linux-fsdevel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Tejun Heo <tj@kernel.org>
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,
	khlebnikov@yandex-team.ru, Tejun Heo <tj@kernel.org>
Subject: [PATCH 03/19] writeback: reorganize [__]wb_update_bandwidth()
Date: Fri, 22 May 2015 18:23:20 -0400	[thread overview]
Message-ID: <1432333416-6221-4-git-send-email-tj@kernel.org> (raw)
In-Reply-To: <1432333416-6221-1-git-send-email-tj@kernel.org>

__wb_update_bandwidth() is called from two places -
fs/fs-writeback.c::balance_dirty_pages() and
mm/page-writeback.c::wb_writeback().  The latter updates only the
write bandwidth while the former also deals with the dirty ratelimit.
The two callsites are distinguished by whether @thresh parameter is
zero or not, which is cryptic.  In addition, the two files define
their own different versions of wb_update_bandwidth() on top of
__wb_update_bandwidth(), which is confusing to say the least.  This
patch cleans up [__]wb_update_bandwidth() in the following ways.

* __wb_update_bandwidth() now takes explicit @update_ratelimit
  parameter to gate dirty ratelimit handling.

* mm/page-writeback.c::wb_update_bandwidth() is flattened into its
  caller - balance_dirty_pages().

* fs/fs-writeback.c::wb_update_bandwidth() is moved to
  mm/page-writeback.c and __wb_update_bandwidth() is made static.

* While at it, add a lockdep assertion to __wb_update_bandwidth().

Except for the lockdep addition, this is pure reorganization and
doesn't introduce any behavioral changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jan Kara <jack@suse.cz>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Greg Thelen <gthelen@google.com>
---
 fs/fs-writeback.c         | 10 ----------
 include/linux/writeback.h |  9 +--------
 mm/page-writeback.c       | 45 ++++++++++++++++++++++-----------------------
 3 files changed, 23 insertions(+), 41 deletions(-)

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index b1b3b81..cd89484 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -1088,16 +1088,6 @@ static bool over_bground_thresh(struct bdi_writeback *wb)
 }
 
 /*
- * Called under wb->list_lock. If there are multiple wb per bdi,
- * only the flusher working on the first wb should do it.
- */
-static void wb_update_bandwidth(struct bdi_writeback *wb,
-				unsigned long start_time)
-{
-	__wb_update_bandwidth(wb, 0, 0, 0, 0, 0, start_time);
-}
-
-/*
  * Explicit flushing or periodic writeback of "old" data.
  *
  * Define "old": the first time one of an inode's pages is dirtied, we mark the
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index 0435c85..80adf3d 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -157,14 +157,7 @@ int dirty_writeback_centisecs_handler(struct ctl_table *, int,
 void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty);
 unsigned long wb_calc_thresh(struct bdi_writeback *wb, unsigned long thresh);
 
-void __wb_update_bandwidth(struct bdi_writeback *wb,
-			   unsigned long thresh,
-			   unsigned long bg_thresh,
-			   unsigned long dirty,
-			   unsigned long bdi_thresh,
-			   unsigned long bdi_dirty,
-			   unsigned long start_time);
-
+void wb_update_bandwidth(struct bdi_writeback *wb, unsigned long start_time);
 void page_writeback_init(void);
 void balance_dirty_pages_ratelimited(struct address_space *mapping);
 
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index c7745a7..bebdd41 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -1160,19 +1160,22 @@ static void wb_update_dirty_ratelimit(struct bdi_writeback *wb,
 	trace_bdi_dirty_ratelimit(wb->bdi, dirty_rate, task_ratelimit);
 }
 
-void __wb_update_bandwidth(struct bdi_writeback *wb,
-			   unsigned long thresh,
-			   unsigned long bg_thresh,
-			   unsigned long dirty,
-			   unsigned long wb_thresh,
-			   unsigned long wb_dirty,
-			   unsigned long start_time)
+static void __wb_update_bandwidth(struct bdi_writeback *wb,
+				  unsigned long thresh,
+				  unsigned long bg_thresh,
+				  unsigned long dirty,
+				  unsigned long wb_thresh,
+				  unsigned long wb_dirty,
+				  unsigned long start_time,
+				  bool update_ratelimit)
 {
 	unsigned long now = jiffies;
 	unsigned long elapsed = now - wb->bw_time_stamp;
 	unsigned long dirtied;
 	unsigned long written;
 
+	lockdep_assert_held(&wb->list_lock);
+
 	/*
 	 * rate-limit, only update once every 200ms.
 	 */
@@ -1189,7 +1192,7 @@ void __wb_update_bandwidth(struct bdi_writeback *wb,
 	if (elapsed > HZ && time_before(wb->bw_time_stamp, start_time))
 		goto snapshot;
 
-	if (thresh) {
+	if (update_ratelimit) {
 		global_update_bandwidth(thresh, dirty, now);
 		wb_update_dirty_ratelimit(wb, thresh, bg_thresh, dirty,
 					  wb_thresh, wb_dirty,
@@ -1203,20 +1206,9 @@ void __wb_update_bandwidth(struct bdi_writeback *wb,
 	wb->bw_time_stamp = now;
 }
 
-static void wb_update_bandwidth(struct bdi_writeback *wb,
-				unsigned long thresh,
-				unsigned long bg_thresh,
-				unsigned long dirty,
-				unsigned long wb_thresh,
-				unsigned long wb_dirty,
-				unsigned long start_time)
+void wb_update_bandwidth(struct bdi_writeback *wb, unsigned long start_time)
 {
-	if (time_is_after_eq_jiffies(wb->bw_time_stamp + BANDWIDTH_INTERVAL))
-		return;
-	spin_lock(&wb->list_lock);
-	__wb_update_bandwidth(wb, thresh, bg_thresh, dirty,
-			      wb_thresh, wb_dirty, start_time);
-	spin_unlock(&wb->list_lock);
+	__wb_update_bandwidth(wb, 0, 0, 0, 0, 0, start_time, false);
 }
 
 /*
@@ -1467,8 +1459,15 @@ static void balance_dirty_pages(struct address_space *mapping,
 		if (dirty_exceeded && !wb->dirty_exceeded)
 			wb->dirty_exceeded = 1;
 
-		wb_update_bandwidth(wb, dirty_thresh, background_thresh,
-				    nr_dirty, wb_thresh, wb_dirty, start_time);
+		if (time_is_before_jiffies(wb->bw_time_stamp +
+					   BANDWIDTH_INTERVAL)) {
+			spin_lock(&wb->list_lock);
+			__wb_update_bandwidth(wb, dirty_thresh,
+					      background_thresh, nr_dirty,
+					      wb_thresh, wb_dirty, start_time,
+					      true);
+			spin_unlock(&wb->list_lock);
+		}
 
 		dirty_ratelimit = wb->dirty_ratelimit;
 		pos_ratio = wb_position_ratio(wb, dirty_thresh,
-- 
2.4.0

--
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: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

  parent reply	other threads:[~2015-05-22 22:23 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-05-22 22:23 [PATCHSET 2/3 v3 block/for-4.2/core] writeback: cgroup writeback backpressure propagation Tejun Heo
2015-05-22 22:23 ` [PATCH 01/19] memcg: make mem_cgroup_read_{stat|event}() iterate possible cpus instead of online Tejun Heo
     [not found]   ` <1432333416-6221-2-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2015-05-22 23:12     ` Johannes Weiner
2015-06-17 14:41   ` Michal Hocko
2015-05-22 22:23 ` [PATCH 02/19] writeback: clean up wb_dirty_limit() Tejun Heo
2015-05-22 22:23 ` Tejun Heo [this message]
2015-05-22 22:23 ` [PATCH 04/19] writeback: implement wb_domain Tejun Heo
2015-05-22 22:23 ` [PATCH 05/19] writeback: move global_dirty_limit into wb_domain Tejun Heo
2015-05-22 22:23 ` [PATCH 06/19] writeback: consolidate dirty throttle parameters into dirty_throttle_control Tejun Heo
2015-05-22 22:23 ` [PATCH 07/19] writeback: add dirty_throttle_control->wb_bg_thresh Tejun Heo
2015-05-22 22:23 ` [PATCH 08/19] writeback: make __wb_calc_thresh() take dirty_throttle_control Tejun Heo
2015-05-22 22:23 ` [PATCH 09/19] writeback: add dirty_throttle_control->pos_ratio Tejun Heo
2015-05-22 22:23 ` [PATCH 10/19] writeback: add dirty_throttle_control->wb_completions Tejun Heo
2015-05-22 22:23 ` [PATCH 11/19] writeback: add dirty_throttle_control->dom Tejun Heo
2015-05-22 22:23 ` [PATCH 12/19] writeback: make __wb_writeout_inc() and hard_dirty_limit() take wb_domaas a parameter Tejun Heo
2015-05-22 22:23 ` [PATCH 13/19] writeback: separate out domain_dirty_limits() Tejun Heo
2015-05-22 22:23 ` [PATCH 14/19] writeback: move over_bground_thresh() to mm/page-writeback.c Tejun Heo
2015-05-22 22:23 ` [PATCH 15/19] writeback: update wb_over_bg_thresh() to use wb_domain aware operations Tejun Heo
2015-05-22 22:23 ` [PATCH 16/19] writeback: implement memcg wb_domain Tejun Heo
2015-05-22 22:23 ` [PATCH 17/19] writeback: reset wb_domain->dirty_limit[_tstmp] when memcg domain size changes Tejun Heo
2015-05-22 22:23 ` [PATCH 18/19] writeback: implement memcg writeback domain based throttling Tejun Heo
2015-05-22 22:23 ` [PATCH 19/19] mm: vmscan: disable memcg direct reclaim stalling if cgroup writeback support is in use Tejun Heo
  -- strict thread matches above, loose matches on Subject: below --
2015-04-06 20:04 [PATCHSET 2/3 v2 block/for-4.1/core] writeback: cgroup writeback backpressure propagation Tejun Heo
2015-04-06 20:04 ` [PATCH 03/19] writeback: reorganize [__]wb_update_bandwidth() Tejun Heo

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1432333416-6221-4-git-send-email-tj@kernel.org \
    --to=tj@kernel.org \
    --cc=axboe@kernel.dk \
    --cc=cgroups@vger.kernel.org \
    --cc=clm@fb.com \
    --cc=david@fromorbit.com \
    --cc=fengguang.wu@intel.com \
    --cc=gthelen@google.com \
    --cc=hannes@cmpxchg.org \
    --cc=hch@infradead.org \
    --cc=jack@suse.cz \
    --cc=khlebnikov@yandex-team.ru \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=lizefan@huawei.com \
    --cc=mhocko@suse.cz \
    --cc=vgoyal@redhat.com \
    --subject='Re: [PATCH 03/19] writeback: reorganize [__]wb_update_bandwidth()' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).