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Subject[PATCH 02/13] mm/rmap: update to new mmu_notifier semantic v2
Date
From: Jérôme Glisse <jglisse@redhat.com>

Replacing all mmu_notifier_invalidate_page() by mmu_notifier_invalidat_range()
and making sure it is bracketed by call to mmu_notifier_invalidate_range_start/
end.

Note that because we can not presume the pmd value or pte value we have to
assume the worse and unconditionaly report an invalidation as happening.

Changed since v2:
- try_to_unmap_one() only one call to mmu_notifier_invalidate_range()
- compute end with PAGE_SIZE << compound_order(page)
- fix PageHuge() case in try_to_unmap_one()

Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Bernhard Held <berny156@gmx.de>
Cc: Adam Borowski <kilobyte@angband.pl>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Wanpeng Li <kernellwp@gmail.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: axie <axie@amd.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
---
mm/rmap.c | 35 ++++++++++++++++++++++++++++++++---
1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/mm/rmap.c b/mm/rmap.c
index c8993c63eb25..c570f82e6827 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -887,11 +887,21 @@ static bool page_mkclean_one(struct page *page, struct vm_area_struct *vma,
.address = address,
.flags = PVMW_SYNC,
};
+ unsigned long start = address, end;
int *cleaned = arg;

+ /*
+ * We have to assume the worse case ie pmd for invalidation. Note that
+ * the page can not be free from this function.
+ */
+ end = min(vma->vm_end, start + (PAGE_SIZE << compound_order(page)));
+ mmu_notifier_invalidate_range_start(vma->vm_mm, start, end);
+
while (page_vma_mapped_walk(&pvmw)) {
+ unsigned long cstart, cend;
int ret = 0;
- address = pvmw.address;
+
+ cstart = address = pvmw.address;
if (pvmw.pte) {
pte_t entry;
pte_t *pte = pvmw.pte;
@@ -904,6 +914,7 @@ static bool page_mkclean_one(struct page *page, struct vm_area_struct *vma,
entry = pte_wrprotect(entry);
entry = pte_mkclean(entry);
set_pte_at(vma->vm_mm, address, pte, entry);
+ cend = cstart + PAGE_SIZE;
ret = 1;
} else {
#ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
@@ -918,6 +929,8 @@ static bool page_mkclean_one(struct page *page, struct vm_area_struct *vma,
entry = pmd_wrprotect(entry);
entry = pmd_mkclean(entry);
set_pmd_at(vma->vm_mm, address, pmd, entry);
+ cstart &= PMD_MASK;
+ cend = cstart + PMD_SIZE;
ret = 1;
#else
/* unexpected pmd-mapped page? */
@@ -926,11 +939,13 @@ static bool page_mkclean_one(struct page *page, struct vm_area_struct *vma,
}

if (ret) {
- mmu_notifier_invalidate_page(vma->vm_mm, address);
+ mmu_notifier_invalidate_range(vma->vm_mm, cstart, cend);
(*cleaned)++;
}
}

+ mmu_notifier_invalidate_range_end(vma->vm_mm, start, end);
+
return true;
}

@@ -1324,6 +1339,7 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
pte_t pteval;
struct page *subpage;
bool ret = true;
+ unsigned long start = address, end;
enum ttu_flags flags = (enum ttu_flags)arg;

/* munlock has nothing to gain from examining un-locked vmas */
@@ -1335,6 +1351,14 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
flags & TTU_MIGRATION, page);
}

+ /*
+ * We have to assume the worse case ie pmd for invalidation. Note that
+ * the page can not be free in this function as call of try_to_unmap()
+ * must hold a reference on the page.
+ */
+ end = min(vma->vm_end, start + (PAGE_SIZE << compound_order(page)));
+ mmu_notifier_invalidate_range_start(vma->vm_mm, start, end);
+
while (page_vma_mapped_walk(&pvmw)) {
/*
* If the page is mlock()d, we cannot swap it out.
@@ -1445,6 +1469,7 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
if (unlikely(PageSwapBacked(page) != PageSwapCache(page))) {
WARN_ON_ONCE(1);
ret = false;
+ /* We have to invalidate as we cleared the pte */
page_vma_mapped_walk_done(&pvmw);
break;
}
@@ -1490,8 +1515,12 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
discard:
page_remove_rmap(subpage, PageHuge(page));
put_page(page);
- mmu_notifier_invalidate_page(mm, address);
+ mmu_notifier_invalidate_range(mm, address,
+ address + PAGE_SIZE);
}
+
+ mmu_notifier_invalidate_range_end(vma->vm_mm, start, end);
+
return ret;
}

--
2.13.5
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