Revision 2bbd00aef0671bfe3c2ca5ba67097246257de125 authored by Johannes Weiner on 26 February 2021, 01:16:47 UTC, committed by Linus Torvalds on 26 February 2021, 17:41:00 UTC
On NOHZ, the periodic vmstat flushers on each CPU can go to sleep and
won't wake up until stat changes are detected in the per-cpu deltas of the
zone vmstat counters.
In commit 75ef71840539 ("mm, vmstat: add infrastructure for per-node
vmstats") per-node counters were introduced, and subsequently most stats
were moved from the zone to the node level. However, the node counters
weren't added to the NOHZ wakeup detection.
In theory this can cause per-cpu errors to remain in the user-reported
stats indefinitely. In practice this only affects a handful of sub
counters (file_mapped, dirty and writeback e.g.) because other page state
changes at the node level likely involve a change at the zone level as
well (alloc and free, lru ops). Also, nobody has complained.
Fix it up for completeness: wake up vmstat refreshing on node changes.
Also remove the BUILD_BUG_ONs that assert counter size; we haven't relied
on it since we added sizeof() to the range calculation in commit
13c9aaf7fa01 ("mm/vmstat.c: fix NUMA statistics updates").
Link: https://lkml.kernel.org/r/20210202184342.118513-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent a052d4d
raid5-log.h
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _RAID5_LOG_H
#define _RAID5_LOG_H
extern int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev);
extern void r5l_exit_log(struct r5conf *conf);
extern int r5l_write_stripe(struct r5l_log *log, struct stripe_head *head_sh);
extern void r5l_write_stripe_run(struct r5l_log *log);
extern void r5l_flush_stripe_to_raid(struct r5l_log *log);
extern void r5l_stripe_write_finished(struct stripe_head *sh);
extern int r5l_handle_flush_request(struct r5l_log *log, struct bio *bio);
extern void r5l_quiesce(struct r5l_log *log, int quiesce);
extern bool r5l_log_disk_error(struct r5conf *conf);
extern bool r5c_is_writeback(struct r5l_log *log);
extern int
r5c_try_caching_write(struct r5conf *conf, struct stripe_head *sh,
struct stripe_head_state *s, int disks);
extern void
r5c_finish_stripe_write_out(struct r5conf *conf, struct stripe_head *sh,
struct stripe_head_state *s);
extern void r5c_release_extra_page(struct stripe_head *sh);
extern void r5c_use_extra_page(struct stripe_head *sh);
extern void r5l_wake_reclaim(struct r5l_log *log, sector_t space);
extern void r5c_handle_cached_data_endio(struct r5conf *conf,
struct stripe_head *sh, int disks);
extern int r5c_cache_data(struct r5l_log *log, struct stripe_head *sh);
extern void r5c_make_stripe_write_out(struct stripe_head *sh);
extern void r5c_flush_cache(struct r5conf *conf, int num);
extern void r5c_check_stripe_cache_usage(struct r5conf *conf);
extern void r5c_check_cached_full_stripe(struct r5conf *conf);
extern struct md_sysfs_entry r5c_journal_mode;
extern void r5c_update_on_rdev_error(struct mddev *mddev,
struct md_rdev *rdev);
extern bool r5c_big_stripe_cached(struct r5conf *conf, sector_t sect);
extern int r5l_start(struct r5l_log *log);
extern struct dma_async_tx_descriptor *
ops_run_partial_parity(struct stripe_head *sh, struct raid5_percpu *percpu,
struct dma_async_tx_descriptor *tx);
extern int ppl_init_log(struct r5conf *conf);
extern void ppl_exit_log(struct r5conf *conf);
extern int ppl_write_stripe(struct r5conf *conf, struct stripe_head *sh);
extern void ppl_write_stripe_run(struct r5conf *conf);
extern void ppl_stripe_write_finished(struct stripe_head *sh);
extern int ppl_modify_log(struct r5conf *conf, struct md_rdev *rdev, bool add);
extern void ppl_quiesce(struct r5conf *conf, int quiesce);
extern int ppl_handle_flush_request(struct r5l_log *log, struct bio *bio);
extern struct md_sysfs_entry ppl_write_hint;
static inline bool raid5_has_log(struct r5conf *conf)
{
return test_bit(MD_HAS_JOURNAL, &conf->mddev->flags);
}
static inline bool raid5_has_ppl(struct r5conf *conf)
{
return test_bit(MD_HAS_PPL, &conf->mddev->flags);
}
static inline int log_stripe(struct stripe_head *sh, struct stripe_head_state *s)
{
struct r5conf *conf = sh->raid_conf;
if (conf->log) {
if (!test_bit(STRIPE_R5C_CACHING, &sh->state)) {
/* writing out phase */
if (s->waiting_extra_page)
return 0;
return r5l_write_stripe(conf->log, sh);
} else if (test_bit(STRIPE_LOG_TRAPPED, &sh->state)) {
/* caching phase */
return r5c_cache_data(conf->log, sh);
}
} else if (raid5_has_ppl(conf)) {
return ppl_write_stripe(conf, sh);
}
return -EAGAIN;
}
static inline void log_stripe_write_finished(struct stripe_head *sh)
{
struct r5conf *conf = sh->raid_conf;
if (conf->log)
r5l_stripe_write_finished(sh);
else if (raid5_has_ppl(conf))
ppl_stripe_write_finished(sh);
}
static inline void log_write_stripe_run(struct r5conf *conf)
{
if (conf->log)
r5l_write_stripe_run(conf->log);
else if (raid5_has_ppl(conf))
ppl_write_stripe_run(conf);
}
static inline void log_flush_stripe_to_raid(struct r5conf *conf)
{
if (conf->log)
r5l_flush_stripe_to_raid(conf->log);
else if (raid5_has_ppl(conf))
ppl_write_stripe_run(conf);
}
static inline int log_handle_flush_request(struct r5conf *conf, struct bio *bio)
{
int ret = -ENODEV;
if (conf->log)
ret = r5l_handle_flush_request(conf->log, bio);
else if (raid5_has_ppl(conf))
ret = ppl_handle_flush_request(conf->log, bio);
return ret;
}
static inline void log_quiesce(struct r5conf *conf, int quiesce)
{
if (conf->log)
r5l_quiesce(conf->log, quiesce);
else if (raid5_has_ppl(conf))
ppl_quiesce(conf, quiesce);
}
static inline void log_exit(struct r5conf *conf)
{
if (conf->log)
r5l_exit_log(conf);
else if (raid5_has_ppl(conf))
ppl_exit_log(conf);
}
static inline int log_init(struct r5conf *conf, struct md_rdev *journal_dev,
bool ppl)
{
if (journal_dev)
return r5l_init_log(conf, journal_dev);
else if (ppl)
return ppl_init_log(conf);
return 0;
}
static inline int log_modify(struct r5conf *conf, struct md_rdev *rdev, bool add)
{
if (raid5_has_ppl(conf))
return ppl_modify_log(conf, rdev, add);
return 0;
}
#endif
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