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authorMatthew Wilcox (Oracle) <willy@infradead.org>2020-08-15 02:30:23 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2020-08-15 04:56:56 +0200
commit1378a5ee451a5e87d0d8dd6356a0b7844db231f6 (patch)
tree557c87581ebd5347545d5bf86c5b6711f846b341 /mm
parentmailmap: add entry for Greg Kurz (diff)
downloadlinux-1378a5ee451a5e87d0d8dd6356a0b7844db231f6.tar.xz
linux-1378a5ee451a5e87d0d8dd6356a0b7844db231f6.zip
mm: store compound_nr as well as compound_order
Patch series "THP prep patches". These are some generic cleanups and improvements, which I would like merged into mmotm soon. The first one should be a performance improvement for all users of compound pages, and the others are aimed at getting code to compile away when CONFIG_TRANSPARENT_HUGEPAGE is disabled (ie small systems). Also better documented / less confusing than the current prefix mixture of compound, hpage and thp. This patch (of 7): This removes a few instructions from functions which need to know how many pages are in a compound page. The storage used is either page->mapping on 64-bit or page->index on 32-bit. Both of these are fine to overlay on tail pages. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: William Kucharski <william.kucharski@oracle.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Cc: David Hildenbrand <david@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Link: http://lkml.kernel.org/r/20200629151959.15779-1-willy@infradead.org Link: http://lkml.kernel.org/r/20200629151959.15779-2-willy@infradead.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/page_alloc.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 8b7d0ecf30b1..0e2bab486fea 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -666,8 +666,6 @@ void prep_compound_page(struct page *page, unsigned int order)
int i;
int nr_pages = 1 << order;
- set_compound_page_dtor(page, COMPOUND_PAGE_DTOR);
- set_compound_order(page, order);
__SetPageHead(page);
for (i = 1; i < nr_pages; i++) {
struct page *p = page + i;
@@ -675,6 +673,9 @@ void prep_compound_page(struct page *page, unsigned int order)
p->mapping = TAIL_MAPPING;
set_compound_head(p, page);
}
+
+ set_compound_page_dtor(page, COMPOUND_PAGE_DTOR);
+ set_compound_order(page, order);
atomic_set(compound_mapcount_ptr(page), -1);
if (hpage_pincount_available(page))
atomic_set(compound_pincount_ptr(page), 0);