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blk-cgroup: factor out blkcg_iostat_update()
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To reduce some duplicated code, factor out blkcg_iostat_update(). No
functional change.

Signed-off-by: Jason Yan <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>
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JasonYanHw authored and axboe committed Jun 29, 2022
1 parent 22d0c40 commit 362b8c1
Showing 1 changed file with 20 additions and 17 deletions.
37 changes: 20 additions & 17 deletions block/blk-cgroup.c
Original file line number Diff line number Diff line change
Expand Up @@ -846,6 +846,21 @@ static void blkg_iostat_sub(struct blkg_iostat *dst, struct blkg_iostat *src)
}
}

static void blkcg_iostat_update(struct blkcg_gq *blkg, struct blkg_iostat *cur,
struct blkg_iostat *last)
{
struct blkg_iostat delta;
unsigned long flags;

/* propagate percpu delta to global */
flags = u64_stats_update_begin_irqsave(&blkg->iostat.sync);
blkg_iostat_set(&delta, cur);
blkg_iostat_sub(&delta, last);
blkg_iostat_add(&blkg->iostat.cur, &delta);
blkg_iostat_add(last, &delta);
u64_stats_update_end_irqrestore(&blkg->iostat.sync, flags);
}

static void blkcg_rstat_flush(struct cgroup_subsys_state *css, int cpu)
{
struct blkcg *blkcg = css_to_blkcg(css);
Expand All @@ -860,8 +875,7 @@ static void blkcg_rstat_flush(struct cgroup_subsys_state *css, int cpu)
hlist_for_each_entry_rcu(blkg, &blkcg->blkg_list, blkcg_node) {
struct blkcg_gq *parent = blkg->parent;
struct blkg_iostat_set *bisc = per_cpu_ptr(blkg->iostat_cpu, cpu);
struct blkg_iostat cur, delta;
unsigned long flags;
struct blkg_iostat cur;
unsigned int seq;

/* fetch the current per-cpu values */
Expand All @@ -870,23 +884,12 @@ static void blkcg_rstat_flush(struct cgroup_subsys_state *css, int cpu)
blkg_iostat_set(&cur, &bisc->cur);
} while (u64_stats_fetch_retry(&bisc->sync, seq));

/* propagate percpu delta to global */
flags = u64_stats_update_begin_irqsave(&blkg->iostat.sync);
blkg_iostat_set(&delta, &cur);
blkg_iostat_sub(&delta, &bisc->last);
blkg_iostat_add(&blkg->iostat.cur, &delta);
blkg_iostat_add(&bisc->last, &delta);
u64_stats_update_end_irqrestore(&blkg->iostat.sync, flags);
blkcg_iostat_update(blkg, &cur, &bisc->last);

/* propagate global delta to parent (unless that's root) */
if (parent && parent->parent) {
flags = u64_stats_update_begin_irqsave(&parent->iostat.sync);
blkg_iostat_set(&delta, &blkg->iostat.cur);
blkg_iostat_sub(&delta, &blkg->iostat.last);
blkg_iostat_add(&parent->iostat.cur, &delta);
blkg_iostat_add(&blkg->iostat.last, &delta);
u64_stats_update_end_irqrestore(&parent->iostat.sync, flags);
}
if (parent && parent->parent)
blkcg_iostat_update(parent, &blkg->iostat.cur,
&blkg->iostat.last);
}

rcu_read_unlock();
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