxxxxxx,matthew.r.wilcox@xxxxxxxxx,mgorman@xxxxxxx,n-horiguchi@xxxxxxxxxxxxx,riel@xxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Mon, 10 Feb 2014 14:54:09 -0800
The patch titled
Subject: mm: introduce do_cow_fault()
has been added to the -mm tree. Its filename is
mm-introduce-do_cow_fault.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-introduce-do_cow_fault.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-introduce-do_cow_fault.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Subject: mm: introduce do_cow_fault()
Introduce do_cow_fault(). The function does what do_fault() does for
write page faults to private mappings.
Unlike do_fault(), do_read_fault() is relatively clean and
straight-forward.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Matthew Wilcox <matthew.r.wilcox@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 62 insertions(+)
diff -puN mm/memory.c~mm-introduce-do_cow_fault mm/memory.c
--- a/mm/memory.c~mm-introduce-do_cow_fault
+++ a/mm/memory.c
@@ -3354,6 +3354,62 @@ static int do_read_fault(struct mm_struc
return ret;
}
+static int do_cow_fault(struct mm_struct *mm, struct vm_area_struct *vma,
+ unsigned long address, pmd_t *pmd,
+ pgoff_t pgoff, unsigned int flags, pte_t orig_pte)
+{
+ struct page *fault_page, *new_page;
+ spinlock_t *ptl;
+ pte_t entry, *pte;
+ int ret;
+
+ if (unlikely(anon_vma_prepare(vma)))
+ return VM_FAULT_OOM;
+
+ new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
+ if (!new_page)
+ return VM_FAULT_OOM;
+
+ if (mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL)) {
+ page_cache_release(new_page);
+ return VM_FAULT_OOM;
+ }
+
+ ret = __do_fault(vma, address, pgoff, flags, &fault_page);
+ if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
+ goto uncharge_out;
+
+ copy_user_highpage(new_page, fault_page, address, vma);
+ __SetPageUptodate(new_page);
+
+ pte = pte_offset_map_lock(mm, pmd, address, &ptl);
+ if (unlikely(!pte_same(*pte, orig_pte))) {
+ pte_unmap_unlock(pte, ptl);
+ unlock_page(fault_page);
+ page_cache_release(fault_page);
+ goto uncharge_out;
+ }
+
+ flush_icache_page(vma, new_page);
+ entry = mk_pte(new_page, vma->vm_page_prot);
+ entry = maybe_mkwrite(pte_mkdirty(entry), vma);
+ inc_mm_counter_fast(mm, MM_ANONPAGES);
+ page_add_new_anon_rmap(new_page, vma, address);
+ set_pte_at(mm, address, pte, entry);
+
+ /* no need to invalidate: a not-present page won't be cached */
+ update_mmu_cache(vma, address, pte);
+
+ pte_unmap_unlock(pte, ptl);
+ unlock_page(fault_page);
+ page_cache_release(fault_page);
+ return ret;
+uncharge_out:
+ mem_cgroup_uncharge_page(new_page);
+ page_cache_release(new_page);
+ return ret;
+}
+
/*
* do_fault() tries to create a new page mapping. It aggressively
* tries to share with existing pages, but makes a separate copy if
@@ -3550,6 +3606,9 @@ static int do_linear_fault(struct mm_str
if (!(flags & FAULT_FLAG_WRITE))
return do_read_fault(mm, vma, address, pmd, pgoff, flags,
orig_pte);
+ if (!(vma->vm_flags & VM_SHARED))
+ return do_cow_fault(mm, vma, address, pmd, pgoff, flags,
+ orig_pte);
return do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
}
@@ -3585,6 +3644,9 @@ static int do_nonlinear_fault(struct mm_
if (!(flags & FAULT_FLAG_WRITE))
return do_read_fault(mm, vma, address, pmd, pgoff, flags,
orig_pte);
+ if (!(vma->vm_flags & VM_SHARED))
+ return do_cow_fault(mm, vma, address, pmd, pgoff, flags,
+ orig_pte);
return do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
}
_
Patches currently in -mm which might be from kirill.shutemov@xxxxxxxxxxxxxxx are
pagewalk-update-page-table-walker-core.patch
pagewalk-add-walk_page_vma.patch
smaps-redefine-callback-functions-for-page-table-walker.patch
clear_refs-redefine-callback-functions-for-page-table-walker.patch
pagemap-redefine-callback-functions-for-page-table-walker.patch
numa_maps-redefine-callback-functions-for-page-table-walker.patch
memcg-redefine-callback-functions-for-page-table-walker.patch
madvise-redefine-callback-functions-for-page-table-walker.patch
arch-powerpc-mm-subpage-protc-use-walk_page_vma-instead-of-walk_page_range.patch
pagewalk-remove-argument-hmask-from-hugetlb_entry.patch
mempolicy-apply-page-table-walker-on-queue_pages_range.patch
mm-hwpoison-release-page-on-pagehwpoison-in-__do_fault.patch
mm-rename-__do_fault-do_fault.patch
mm-do_fault-extract-to-call-vm_ops-do_fault-to-separate-function.patch
mm-introduce-do_read_fault.patch
mm-introduce-do_cow_fault.patch
mm-introduce-do_shared_fault-and-drop-do_fault.patch
mm-consolidate-code-to-call-vm_ops-page_mkwrite.patch
mm-consolidate-code-to-setup-pte.patch
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