https://github.com/torvalds/linux
Revision e0c274472d5d27f277af722e017525e0b33784cd authored by Johannes Weiner on 30 November 2018, 22:09:58 UTC, committed by Linus Torvalds on 30 November 2018, 22:56:14 UTC
Mel Gorman reports a hackbench regression with psi that would prohibit shipping the suse kernel with it default-enabled, but he'd still like users to be able to opt in at little to no cost to others. With the current combination of CONFIG_PSI and the psi_disabled bool set from the commandline, this is a challenge. Do the following things to make it easier: 1. Add a config option CONFIG_PSI_DEFAULT_DISABLED that allows distros to enable CONFIG_PSI in their kernel but leave the feature disabled unless a user requests it at boot-time. To avoid double negatives, rename psi_disabled= to psi=. 2. Make psi_disabled a static branch to eliminate any branch costs when the feature is disabled. In terms of numbers before and after this patch, Mel says: : The following is a comparision using CONFIG_PSI=n as a baseline against : your patch and a vanilla kernel : : 4.20.0-rc4 4.20.0-rc4 4.20.0-rc4 : kconfigdisable-v1r1 vanilla psidisable-v1r1 : Amean 1 1.3100 ( 0.00%) 1.3923 ( -6.28%) 1.3427 ( -2.49%) : Amean 3 3.8860 ( 0.00%) 4.1230 * -6.10%* 3.8860 ( -0.00%) : Amean 5 6.8847 ( 0.00%) 8.0390 * -16.77%* 6.7727 ( 1.63%) : Amean 7 9.9310 ( 0.00%) 10.8367 * -9.12%* 9.9910 ( -0.60%) : Amean 12 16.6577 ( 0.00%) 18.2363 * -9.48%* 17.1083 ( -2.71%) : Amean 18 26.5133 ( 0.00%) 27.8833 * -5.17%* 25.7663 ( 2.82%) : Amean 24 34.3003 ( 0.00%) 34.6830 ( -1.12%) 32.0450 ( 6.58%) : Amean 30 40.0063 ( 0.00%) 40.5800 ( -1.43%) 41.5087 ( -3.76%) : Amean 32 40.1407 ( 0.00%) 41.2273 ( -2.71%) 39.9417 ( 0.50%) : : It's showing that the vanilla kernel takes a hit (as the bisection : indicated it would) and that disabling PSI by default is reasonably : close in terms of performance for this particular workload on this : particular machine so; Link: http://lkml.kernel.org/r/20181127165329.GA29728@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Tested-by: Mel Gorman <mgorman@techsingularity.net> Reported-by: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Tip revision: e0c274472d5d27f277af722e017525e0b33784cd authored by Johannes Weiner on 30 November 2018, 22:09:58 UTC
psi: make disabling/enabling easier for vendor kernels
psi: make disabling/enabling easier for vendor kernels
Tip revision: e0c2744
File | Mode | Size |
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9p | ||
adfs | ||
affs | ||
afs | ||
autofs | ||
befs | ||
bfs | ||
btrfs | ||
cachefiles | ||
ceph | ||
cifs | ||
coda | ||
configfs | ||
cramfs | ||
crypto | ||
debugfs | ||
devpts | ||
dlm | ||
ecryptfs | ||
efivarfs | ||
efs | ||
exofs | ||
exportfs | ||
ext2 | ||
ext4 | ||
f2fs | ||
fat | ||
freevxfs | ||
fscache | ||
fuse | ||
gfs2 | ||
hfs | ||
hfsplus | ||
hostfs | ||
hpfs | ||
hugetlbfs | ||
isofs | ||
jbd2 | ||
jffs2 | ||
jfs | ||
kernfs | ||
lockd | ||
minix | ||
nfs | ||
nfs_common | ||
nfsd | ||
nilfs2 | ||
nls | ||
notify | ||
ntfs | ||
ocfs2 | ||
omfs | ||
openpromfs | ||
orangefs | ||
overlayfs | ||
proc | ||
pstore | ||
qnx4 | ||
qnx6 | ||
quota | ||
ramfs | ||
reiserfs | ||
romfs | ||
squashfs | ||
sysfs | ||
sysv | ||
tracefs | ||
ubifs | ||
udf | ||
ufs | ||
xfs | ||
Kconfig | -rw-r--r-- | 7.4 KB |
Kconfig.binfmt | -rw-r--r-- | 7.2 KB |
Makefile | -rw-r--r-- | 4.2 KB |
aio.c | -rw-r--r-- | 54.4 KB |
anon_inodes.c | -rw-r--r-- | 4.5 KB |
attr.c | -rw-r--r-- | 9.7 KB |
bad_inode.c | -rw-r--r-- | 5.3 KB |
binfmt_aout.c | -rw-r--r-- | 10.8 KB |
binfmt_elf.c | -rw-r--r-- | 63.8 KB |
binfmt_elf_fdpic.c | -rw-r--r-- | 47.3 KB |
binfmt_em86.c | -rw-r--r-- | 2.8 KB |
binfmt_flat.c | -rw-r--r-- | 27.7 KB |
binfmt_misc.c | -rw-r--r-- | 18.3 KB |
binfmt_script.c | -rw-r--r-- | 3.0 KB |
block_dev.c | -rw-r--r-- | 53.8 KB |
buffer.c | -rw-r--r-- | 89.9 KB |
char_dev.c | -rw-r--r-- | 16.6 KB |
compat.c | -rw-r--r-- | 3.4 KB |
compat_binfmt_elf.c | -rw-r--r-- | 3.4 KB |
compat_ioctl.c | -rw-r--r-- | 31.0 KB |
coredump.c | -rw-r--r-- | 21.2 KB |
d_path.c | -rw-r--r-- | 11.2 KB |
dax.c | -rw-r--r-- | 45.0 KB |
dcache.c | -rw-r--r-- | 81.2 KB |
dcookies.c | -rw-r--r-- | 7.0 KB |
direct-io.c | -rw-r--r-- | 40.8 KB |
drop_caches.c | -rw-r--r-- | 1.6 KB |
eventfd.c | -rw-r--r-- | 10.8 KB |
eventpoll.c | -rw-r--r-- | 62.8 KB |
exec.c | -rw-r--r-- | 47.0 KB |
fcntl.c | -rw-r--r-- | 23.3 KB |
fhandle.c | -rw-r--r-- | 6.8 KB |
file.c | -rw-r--r-- | 23.4 KB |
file_table.c | -rw-r--r-- | 10.0 KB |
filesystems.c | -rw-r--r-- | 6.2 KB |
fs-writeback.c | -rw-r--r-- | 70.4 KB |
fs_pin.c | -rw-r--r-- | 2.0 KB |
fs_struct.c | -rw-r--r-- | 3.3 KB |
inode.c | -rw-r--r-- | 56.6 KB |
internal.h | -rw-r--r-- | 5.0 KB |
ioctl.c | -rw-r--r-- | 17.7 KB |
iomap.c | -rw-r--r-- | 53.2 KB |
libfs.c | -rw-r--r-- | 31.8 KB |
locks.c | -rw-r--r-- | 73.1 KB |
mbcache.c | -rw-r--r-- | 12.0 KB |
mount.h | -rw-r--r-- | 3.9 KB |
mpage.c | -rw-r--r-- | 21.1 KB |
namei.c | -rw-r--r-- | 123.0 KB |
namespace.c | -rw-r--r-- | 84.6 KB |
no-block.c | -rw-r--r-- | 688 bytes |
nsfs.c | -rw-r--r-- | 6.2 KB |
open.c | -rw-r--r-- | 28.4 KB |
pipe.c | -rw-r--r-- | 26.9 KB |
pnode.c | -rw-r--r-- | 15.3 KB |
pnode.h | -rw-r--r-- | 1.9 KB |
posix_acl.c | -rw-r--r-- | 21.4 KB |
proc_namespace.c | -rw-r--r-- | 7.8 KB |
read_write.c | -rw-r--r-- | 49.6 KB |
readdir.c | -rw-r--r-- | 11.4 KB |
select.c | -rw-r--r-- | 34.6 KB |
seq_file.c | -rw-r--r-- | 24.4 KB |
signalfd.c | -rw-r--r-- | 9.0 KB |
splice.c | -rw-r--r-- | 39.5 KB |
stack.c | -rw-r--r-- | 2.5 KB |
stat.c | -rw-r--r-- | 19.4 KB |
statfs.c | -rw-r--r-- | 9.7 KB |
super.c | -rw-r--r-- | 40.4 KB |
sync.c | -rw-r--r-- | 9.9 KB |
timerfd.c | -rw-r--r-- | 13.4 KB |
userfaultfd.c | -rw-r--r-- | 50.3 KB |
utimes.c | -rw-r--r-- | 7.4 KB |
xattr.c | -rw-r--r-- | 23.4 KB |
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