The patch titled
Subject: mm: get 7% more pages in a pagevec
has been added to the -mm tree. Its filename is
get-7%-more-pages-in-a-pagevec.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/get-7%25-more-pages-in-a-pagevec.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/get-7%25-more-pages-in-a-pagevec.patch
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------------------------------------------------------
From: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Subject: mm: get 7% more pages in a pagevec
We don't have to use an entire 'long' for the number of elements in the
pagevec; we know it's a number between 0 and 14 (now 15). So we can store
it in a char, and then the bool packs next to it and we still have two or
six bytes of padding for more elements in the header. That gives us space
to cram in an extra page.
Link: http://lkml.kernel.org/r/20171206022521.GM26021@xxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/pagevec.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff -puN include/linux/pagevec.h~get-7%-more-pages-in-a-pagevec include/linux/pagevec.h
--- a/include/linux/pagevec.h~get-7%-more-pages-in-a-pagevec
+++ a/include/linux/pagevec.h
@@ -9,14 +9,14 @@
#ifndef _LINUX_PAGEVEC_H
#define _LINUX_PAGEVEC_H
-/* 14 pointers + two long's align the pagevec structure to a power of two */
-#define PAGEVEC_SIZE 14
+/* 15 pointers + header align the pagevec structure to a power of two */
+#define PAGEVEC_SIZE 15
struct page;
struct address_space;
struct pagevec {
- unsigned long nr;
+ unsigned char nr;
bool percpu_pvec_drained;
struct page *pages[PAGEVEC_SIZE];
};
_
Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are
mm-add-unmap_mapping_pages.patch
get-7%-more-pages-in-a-pagevec.patch
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