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 02/18] writeback: reorganize [__]wb_update_bandwidth()
Date: Mon, 23 Mar 2015 01:07:31 -0400 [thread overview]
Message-ID: <1427087267-16592-3-git-send-email-tj@kernel.org> (raw)
In-Reply-To: <1427087267-16592-1-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 890cff1..3d9b360 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -1079,16 +1079,6 @@ 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 75349bb..82e0e39 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -154,14 +154,7 @@ int dirty_writeback_centisecs_handler(struct ctl_table *, int,
void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty);
unsigned long wb_dirty_limit(struct bdi_writeback *wb, unsigned long dirty);
-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 fd441ea..d9ebabe 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 @@ snapshot:
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,
--
2.1.0
--
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>
next prev parent reply other threads:[~2015-03-23 5:07 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-23 5:07 [PATCHSET 2/3 block/for-4.1/core] writeback: cgroup writeback backpressure propagation Tejun Heo
2015-03-23 5:07 ` [PATCH 01/18] memcg: make mem_cgroup_read_{stat|event}() iterate possible cpus instead of online Tejun Heo
2015-03-25 22:39 ` [PATCH 1.5/18] writeback: clean up wb_dirty_limit() Tejun Heo
2015-03-23 5:07 ` Tejun Heo [this message]
2015-03-23 5:07 ` [PATCH 03/18] writeback: implement wb_domain Tejun Heo
2015-03-23 5:07 ` [PATCH 04/18] writeback: move global_dirty_limit into wb_domain Tejun Heo
2015-03-23 5:07 ` [PATCH 05/18] writeback: consolidate dirty throttle parameters into dirty_throttle_control Tejun Heo
2015-03-23 5:07 ` [PATCH 06/18] writeback: add dirty_throttle_control->wb_bg_thresh Tejun Heo
2015-03-23 5:07 ` [PATCH 07/18] writeback: make __wb_dirty_limit() take dirty_throttle_control Tejun Heo
2015-03-25 22:42 ` [PATCH v2 07/18] writeback: make __wb_calc_thresh() " Tejun Heo
2015-03-23 5:07 ` [PATCH 08/18] writeback: add dirty_throttle_control->pos_ratio Tejun Heo
2015-03-23 5:07 ` [PATCH 09/18] writeback: add dirty_throttle_control->wb_completions Tejun Heo
2015-03-23 5:07 ` [PATCH 10/18] writeback: add dirty_throttle_control->dom Tejun Heo
2015-03-23 5:07 ` [PATCH 11/18] writeback: make __wb_writeout_inc() and hard_dirty_limit() take wb_domaas a parameter Tejun Heo
2015-03-23 5:07 ` [PATCH 12/18] writeback: separate out domain_dirty_limits() Tejun Heo
2015-03-23 5:07 ` [PATCH 13/18] writeback: move over_bground_thresh() to mm/page-writeback.c Tejun Heo
2015-03-23 5:07 ` [PATCH 14/18] writeback: update wb_over_bg_thresh() to use wb_domain aware operations Tejun Heo
2015-03-23 5:07 ` [PATCH 15/18] writeback: implement memcg wb_domain Tejun Heo
2015-03-23 5:07 ` [PATCH 16/18] writeback: reset wb_domain->dirty_limit[_tstmp] when memcg domain size changes Tejun Heo
2015-03-23 5:07 ` [PATCH 17/18] writeback: implement memcg writeback domain based throttling Tejun Heo
2015-03-23 5:07 ` [PATCH 18/18] mm: vmscan: remove memcg stalling on writeback pages during direct reclaim Tejun Heo
2015-03-23 5:27 ` Tejun Heo
2015-03-25 22:26 ` [PATCH v2 18/18] mm: vmscan: disable memcg direct reclaim stalling if cgroup writeback support is in use 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=1427087267-16592-3-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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
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).