Commit 7eef5f97 authored by Andrea Arcangeli's avatar Andrea Arcangeli Committed by Linus Torvalds

mm: thp: relocate flush_cache_range() in migrate_misplaced_transhuge_page()

There should be no cache left by the time we overwrite the old transhuge
pmd with the new one.  It's already too late to flush through the virtual
address because we already copied the page data to the new physical
address.

So flush the cache before the data copy.

Also delete the "end" variable to shutoff a "unused variable" warning on
x86 where flush_cache_range() is a noop.

Link: http://lkml.kernel.org/r/20181015202311.7209-1-aarcange@redhat.comSigned-off-by: default avatarAndrea Arcangeli <aarcange@redhat.com>
Acked-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Aaron Tomlin <atomlin@redhat.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 7066f0f9
......@@ -1976,7 +1976,6 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm,
struct page *new_page = NULL;
int page_lru = page_is_file_cache(page);
unsigned long start = address & HPAGE_PMD_MASK;
unsigned long end = start + HPAGE_PMD_SIZE;
new_page = alloc_pages_node(node,
(GFP_TRANSHUGE_LIGHT | __GFP_THISNODE),
......@@ -1999,6 +1998,8 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm,
/* anon mapping, we can simply copy page->mapping to the new page: */
new_page->mapping = page->mapping;
new_page->index = page->index;
/* flush the cache before copying using the kernel virtual address */
flush_cache_range(vma, start, start + HPAGE_PMD_SIZE);
migrate_page_copy(new_page, page);
WARN_ON(PageLRU(new_page));
......@@ -2036,7 +2037,6 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm,
* new page and page_add_new_anon_rmap guarantee the copy is
* visible before the pagetable update.
*/
flush_cache_range(vma, start, end);
page_add_anon_rmap(new_page, vma, start, true);
/*
* At this point the pmd is numa/protnone (i.e. non present) and the TLB
......
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