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| author | ZhengYuan Liu <liuzhengyuan@kylinos.cn> | 2016-07-28 08:22:14 +0200 |
|---|---|---|
| committer | Shaohua Li <shli@fb.com> | 2016-08-02 05:18:21 +0200 |
| commit | ff00d3b4e5e4395c825e8ec628f25932d812f31a (patch) | |
| tree | b533f4994a7e780a5f3433869ea5da3f6fedf55b /drivers/md | |
| parent | raid10: increment write counter after bio is split (diff) | |
| download | linux-ff00d3b4e5e4395c825e8ec628f25932d812f31a.tar.xz linux-ff00d3b4e5e4395c825e8ec628f25932d812f31a.zip | |
raid5: fix incorrectly counter of conf->empty_inactive_list_nr
The counter conf->empty_inactive_list_nr is only used for determine if the
raid5 is congested which is deal with in function raid5_congested().
It was increased in get_free_stripe() when conf->inactive_list got to be
empty and decreased in release_inactive_stripe_list() when splice
temp_inactive_list to conf->inactive_list. However, this may have a
problem when raid5_get_active_stripe or stripe_add_to_batch_list was called,
because these two functions may call list_del_init(&sh->lru) to delete sh from
"conf->inactive_list + hash" which may cause "conf->inactive_list + hash" to
be empty when atomic_inc_not_zero(&sh->count) got false. So a check should be
done at these two point and increase empty_inactive_list_nr accordingly.
Otherwise the counter may get to be negative number which would influence
async readahead from VFS.
Signed-off-by: ZhengYuan Liu <liuzhengyuan@kylinos.cn>
Signed-off-by: Shaohua Li <shli@fb.com>
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/raid5.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index d189e894b921..e379b89fd8b1 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -659,6 +659,7 @@ raid5_get_active_stripe(struct r5conf *conf, sector_t sector, { struct stripe_head *sh; int hash = stripe_hash_locks_hash(sector); + int inc_empty_inactive_list_flag; pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector); @@ -703,7 +704,12 @@ raid5_get_active_stripe(struct r5conf *conf, sector_t sector, atomic_inc(&conf->active_stripes); BUG_ON(list_empty(&sh->lru) && !test_bit(STRIPE_EXPANDING, &sh->state)); + inc_empty_inactive_list_flag = 0; + if (!list_empty(conf->inactive_list + hash)) + inc_empty_inactive_list_flag = 1; list_del_init(&sh->lru); + if (list_empty(conf->inactive_list + hash) && inc_empty_inactive_list_flag) + atomic_inc(&conf->empty_inactive_list_nr); if (sh->group) { sh->group->stripes_cnt--; sh->group = NULL; @@ -762,6 +768,7 @@ static void stripe_add_to_batch_list(struct r5conf *conf, struct stripe_head *sh sector_t head_sector, tmp_sec; int hash; int dd_idx; + int inc_empty_inactive_list_flag; /* Don't cross chunks, so stripe pd_idx/qd_idx is the same */ tmp_sec = sh->sector; @@ -779,7 +786,12 @@ static void stripe_add_to_batch_list(struct r5conf *conf, struct stripe_head *sh atomic_inc(&conf->active_stripes); BUG_ON(list_empty(&head->lru) && !test_bit(STRIPE_EXPANDING, &head->state)); + inc_empty_inactive_list_flag = 0; + if (!list_empty(conf->inactive_list + hash)) + inc_empty_inactive_list_flag = 1; list_del_init(&head->lru); + if (list_empty(conf->inactive_list + hash) && inc_empty_inactive_list_flag) + atomic_inc(&conf->empty_inactive_list_nr); if (head->group) { head->group->stripes_cnt--; head->group = NULL; |