From 0719fdba54836b6d7acbe7d74f81df2153a40810 Mon Sep 17 00:00:00 2001 From: Yixuan Cao Date: Wed, 5 Oct 2022 22:55:25 +0800 Subject: [PATCH] Documentation/mm/page_owner.rst: delete frequently changing experimental data The kernel size changes due to many factors, such as compiler version, configuration, and the build environment. This makes size comparison figures irrelevant to reader's setup. Remove these figures and describe the effects of page owner to the kernel size in general instead. Thanks for Jonathan Corbet, Bagas Sanjaya and Mike Rapoport's constructive suggestions. Signed-off-by: Yixuan Cao Link: https://lore.kernel.org/r/20221005145525.10359-1-caoyixuan2019@email.szu.edu.cn Signed-off-by: Jonathan Corbet --- Documentation/mm/page_owner.rst | 20 ++++---------------- 1 file changed, 4 insertions(+), 16 deletions(-) diff --git a/Documentation/mm/page_owner.rst b/Documentation/mm/page_owner.rst index f5c954afe97c..f1efbb414ea6 100644 --- a/Documentation/mm/page_owner.rst +++ b/Documentation/mm/page_owner.rst @@ -38,22 +38,10 @@ not affect to allocation performance, especially if the static keys jump label patching functionality is available. Following is the kernel's code size change due to this facility. -- Without page owner:: - - text data bss dec hex filename - 48392 2333 644 51369 c8a9 mm/page_alloc.o - -- With page owner:: - - text data bss dec hex filename - 48800 2445 644 51889 cab1 mm/page_alloc.o - 6662 108 29 6799 1a8f mm/page_owner.o - 1025 8 8 1041 411 mm/page_ext.o - -Although, roughly, 8 KB code is added in total, page_alloc.o increase by -520 bytes and less than half of it is in hotpath. Building the kernel with -page owner and turning it on if needed would be great option to debug -kernel memory problem. +Although enabling page owner increases kernel size by several kilobytes, +most of this code is outside page allocator and its hot path. Building +the kernel with page owner and turning it on if needed would be great +option to debug kernel memory problem. There is one notice that is caused by implementation detail. page owner stores information into the memory from struct page extension. This memory