Buildresult: linus/generic-32bit_defconfig/parisc-gcc8 built on Nov 27 2020, 07:04
kisskb
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Status:
OK
Date/Time:
Nov 27 2020, 07:04
Duration:
0:01:09.875271
Builder:
ka4
Revision:
mm: memcg: relayout structure mem_cgroup to avoid cache interference (
4df910620bebb5cfe234af16ac8f6474b60215fd)
Target:
linus/generic-32bit_defconfig/parisc-gcc8
Branch:
linus
Compiler:
parisc-gcc8
(hppa-linux-gcc (GCC) 8.1.0 / GNU ld (GNU Binutils) 2.30)
Config:
generic-32bit_defconfig
(
download
)
Log:
Download original
Possible warnings (2)
block/genhd.c:1662:1: warning: the frame size of 1720 bytes is larger than 1280 bytes [-Wframe-larger-than=] lib/xxhash.c:236:1: warning: the frame size of 1616 bytes is larger than 1280 bytes [-Wframe-larger-than=]
Full Log
# git rev-parse -q --verify 4df910620bebb5cfe234af16ac8f6474b60215fd^{commit} 4df910620bebb5cfe234af16ac8f6474b60215fd already have revision, skipping fetch # git checkout -q -f -B kisskb 4df910620bebb5cfe234af16ac8f6474b60215fd # git clean -qxdf # < git log -1 # commit 4df910620bebb5cfe234af16ac8f6474b60215fd # Author: Feng Tang <feng.tang@intel.com> # Date: Wed Nov 25 13:22:21 2020 +0800 # # mm: memcg: relayout structure mem_cgroup to avoid cache interference # # 0day reported one -22.7% regression for will-it-scale page_fault2 # case [1] on a 4 sockets 144 CPU platform, and bisected to it to be # caused by Waiman's optimization (commit bd0b230fe1) of saving one # 'struct page_counter' space for 'struct mem_cgroup'. # # Initially we thought it was due to the cache alignment change introduced # by the patch, but further debug shows that it is due to some hot data # members ('vmstats_local', 'vmstats_percpu', 'vmstats') sit in 2 adjacent # cacheline (2N and 2N+1 cacheline), and when adjacent cache line prefetch # is enabled, it triggers an "extended level" of cache false sharing for # 2 adjacent cache lines. # # So exchange the 2 member blocks, while keeping mostly the original # cache alignment, which can restore and even enhance the performance, # and save 64 bytes of space for 'struct mem_cgroup' (from 2880 to 2816, # with 0day's default RHEL-8.3 kernel config) # # [1]. https://lore.kernel.org/lkml/20201102091543.GM31092@shao2-debian/ # # Fixes: bd0b230fe145 ("mm/memcg: unify swap and memsw page counters") # Reported-by: kernel test robot <rong.a.chen@intel.com> # Signed-off-by: Feng Tang <feng.tang@intel.com> # Acked-by: Waiman Long <longman@redhat.com> # Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> # < /opt/cross/kisskb/korg/gcc-8.1.0-nolibc/hppa-linux/bin/hppa-linux-gcc --version # < /opt/cross/kisskb/korg/gcc-8.1.0-nolibc/hppa-linux/bin/hppa-linux-ld --version # < git log --format=%s --max-count=1 4df910620bebb5cfe234af16ac8f6474b60215fd # < make -s -j 120 ARCH=parisc O=/kisskb/build/linus_generic-32bit_defconfig_parisc-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/hppa-linux/bin/hppa-linux- generic-32bit_defconfig # make -s -j 120 ARCH=parisc O=/kisskb/build/linus_generic-32bit_defconfig_parisc-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/hppa-linux/bin/hppa-linux- /kisskb/src/block/genhd.c: In function 'diskstats_show': /kisskb/src/block/genhd.c:1662:1: warning: the frame size of 1720 bytes is larger than 1280 bytes [-Wframe-larger-than=] } ^ /kisskb/src/lib/xxhash.c: In function 'xxh64': /kisskb/src/lib/xxhash.c:236:1: warning: the frame size of 1616 bytes is larger than 1280 bytes [-Wframe-larger-than=] } ^ Completed OK # rm -rf /kisskb/build/linus_generic-32bit_defconfig_parisc-gcc8 # Build took: 0:01:09.875271
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