Buildresult: linus/mips-allnoconfig/mipsel-gcc5 built on Feb 28 2023, 17:13

kisskb

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Status:	OK
Date/Time:	Feb 28 2023, 17:13
Duration:	0:00:44.648229
Builder:	blade4b
Revision:	vfs: avoid duplicating creds in faccessat if possible (`981ee95cc1f5905ae4936b0dd501085909cdc14f)`
Target:	linus/mips-allnoconfig/mipsel-gcc5
Branch:	linus
Compiler:	mipsel-gcc5 (mipsel-linux-gcc.br_real (Buildroot 2016.11-git-00613-ge98b4dd) 5.4.0 / GNU ld (GNU Binutils) 2.26.1)
Config:	allnoconfig (download)
Log:	Download original No warnings found in log. Full Log # git rev-parse -q --verify 981ee95cc1f5905ae4936b0dd501085909cdc14f^{commit} 981ee95cc1f5905ae4936b0dd501085909cdc14f already have revision, skipping fetch # git checkout -q -f -B kisskb 981ee95cc1f5905ae4936b0dd501085909cdc14f # git clean -qxdf # < git log -1 # commit 981ee95cc1f5905ae4936b0dd501085909cdc14f # Author: Mateusz Guzik <mjguzik@gmail.com> # Date: Wed Jan 25 16:55:57 2023 +0100 # # vfs: avoid duplicating creds in faccessat if possible # # access(2) remains commonly used, for example on exec: # access("/etc/ld.so.preload", R_OK) # # or when running gcc: strace -c gcc empty.c # # % time seconds usecs/call calls errors syscall # ------ ----------- ----------- --------- --------- ---------------- # 0.00 0.000000 0 42 26 access # # It falls down to do_faccessat without the AT_EACCESS flag, which in turn # results in allocation of new creds in order to modify fsuid/fsgid and # caps. This is a very expensive process single-threaded and most notably # multi-threaded, with numerous structures getting refed and unrefed on # imminent new cred destruction. # # Turns out for typical consumers the resulting creds would be identical # and this can be checked upfront, avoiding the hard work. # # An access benchmark plugged into will-it-scale running on Cascade Lake # shows: # # test proc before after # access1 1 1310582 2908735 (+121%) # distinct files # access1 24 4716491 63822173 (+1353%) # distinct files # access2 24 2378041 5370335 (+125%) # same file # # The above benchmarks are not integrated into will-it-scale, but can be # found in a pull request: # # https://github.com/antonblanchard/will-it-scale/pull/36/files # # Signed-off-by: Mateusz Guzik <mjguzik@gmail.com> # Cc: Al Viro <viro@zeniv.linux.org.uk> # Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> # < /opt/cross/kisskb/br-mipsel-o32-full-2016.08-613-ge98b4dd/bin/mipsel-linux-gcc --version # < /opt/cross/kisskb/br-mipsel-o32-full-2016.08-613-ge98b4dd/bin/mipsel-linux-ld --version # < git log --format=%s --max-count=1 981ee95cc1f5905ae4936b0dd501085909cdc14f # < make -s -j 24 ARCH=mips O=/kisskb/build/linus_mips-allnoconfig_mipsel-gcc5 CROSS_COMPILE=/opt/cross/kisskb/br-mipsel-o32-full-2016.08-613-ge98b4dd/bin/mipsel-linux- allnoconfig # < make -s -j 24 ARCH=mips O=/kisskb/build/linus_mips-allnoconfig_mipsel-gcc5 CROSS_COMPILE=/opt/cross/kisskb/br-mipsel-o32-full-2016.08-613-ge98b4dd/bin/mipsel-linux- help # make -s -j 24 ARCH=mips O=/kisskb/build/linus_mips-allnoconfig_mipsel-gcc5 CROSS_COMPILE=/opt/cross/kisskb/br-mipsel-o32-full-2016.08-613-ge98b4dd/bin/mipsel-linux- olddefconfig # make -s -j 24 ARCH=mips O=/kisskb/build/linus_mips-allnoconfig_mipsel-gcc5 CROSS_COMPILE=/opt/cross/kisskb/br-mipsel-o32-full-2016.08-613-ge98b4dd/bin/mipsel-linux- Completed OK # rm -rf /kisskb/build/linus_mips-allnoconfig_mipsel-gcc5 # Build took: 0:00:44.648229

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