forked from Minki/linux
997a026c80
blkiocg_reset_stats() implements stat reset for blkio.reset_stats cgroupfs file. This feature is very unconventional and something which shouldn't have been merged. It's only useful when there's only one user or tool looking at the stats. As soon as multiple users and/or tools are involved, it becomes useless as resetting disrupts other usages. There are very good reasons why all other stats expect readers to read values at the start and end of a period and subtract to determine delta over the period. The implementation is rather complex - some fields shouldn't be cleared and it saves some fields, resets whole and restores for some reason. Reset of percpu stats is also racy. The comment points to 64bit store atomicity for the reason but even without that stores for zero can simply race with other CPUs doing RMW and get clobbered. Simplify reset by * Clear selectively instead of resetting and restoring. * Grouping debug stat fields to be reset and using memset() over them. * Not caring about stats_lock. * Using memset() to reset percpu stats. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> |
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| .. | ||
| partitions | ||
| blk-cgroup.c | ||
| blk-cgroup.h | ||
| blk-core.c | ||
| blk-exec.c | ||
| blk-flush.c | ||
| blk-integrity.c | ||
| blk-ioc.c | ||
| blk-iopoll.c | ||
| blk-lib.c | ||
| blk-map.c | ||
| blk-merge.c | ||
| blk-settings.c | ||
| blk-softirq.c | ||
| blk-sysfs.c | ||
| blk-tag.c | ||
| blk-throttle.c | ||
| blk-timeout.c | ||
| blk.h | ||
| bsg-lib.c | ||
| bsg.c | ||
| cfq-iosched.c | ||
| cfq.h | ||
| compat_ioctl.c | ||
| deadline-iosched.c | ||
| elevator.c | ||
| genhd.c | ||
| ioctl.c | ||
| Kconfig | ||
| Kconfig.iosched | ||
| Makefile | ||
| noop-iosched.c | ||
| partition-generic.c | ||
| scsi_ioctl.c | ||