From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Josef Bacik To: axboe@kernel.dk, kernel-team@fb.com, linux-block@vger.kernel.org, akpm@linux-foundation.org, linux-mm@kvack.org, hannes@cmpxchg.org, linux-kernel@vger.kernel.org, tj@kernel.org, linux-fsdevel@vger.kernel.org Cc: Josef Bacik Subject: [PATCH 03/13] blk-cgroup: allow controllers to output their own stats Date: Tue, 29 May 2018 17:17:14 -0400 Message-Id: <20180529211724.4531-4-josef@toxicpanda.com> In-Reply-To: <20180529211724.4531-1-josef@toxicpanda.com> References: <20180529211724.4531-1-josef@toxicpanda.com> Sender: owner-linux-mm@kvack.org List-ID: From: Josef Bacik blk-iolatency has a few stats that it would like to print out, and instead of adding a bunch of crap to the generic code just provide a helper so that controllers can add stuff to the stat line if they want to. Signed-off-by: Josef Bacik --- block/blk-cgroup.c | 52 +++++++++++++++++++++++++++++++++++++++++++--- include/linux/blk-cgroup.h | 3 +++ 2 files changed, 52 insertions(+), 3 deletions(-) diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index eb85cb87c40f..9e767e4a852d 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -954,13 +954,28 @@ static int blkcg_print_stat(struct seq_file *sf, void *v) hlist_for_each_entry_rcu(blkg, &blkcg->blkg_list, blkcg_node) { const char *dname; + char *buf; struct blkg_rwstat rwstat; u64 rbytes, wbytes, rios, wios; + size_t size = seq_get_buf(sf, &buf), count = 0, total = 0; + int i; dname = blkg_dev_name(blkg); if (!dname) continue; + /* + * 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. + */ + count = snprintf(buf, size, "%s ", dname); + if (count >= size) + continue; + buf += count; + size -= count + 1; + spin_lock_irq(blkg->q->queue_lock); rwstat = blkg_rwstat_recursive_sum(blkg, NULL, @@ -975,9 +990,40 @@ static int blkcg_print_stat(struct seq_file *sf, void *v) spin_unlock_irq(blkg->q->queue_lock); - if (rbytes || wbytes || rios || wios) - seq_printf(sf, "%s rbytes=%llu wbytes=%llu rios=%llu wios=%llu\n", - dname, rbytes, wbytes, rios, wios); + if (rbytes || wbytes || rios || wios) { + total += count; + count = snprintf(buf, size, + "rbytes=%llu wbytes=%llu rios=%llu wios=%llu", + rbytes, wbytes, rios, wios); + if (count >= size) + continue; + buf += count; + total += count; + size -= count + 1; + } + + mutex_lock(&blkcg_pol_mutex); + for (i = 0; i < BLKCG_MAX_POLS; i++) { + struct blkcg_policy *pol = blkcg_policy[i]; + + if (!blkg->pd[i] || !pol->pd_stat_fn) + continue; + + count = pol->pd_stat_fn(blkg->pd[i], buf, size); + if (count >= size) + continue; + buf += count; + total += count; + size -= count + 1; + } + mutex_unlock(&blkcg_pol_mutex); + if (total) { + count = snprintf(buf, size, "\n"); + if (count >= size) + continue; + total += count; + seq_commit(sf, total); + } } rcu_read_unlock(); diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h index 69aa71dc0c04..b41292726c0f 100644 --- a/include/linux/blk-cgroup.h +++ b/include/linux/blk-cgroup.h @@ -148,6 +148,8 @@ typedef void (blkcg_pol_online_pd_fn)(struct blkg_policy_data *pd); typedef void (blkcg_pol_offline_pd_fn)(struct blkg_policy_data *pd); typedef void (blkcg_pol_free_pd_fn)(struct blkg_policy_data *pd); typedef void (blkcg_pol_reset_pd_stats_fn)(struct blkg_policy_data *pd); +typedef size_t (blkcg_pol_stat_pd_fn)(struct blkg_policy_data *pd, char *buf, + size_t size); struct blkcg_policy { int plid; @@ -167,6 +169,7 @@ struct blkcg_policy { blkcg_pol_offline_pd_fn *pd_offline_fn; blkcg_pol_free_pd_fn *pd_free_fn; blkcg_pol_reset_pd_stats_fn *pd_reset_stats_fn; + blkcg_pol_stat_pd_fn *pd_stat_fn; }; extern struct blkcg blkcg_root; -- 2.14.3