From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qc0-f170.google.com (mail-qc0-f170.google.com [209.85.216.170]) by kanga.kvack.org (Postfix) with ESMTP id EEBDA6B00BF for ; Mon, 6 Apr 2015 16:00:13 -0400 (EDT) Received: by qcyk17 with SMTP id k17so15128394qcy.1 for ; Mon, 06 Apr 2015 13:00:13 -0700 (PDT) Received: from mail-qk0-x233.google.com (mail-qk0-x233.google.com. [2607:f8b0:400d:c09::233]) by mx.google.com with ESMTPS id h7si5137483qge.80.2015.04.06.12.59.49 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 06 Apr 2015 12:59:50 -0700 (PDT) Received: by qku63 with SMTP id 63so30980854qku.3 for ; Mon, 06 Apr 2015 12:59:49 -0700 (PDT) From: Tejun Heo Subject: [PATCH 34/49] writeback: make bdi->min/max_ratio handling cgroup writeback aware Date: Mon, 6 Apr 2015 15:58:23 -0400 Message-Id: <1428350318-8215-35-git-send-email-tj@kernel.org> In-Reply-To: <1428350318-8215-1-git-send-email-tj@kernel.org> References: <1428350318-8215-1-git-send-email-tj@kernel.org> Sender: owner-linux-mm@kvack.org List-ID: To: axboe@kernel.dk Cc: linux-kernel@vger.kernel.org, jack@suse.cz, hch@infradead.org, hannes@cmpxchg.org, linux-fsdevel@vger.kernel.org, vgoyal@redhat.com, lizefan@huawei.com, cgroups@vger.kernel.org, linux-mm@kvack.org, mhocko@suse.cz, clm@fb.com, fengguang.wu@intel.com, david@fromorbit.com, gthelen@google.com, Tejun Heo bdi->min/max_ratio are user-configurable per-bdi knobs which regulate dirty limit of each bdi. For cgroup writeback, they need to be further distributed across wb's (bdi_writeback's) belonging to the configured bdi. This patch introduces wb_min_max_ratio() which distributes bdi->min/max_ratio according to a wb's proportion in the total active bandwidth of its bdi. v2: Update wb_min_max_ratio() to fix a bug where both min and max were assigned the min value and avoid calculations when possible. Signed-off-by: Tejun Heo Cc: Jens Axboe Cc: Jan Kara --- mm/page-writeback.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 46 insertions(+), 4 deletions(-) diff --git a/mm/page-writeback.c b/mm/page-writeback.c index ba2b83d..8755f80 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -155,6 +155,46 @@ static unsigned long writeout_period_time = 0; */ #define VM_COMPLETIONS_PERIOD_LEN (3*HZ) +#ifdef CONFIG_CGROUP_WRITEBACK + +static void wb_min_max_ratio(struct bdi_writeback *wb, + unsigned long *minp, unsigned long *maxp) +{ + unsigned long this_bw = wb->avg_write_bandwidth; + unsigned long tot_bw = atomic_long_read(&wb->bdi->tot_write_bandwidth); + unsigned long long min = wb->bdi->min_ratio; + unsigned long long max = wb->bdi->max_ratio; + + /* + * @wb may already be clean by the time control reaches here and + * the total may not include its bw. + */ + if (this_bw < tot_bw) { + if (min) { + min *= this_bw; + do_div(min, tot_bw); + } + if (max < 100) { + max *= this_bw; + do_div(max, tot_bw); + } + } + + *minp = min; + *maxp = max; +} + +#else /* CONFIG_CGROUP_WRITEBACK */ + +static void wb_min_max_ratio(struct bdi_writeback *wb, + unsigned long *minp, unsigned long *maxp) +{ + *minp = wb->bdi->min_ratio; + *maxp = wb->bdi->max_ratio; +} + +#endif /* CONFIG_CGROUP_WRITEBACK */ + /* * In a memory zone, there is a certain amount of pages we consider * available for the page cache, which is essentially the number of @@ -539,9 +579,9 @@ static unsigned long hard_dirty_limit(unsigned long thresh) */ unsigned long wb_dirty_limit(struct bdi_writeback *wb, unsigned long dirty) { - struct backing_dev_info *bdi = wb->bdi; u64 wb_dirty; long numerator, denominator; + unsigned long wb_min_ratio, wb_max_ratio; /* * Calculate this BDI's share of the dirty ratio. @@ -552,9 +592,11 @@ unsigned long wb_dirty_limit(struct bdi_writeback *wb, unsigned long dirty) wb_dirty *= numerator; do_div(wb_dirty, denominator); - wb_dirty += (dirty * bdi->min_ratio) / 100; - if (wb_dirty > (dirty * bdi->max_ratio) / 100) - wb_dirty = dirty * bdi->max_ratio / 100; + wb_min_max_ratio(wb, &wb_min_ratio, &wb_max_ratio); + + wb_dirty += (dirty * wb_min_ratio) / 100; + if (wb_dirty > (dirty * wb_max_ratio) / 100) + wb_dirty = dirty * wb_max_ratio / 100; return wb_dirty; } -- 2.1.0 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org