Linux-Fsdevel Archive on lore.kernel.org
 help / color / 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,
	Tejun Heo <tj@kernel.org>
Subject: [PATCH 08/19] writeback: make __wb_calc_thresh() take dirty_throttle_control
Date: Mon,  6 Apr 2015 16:04:23 -0400
Message-ID: <1428350674-8303-9-git-send-email-tj@kernel.org> (raw)
In-Reply-To: <1428350674-8303-1-git-send-email-tj@kernel.org>

wb_calc_thresh() calculates wb_thresh by scaling thresh according to
the wb's portion in the system-wide write bandwidth.  cgroup writeback
support would need to calculate wb_thresh against memcg domain too.
This patch renames wb_calc_thresh() to __wb_calc_thresh() and makes it
take dirty_throttle_control so that the function can later be updated
to calculate against different domains according to
dirty_throttle_control.

wb_calc_thresh() is now a thin wrapper around __wb_calc_thresh().

v2: The original version was incorrectly scaling dtc->dirty instead of
    dtc->thresh.  This was due to the extremely confusing function and
    variable names.  Added a rename patch and fixed this one.

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>
---
 mm/page-writeback.c | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 0fe7e60..33b1536 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -557,9 +557,8 @@ static unsigned long hard_dirty_limit(unsigned long thresh)
 }
 
 /**
- * wb_calc_thresh - @wb's share of dirty throttling threshold
- * @wb: bdi_writeback to query
- * @dirty: global dirty limit in pages
+ * __wb_calc_thresh - @wb's share of dirty throttling threshold
+ * @dtc: dirty_throttle_context of interest
  *
  * Returns @wb's dirty limit in pages. The term "dirty" in the context of
  * dirty balancing includes all PG_dirty, PG_writeback and NFS unstable pages.
@@ -578,9 +577,10 @@ static unsigned long hard_dirty_limit(unsigned long thresh)
  * The wb's share of dirty limit will be adapting to its throughput and
  * bounded by the bdi->min_ratio and/or bdi->max_ratio parameters, if set.
  */
-unsigned long wb_calc_thresh(struct bdi_writeback *wb, unsigned long thresh)
+static unsigned long __wb_calc_thresh(struct dirty_throttle_control *dtc)
 {
 	struct wb_domain *dom = &global_wb_domain;
+	unsigned long thresh = dtc->thresh;
 	u64 wb_thresh;
 	long numerator, denominator;
 	unsigned long wb_min_ratio, wb_max_ratio;
@@ -588,14 +588,14 @@ unsigned long wb_calc_thresh(struct bdi_writeback *wb, unsigned long thresh)
 	/*
 	 * Calculate this BDI's share of the thresh ratio.
 	 */
-	fprop_fraction_percpu(&dom->completions, &wb->completions,
+	fprop_fraction_percpu(&dom->completions, &dtc->wb->completions,
 			      &numerator, &denominator);
 
 	wb_thresh = (thresh * (100 - bdi_min_ratio)) / 100;
 	wb_thresh *= numerator;
 	do_div(wb_thresh, denominator);
 
-	wb_min_max_ratio(wb, &wb_min_ratio, &wb_max_ratio);
+	wb_min_max_ratio(dtc->wb, &wb_min_ratio, &wb_max_ratio);
 
 	wb_thresh += (thresh * wb_min_ratio) / 100;
 	if (wb_thresh > (thresh * wb_max_ratio) / 100)
@@ -604,6 +604,13 @@ unsigned long wb_calc_thresh(struct bdi_writeback *wb, unsigned long thresh)
 	return wb_thresh;
 }
 
+unsigned long wb_calc_thresh(struct bdi_writeback *wb, unsigned long thresh)
+{
+	struct dirty_throttle_control gdtc = { GDTC_INIT(wb),
+					       .thresh = thresh };
+	return __wb_calc_thresh(&gdtc);
+}
+
 /*
  *                           setpoint - dirty 3
  *        f(dirty) := 1.0 + (----------------)
@@ -1323,7 +1330,7 @@ static inline void wb_dirty_limits(struct dirty_throttle_control *dtc)
 	 *   wb_position_ratio() will let the dirtier task progress
 	 *   at some rate <= (write_bw / 2) for bringing down wb_dirty.
 	 */
-	dtc->wb_thresh = wb_calc_thresh(dtc->wb, dtc->thresh);
+	dtc->wb_thresh = __wb_calc_thresh(dtc);
 	dtc->wb_bg_thresh = dtc->thresh ?
 		div_u64((u64)dtc->wb_thresh * dtc->bg_thresh, dtc->thresh) : 0;
 
-- 
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: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

  parent reply index

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
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 01/19] memcg: make mem_cgroup_read_{stat|event}() iterate possible cpus instead of online Tejun Heo
2015-04-06 20:04 ` [PATCH 02/19] writeback: clean up wb_dirty_limit() Tejun Heo
2015-04-06 20:04 ` [PATCH 03/19] writeback: reorganize [__]wb_update_bandwidth() Tejun Heo
2015-04-06 20:04 ` [PATCH 04/19] writeback: implement wb_domain Tejun Heo
2015-04-06 20:04 ` [PATCH 05/19] writeback: move global_dirty_limit into wb_domain Tejun Heo
2015-04-06 20:04 ` [PATCH 06/19] writeback: consolidate dirty throttle parameters into dirty_throttle_control Tejun Heo
2015-04-06 20:04 ` [PATCH 07/19] writeback: add dirty_throttle_control->wb_bg_thresh Tejun Heo
2015-04-06 20:04 ` Tejun Heo [this message]
2015-04-06 20:04 ` [PATCH 09/19] writeback: add dirty_throttle_control->pos_ratio Tejun Heo
2015-04-06 20:04 ` [PATCH 10/19] writeback: add dirty_throttle_control->wb_completions Tejun Heo
2015-04-06 20:04 ` [PATCH 11/19] writeback: add dirty_throttle_control->dom Tejun Heo
2015-04-06 20:04 ` [PATCH 12/19] writeback: make __wb_writeout_inc() and hard_dirty_limit() take wb_domaas a parameter Tejun Heo
2015-04-06 20:04 ` [PATCH 13/19] writeback: separate out domain_dirty_limits() Tejun Heo
2015-04-06 20:04 ` [PATCH 14/19] writeback: move over_bground_thresh() to mm/page-writeback.c Tejun Heo
2015-04-06 20:04 ` [PATCH 15/19] writeback: update wb_over_bg_thresh() to use wb_domain aware operations Tejun Heo
2015-04-06 20:04 ` [PATCH 16/19] writeback: implement memcg wb_domain Tejun Heo
2015-04-06 20:04 ` [PATCH 17/19] writeback: reset wb_domain->dirty_limit[_tstmp] when memcg domain size changes Tejun Heo
2015-04-06 20:04 ` [PATCH 18/19] writeback: implement memcg writeback domain based throttling Tejun Heo
2015-04-06 20:04 ` [PATCH 19/19] mm: vmscan: disable memcg direct reclaim stalling if cgroup writeback support is in use Tejun Heo
2015-04-06 20:07 ` [PATCHSET 2/3 v2 block/for-4.1/core] writeback: cgroup writeback backpressure propagation Tejun Heo
2015-05-22 22:23 [PATCHSET 2/3 v3 block/for-4.2/core] " Tejun Heo
2015-05-22 22:23 ` [PATCH 08/19] writeback: make __wb_calc_thresh() take dirty_throttle_control 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=1428350674-8303-9-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=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 \
    /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

Linux-Fsdevel Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-fsdevel/0 linux-fsdevel/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-fsdevel linux-fsdevel/ https://lore.kernel.org/linux-fsdevel \
		linux-fsdevel@vger.kernel.org
	public-inbox-index linux-fsdevel

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-fsdevel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git