From: "Matthew Wilcox (Oracle)" willy@infradead.org
mainline inclusion from mainline-v6.9-rc2 commit 9cecde80aae0fb0aa44425575d5aca71bc646d89 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I9R3AY CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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On a 104 thread, 2 socket Skylake system, Intel report a 4.7% performance reduction with will-it-scale page_fault2. This was due to reducing the size of the batch from 32 to 15. Increasing the folio batch size from 15 to 31 gives a performance increase of 12.5% relative to the original, or 17.2% relative to the reduced performance commit.
The penalty of this commit is an additional 128 bytes of stack usage. Six folio_batches are also allocated from percpu memory in cpu_fbatches so that will be an additional 768 bytes of percpu memory (per CPU). Tim Chen originally submitted a patch like this in 2020: https://lore.kernel.org/linux-mm/d1cc9f12a8ad6c2a52cb600d93b06b064f2bbc57.15...
Link: https://lkml.kernel.org/r/20240315140823.2478146-1-willy@infradead.org Fixes: 99fbb6bfc16f ("mm: make folios_put() the basis of release_pages()") Signed-off-by: Matthew Wilcox (Oracle) willy@infradead.org Tested-by: Yujie Liu yujie.liu@intel.com Reported-by: kernel test robot oliver.sang@intel.com Closes: https://lore.kernel.org/oe-lkp/202403151058.7048f6a8-oliver.sang@intel.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Liu Shixin liushixin2@huawei.com --- include/linux/pagevec.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/linux/pagevec.h b/include/linux/pagevec.h index 87cc678adc85..67f10b8810a8 100644 --- a/include/linux/pagevec.h +++ b/include/linux/pagevec.h @@ -11,8 +11,8 @@
#include <linux/types.h>
-/* 15 pointers + header align the folio_batch structure to a power of two */ -#define PAGEVEC_SIZE 15 +/* 31 pointers + header align the folio_batch structure to a power of two */ +#define PAGEVEC_SIZE 31
struct folio;