The patch titled
Subject: mm: thp: relocate flush_cache_range() in migrate_misplaced_transhuge_page()
has been added to the -mm tree. Its filename is
mm-thp-relocate-flush_cache_range-in-migrate_misplaced_transhuge_page.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-thp-relocate-flush_cache_range-in-migrate_misplaced_transhuge_page.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-thp-relocate-flush_cache_range-in-migrate_misplaced_transhuge_page.patch
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------------------------------------------------------
From: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Subject: 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@xxxxxxxxxx
Signed-off-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Aaron Tomlin <atomlin@xxxxxxxxxx>
Cc: Jerome Glisse <jglisse@xxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/migrate.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/mm/migrate.c~mm-thp-relocate-flush_cache_range-in-migrate_misplaced_transhuge_page
+++ a/mm/migrate.c
@@ -1976,7 +1976,6 @@ int migrate_misplaced_transhuge_page(str
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(str
/* 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(str
* 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)
_
Patches currently in -mm which might be from aarcange@xxxxxxxxxx are
mm-thp-relax-__gfp_thisnode-for-madv_hugepage-mappings.patch
userfaultfd-allow-get_mempolicympol_f_nodempol_f_addr-to-trigger-userfaults.patch
mm-thp-fix-madv_dontneed-vs-migrate_misplaced_transhuge_page-race-condition.patch
mm-thp-fix-mmu_notifier-in-migrate_misplaced_transhuge_page.patch
mm-thp-relocate-flush_cache_range-in-migrate_misplaced_transhuge_page.patch
