[PATCH 1/2] blk-cgroup: refactor blkcg_print_stat
From: Christoph Hellwig <hch@lst.de>
Date: 2021-08-10 15:27:55
Factor out a helper to deal with a single blkcg_gq to make the code a little bit easier to follow. Signed-off-by: Christoph Hellwig <hch@lst.de> --- block/blk-cgroup.c | 148 ++++++++++++++++++++++----------------------- 1 file changed, 74 insertions(+), 74 deletions(-)
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index db034e35ae20..52aa0540ccaf 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c@@ -870,97 +870,97 @@ static void blkcg_fill_root_iostats(void) } } -static int blkcg_print_stat(struct seq_file *sf, void *v) +static void blkcg_print_one_stat(struct blkcg_gq *blkg, struct seq_file *s) { - struct blkcg *blkcg = css_to_blkcg(seq_css(sf)); - struct blkcg_gq *blkg; - - if (!seq_css(sf)->parent) - blkcg_fill_root_iostats(); - else - cgroup_rstat_flush(blkcg->css.cgroup); - - rcu_read_lock(); + struct blkg_iostat_set *bis = &blkg->iostat; + u64 rbytes, wbytes, rios, wios, dbytes, dios; + bool has_stats = false; + const char *dname; + unsigned seq; + char *buf; + size_t size = seq_get_buf(s, &buf), off = 0; + int i; - hlist_for_each_entry_rcu(blkg, &blkcg->blkg_list, blkcg_node) { - struct blkg_iostat_set *bis = &blkg->iostat; - const char *dname; - char *buf; - u64 rbytes, wbytes, rios, wios, dbytes, dios; - size_t size = seq_get_buf(sf, &buf), off = 0; - int i; - bool has_stats = false; - unsigned seq; + if (!blkg->online) + return; - spin_lock_irq(&blkg->q->queue_lock); + dname = blkg_dev_name(blkg); + if (!dname) + return; - if (!blkg->online) - goto skip; + /* + * Hooray string manipulation, count is the size written NOT + * INCLUDING THE \0, so size is now count+1 less than what we + * had before, but we want to start writing the next bit from + * the \0 so we only add count to buf. + */ + off += scnprintf(buf+off, size-off, "%s ", dname); - dname = blkg_dev_name(blkg); - if (!dname) - goto skip; + do { + seq = u64_stats_fetch_begin(&bis->sync); + + rbytes = bis->cur.bytes[BLKG_IOSTAT_READ]; + wbytes = bis->cur.bytes[BLKG_IOSTAT_WRITE]; + dbytes = bis->cur.bytes[BLKG_IOSTAT_DISCARD]; + rios = bis->cur.ios[BLKG_IOSTAT_READ]; + wios = bis->cur.ios[BLKG_IOSTAT_WRITE]; + dios = bis->cur.ios[BLKG_IOSTAT_DISCARD]; + } while (u64_stats_fetch_retry(&bis->sync, seq)); + + if (rbytes || wbytes || rios || wios) { + has_stats = true; + off += scnprintf(buf+off, size-off, + "rbytes=%llu wbytes=%llu rios=%llu wios=%llu dbytes=%llu dios=%llu", + rbytes, wbytes, rios, wios, + dbytes, dios); + } - /* - * Hooray string manipulation, count is the size written NOT - * INCLUDING THE \0, so size is now count+1 less than what we - * had before, but we want to start writing the next bit from - * the \0 so we only add count to buf. - */ - off += scnprintf(buf+off, size-off, "%s ", dname); + if (blkcg_debug_stats && atomic_read(&blkg->use_delay)) { + has_stats = true; + off += scnprintf(buf+off, size-off, " use_delay=%d delay_nsec=%llu", + atomic_read(&blkg->use_delay), + atomic64_read(&blkg->delay_nsec)); + } - do { - seq = u64_stats_fetch_begin(&bis->sync); + for (i = 0; i < BLKCG_MAX_POLS; i++) { + struct blkcg_policy *pol = blkcg_policy[i]; + size_t written; - rbytes = bis->cur.bytes[BLKG_IOSTAT_READ]; - wbytes = bis->cur.bytes[BLKG_IOSTAT_WRITE]; - dbytes = bis->cur.bytes[BLKG_IOSTAT_DISCARD]; - rios = bis->cur.ios[BLKG_IOSTAT_READ]; - wios = bis->cur.ios[BLKG_IOSTAT_WRITE]; - dios = bis->cur.ios[BLKG_IOSTAT_DISCARD]; - } while (u64_stats_fetch_retry(&bis->sync, seq)); + if (!blkg->pd[i] || !pol->pd_stat_fn) + continue; - if (rbytes || wbytes || rios || wios) { + written = pol->pd_stat_fn(blkg->pd[i], buf+off, size-off); + if (written) has_stats = true; - off += scnprintf(buf+off, size-off, - "rbytes=%llu wbytes=%llu rios=%llu wios=%llu dbytes=%llu dios=%llu", - rbytes, wbytes, rios, wios, - dbytes, dios); - } + off += written; + } - if (blkcg_debug_stats && atomic_read(&blkg->use_delay)) { - has_stats = true; - off += scnprintf(buf+off, size-off, - " use_delay=%d delay_nsec=%llu", - atomic_read(&blkg->use_delay), - (unsigned long long)atomic64_read(&blkg->delay_nsec)); + if (has_stats) { + if (off < size - 1) { + off += scnprintf(buf+off, size-off, "\n"); + seq_commit(s, off); + } else { + seq_commit(s, -1); } + } +} - for (i = 0; i < BLKCG_MAX_POLS; i++) { - struct blkcg_policy *pol = blkcg_policy[i]; - size_t written; - - if (!blkg->pd[i] || !pol->pd_stat_fn) - continue; +static int blkcg_print_stat(struct seq_file *sf, void *v) +{ + struct blkcg *blkcg = css_to_blkcg(seq_css(sf)); + struct blkcg_gq *blkg; - written = pol->pd_stat_fn(blkg->pd[i], buf+off, size-off); - if (written) - has_stats = true; - off += written; - } + if (!seq_css(sf)->parent) + blkcg_fill_root_iostats(); + else + cgroup_rstat_flush(blkcg->css.cgroup); - if (has_stats) { - if (off < size - 1) { - off += scnprintf(buf+off, size-off, "\n"); - seq_commit(sf, off); - } else { - seq_commit(sf, -1); - } - } - skip: + rcu_read_lock(); + hlist_for_each_entry_rcu(blkg, &blkcg->blkg_list, blkcg_node) { + spin_lock_irq(&blkg->q->queue_lock); + blkcg_print_one_stat(blkg, sf); spin_unlock_irq(&blkg->q->queue_lock); } - rcu_read_unlock(); return 0; }
--
2.30.2