Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965661AbcKNW0B (ORCPT ); Mon, 14 Nov 2016 17:26:01 -0500 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:55975 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965047AbcKNWWZ (ORCPT ); Mon, 14 Nov 2016 17:22:25 -0500 From: Shaohua Li To: , CC: , , , Subject: [PATCH V4 07/15] blk-throttle: make throtl_slice tunable Date: Mon, 14 Nov 2016 14:22:14 -0800 Message-ID: <24137f881a149d30b98ef040367f26378128d4d2.1479161136.git.shli@fb.com> X-Mailer: git-send-email 2.9.3 In-Reply-To: References: X-FB-Internal: Safe MIME-Version: 1.0 Content-Type: text/plain X-Proofpoint-Spam-Reason: safe X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-11-14_13:,, signatures=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 9648 Lines: 269 throtl_slice is important for blk-throttling. A lot of stuffes depend on it, for example, throughput measurement. It has 100ms default value, which is not appropriate for all disks. For example, for SSD we might use a smaller value to make the throughput smoother. This patch makes it tunable. Signed-off-by: Shaohua Li --- block/blk-sysfs.c | 11 ++++++++ block/blk-throttle.c | 77 +++++++++++++++++++++++++++++++++++++--------------- block/blk.h | 3 ++ 3 files changed, 69 insertions(+), 22 deletions(-) diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 9cc8d7c..3e284e4 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -526,6 +526,14 @@ static struct queue_sysfs_entry queue_dax_entry = { .show = queue_dax_show, }; +#ifdef CONFIG_BLK_DEV_THROTTLING +static struct queue_sysfs_entry throtl_slice_entry = { + .attr = {.name = "throttling_slice", .mode = S_IRUGO | S_IWUSR }, + .show = blk_throtl_slice_show, + .store = blk_throtl_slice_store, +}; +#endif + static struct attribute *default_attrs[] = { &queue_requests_entry.attr, &queue_ra_entry.attr, @@ -553,6 +561,9 @@ static struct attribute *default_attrs[] = { &queue_poll_entry.attr, &queue_wc_entry.attr, &queue_dax_entry.attr, +#ifdef CONFIG_BLK_DEV_THROTTLING + &throtl_slice_entry.attr, +#endif NULL, }; diff --git a/block/blk-throttle.c b/block/blk-throttle.c index eff3120..e85b2b6 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -19,7 +19,8 @@ static int throtl_grp_quantum = 8; static int throtl_quantum = 32; /* Throttling is performed over 100ms slice and after that slice is renewed */ -static unsigned long throtl_slice = HZ/10; /* 100 ms */ +#define DFL_THROTL_SLICE (HZ / 10) +#define MAX_THROTL_SLICE (HZ / 5) static struct blkcg_policy blkcg_policy_throtl; @@ -158,6 +159,8 @@ struct throtl_data /* Total Number of queued bios on READ and WRITE lists */ unsigned int nr_queued[2]; + unsigned int throtl_slice; + /* Work for dispatching throttled bios */ struct work_struct dispatch_work; unsigned int limit_index; @@ -589,7 +592,7 @@ static void throtl_dequeue_tg(struct throtl_grp *tg) static void throtl_schedule_pending_timer(struct throtl_service_queue *sq, unsigned long expires) { - unsigned long max_expire = jiffies + 8 * throtl_slice; + unsigned long max_expire = jiffies + 8 * sq_to_tg(sq)->td->throtl_slice; if (time_after(expires, max_expire)) expires = max_expire; @@ -650,7 +653,7 @@ static inline void throtl_start_new_slice_with_credit(struct throtl_grp *tg, if (time_after_eq(start, tg->slice_start[rw])) tg->slice_start[rw] = start; - tg->slice_end[rw] = jiffies + throtl_slice; + tg->slice_end[rw] = jiffies + tg->td->throtl_slice; throtl_log(&tg->service_queue, "[%c] new slice with credit start=%lu end=%lu jiffies=%lu", rw == READ ? 'R' : 'W', tg->slice_start[rw], @@ -662,7 +665,7 @@ static inline void throtl_start_new_slice(struct throtl_grp *tg, bool rw) tg->bytes_disp[rw] = 0; tg->io_disp[rw] = 0; tg->slice_start[rw] = jiffies; - tg->slice_end[rw] = jiffies + throtl_slice; + tg->slice_end[rw] = jiffies + tg->td->throtl_slice; throtl_log(&tg->service_queue, "[%c] new slice start=%lu end=%lu jiffies=%lu", rw == READ ? 'R' : 'W', tg->slice_start[rw], @@ -672,13 +675,13 @@ static inline void throtl_start_new_slice(struct throtl_grp *tg, bool rw) static inline void throtl_set_slice_end(struct throtl_grp *tg, bool rw, unsigned long jiffy_end) { - tg->slice_end[rw] = roundup(jiffy_end, throtl_slice); + tg->slice_end[rw] = roundup(jiffy_end, tg->td->throtl_slice); } static inline void throtl_extend_slice(struct throtl_grp *tg, bool rw, unsigned long jiffy_end) { - tg->slice_end[rw] = roundup(jiffy_end, throtl_slice); + tg->slice_end[rw] = roundup(jiffy_end, tg->td->throtl_slice); throtl_log(&tg->service_queue, "[%c] extend slice start=%lu end=%lu jiffies=%lu", rw == READ ? 'R' : 'W', tg->slice_start[rw], @@ -718,19 +721,20 @@ static inline void throtl_trim_slice(struct throtl_grp *tg, bool rw) * is bad because it does not allow new slice to start. */ - throtl_set_slice_end(tg, rw, jiffies + throtl_slice); + throtl_set_slice_end(tg, rw, jiffies + tg->td->throtl_slice); time_elapsed = jiffies - tg->slice_start[rw]; - nr_slices = time_elapsed / throtl_slice; + nr_slices = time_elapsed / tg->td->throtl_slice; if (!nr_slices) return; - tmp = tg_bps_limit(tg, rw) * throtl_slice * nr_slices; + tmp = tg_bps_limit(tg, rw) * tg->td->throtl_slice * nr_slices; do_div(tmp, HZ); bytes_trim = tmp; - io_trim = (tg_iops_limit(tg, rw) * throtl_slice * nr_slices) / HZ; + io_trim = (tg_iops_limit(tg, rw) * tg->td->throtl_slice * nr_slices) / + HZ; if (!bytes_trim && !io_trim) return; @@ -745,7 +749,7 @@ static inline void throtl_trim_slice(struct throtl_grp *tg, bool rw) else tg->io_disp[rw] = 0; - tg->slice_start[rw] += nr_slices * throtl_slice; + tg->slice_start[rw] += nr_slices * tg->td->throtl_slice; throtl_log(&tg->service_queue, "[%c] trim slice nr=%lu bytes=%llu io=%lu start=%lu end=%lu jiffies=%lu", @@ -765,9 +769,9 @@ static bool tg_with_in_iops_limit(struct throtl_grp *tg, struct bio *bio, /* Slice has just started. Consider one slice interval */ if (!jiffy_elapsed) - jiffy_elapsed_rnd = throtl_slice; + jiffy_elapsed_rnd = tg->td->throtl_slice; - jiffy_elapsed_rnd = roundup(jiffy_elapsed_rnd, throtl_slice); + jiffy_elapsed_rnd = roundup(jiffy_elapsed_rnd, tg->td->throtl_slice); /* * jiffy_elapsed_rnd should not be a big value as minimum iops can be @@ -814,9 +818,9 @@ static bool tg_with_in_bps_limit(struct throtl_grp *tg, struct bio *bio, /* Slice has just started. Consider one slice interval */ if (!jiffy_elapsed) - jiffy_elapsed_rnd = throtl_slice; + jiffy_elapsed_rnd = tg->td->throtl_slice; - jiffy_elapsed_rnd = roundup(jiffy_elapsed_rnd, throtl_slice); + jiffy_elapsed_rnd = roundup(jiffy_elapsed_rnd, tg->td->throtl_slice); tmp = tg_bps_limit(tg, rw) * jiffy_elapsed_rnd; do_div(tmp, HZ); @@ -881,8 +885,10 @@ static bool tg_may_dispatch(struct throtl_grp *tg, struct bio *bio, if (throtl_slice_used(tg, rw) && !(tg->service_queue.nr_queued[rw])) throtl_start_new_slice(tg, rw); else { - if (time_before(tg->slice_end[rw], jiffies + throtl_slice)) - throtl_extend_slice(tg, rw, jiffies + throtl_slice); + if (time_before(tg->slice_end[rw], + jiffies + tg->td->throtl_slice)) + throtl_extend_slice(tg, rw, + jiffies + tg->td->throtl_slice); } if (tg_with_in_bps_limit(tg, bio, &bps_wait) && @@ -1632,7 +1638,7 @@ static bool throtl_can_upgrade(struct throtl_data *td, if (td->limit_index != LIMIT_HIGH) return false; - if (time_before(jiffies, td->high_downgrade_time + throtl_slice)) + if (time_before(jiffies, td->high_downgrade_time + td->throtl_slice)) return false; rcu_read_lock(); @@ -1689,8 +1695,9 @@ static bool throtl_downgrade_check_one(struct throtl_grp *tg) * If cgroup is below high limit, consider downgrade and throttle other * cgroups */ - if (time_after_eq(now, td->high_upgrade_time + throtl_slice) && - time_after_eq(now, tg_last_high_overflow_time(tg) + throtl_slice)) + if (time_after_eq(now, td->high_upgrade_time + td->throtl_slice) && + time_after_eq(now, tg_last_high_overflow_time(tg) + + td->throtl_slice)) return true; return false; } @@ -1723,10 +1730,11 @@ static void throtl_downgrade_check(struct throtl_grp *tg) return; if (!list_empty(&tg_to_blkg(tg)->blkcg->css.children)) return; - if (time_after(tg->last_check_time + throtl_slice, now)) + if (time_after(tg->last_check_time + tg->td->throtl_slice, now)) return; - if (time_before(now, tg_last_high_overflow_time(tg) + throtl_slice)) + if (time_before(now, tg_last_high_overflow_time(tg) + + tg->td->throtl_slice)) return; elapsed_time = now - tg->last_check_time; @@ -1965,6 +1973,7 @@ int blk_throtl_init(struct request_queue *q) q->td = td; td->queue = q; + td->throtl_slice = DFL_THROTL_SLICE; td->limit_valid[LIMIT_MAX] = true; td->limit_index = LIMIT_MAX; @@ -1985,6 +1994,30 @@ void blk_throtl_exit(struct request_queue *q) kfree(q->td); } +ssize_t blk_throtl_slice_show(struct request_queue *q, char *page) +{ + if (!q->td) + return -EINVAL; + return sprintf(page, "%ums\n", jiffies_to_msecs(q->td->throtl_slice)); +} + +ssize_t blk_throtl_slice_store(struct request_queue *q, + const char *page, size_t count) +{ + unsigned long v; + unsigned long t; + + if (!q->td) + return -EINVAL; + if (kstrtoul(page, 10, &v)) + return -EINVAL; + t = msecs_to_jiffies(v); + if (t == 0 || t > MAX_THROTL_SLICE) + return -EINVAL; + q->td->throtl_slice = t; + return count; +} + static int __init throtl_init(void) { kthrotld_workqueue = alloc_workqueue("kthrotld", WQ_MEM_RECLAIM, 0); diff --git a/block/blk.h b/block/blk.h index 74444c4..39c14dd 100644 --- a/block/blk.h +++ b/block/blk.h @@ -289,6 +289,9 @@ static inline struct io_context *create_io_context(gfp_t gfp_mask, int node) extern void blk_throtl_drain(struct request_queue *q); extern int blk_throtl_init(struct request_queue *q); extern void blk_throtl_exit(struct request_queue *q); +extern ssize_t blk_throtl_slice_show(struct request_queue *q, char *page); +extern ssize_t blk_throtl_slice_store(struct request_queue *q, + const char *page, size_t count); #else /* CONFIG_BLK_DEV_THROTTLING */ static inline void blk_throtl_drain(struct request_queue *q) { } static inline int blk_throtl_init(struct request_queue *q) { return 0; } -- 2.9.3