Buildresult: linus/arm64-defconfig/arm64-gcc5 built on Feb 28 2023, 16:09

kisskb

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Status:	OK
Date/Time:	Feb 28 2023, 16:09
Duration:	0:03:56.887488
Builder:	ka4
Revision:	vfs: avoid duplicating creds in faccessat if possible (`981ee95cc1f5905ae4936b0dd501085909cdc14f)`
Target:	linus/arm64-defconfig/arm64-gcc5
Branch:	linus
Compiler:	arm64-gcc5 (aarch64-linux-gcc (GCC) 5.5.0 / GNU ld (GNU Binutils) 2.29.1.20170915)
Config:	defconfig (download)
Log:	Download original Possible warnings (2) fs/btrfs/send.c:1909:13: warning: 'right_gen' may be used uninitialized in this function [-Wmaybe-uninitialized] cc1: warning: unrecognized command line option '-Wno-shift-negative-value' 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/korg/gcc-5.5.0-nolibc/aarch64-linux/bin/aarch64-linux-gcc --version # < /opt/cross/kisskb/korg/gcc-5.5.0-nolibc/aarch64-linux/bin/aarch64-linux-ld --version # < git log --format=%s --max-count=1 981ee95cc1f5905ae4936b0dd501085909cdc14f # < make -s -j 40 ARCH=arm64 O=/kisskb/build/linus_arm64-defconfig_arm64-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/aarch64-linux/bin/aarch64-linux- defconfig # < make -s -j 40 ARCH=arm64 O=/kisskb/build/linus_arm64-defconfig_arm64-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/aarch64-linux/bin/aarch64-linux- help # make -s -j 40 ARCH=arm64 O=/kisskb/build/linus_arm64-defconfig_arm64-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/aarch64-linux/bin/aarch64-linux- olddefconfig # make -s -j 40 ARCH=arm64 O=/kisskb/build/linus_arm64-defconfig_arm64-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/aarch64-linux/bin/aarch64-linux- /kisskb/src/fs/btrfs/send.c: In function 'get_cur_inode_state': /kisskb/src/fs/btrfs/send.c:1909:13: warning: 'right_gen' may be used uninitialized in this function [-Wmaybe-uninitialized] } else if (right_gen == gen) { ^ /kisskb/src/fs/btrfs/send.c: At top level: cc1: warning: unrecognized command line option '-Wno-shift-negative-value' Completed OK # rm -rf /kisskb/build/linus_arm64-defconfig_arm64-gcc5 # Build took: 0:03:56.887488

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