brain-hackers_pepepper-mirror
/
linux-brain
mirror of https://github.com/brain-hackers/linux-brain.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

writeback: memcg dirty_throttle_control should be initialized with wb->memcg_completions 

MDTC_INIT() is used to initialize dirty_throttle_control for memcg
domains.  It used DTC_INIT_COMMON() to initialized mdtc->wb and
->wb_completions which is incorrect as DTC_INIT_COMMON() sets the
latter to wb->completions instead of wb->memcg_completions.  This can
lead to wildly incorrect results when calculating the proportion of
dirty memory the memcg domain should get.

Remove DTC_INIT_COMMON() and update MDTC_INIT() to initialize
mdtc->wb_completions to wb->memcg_completions.

Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: c2aa723a60 ("writeback: implement memcg writeback domain based throttling")
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Tejun Heo 2015-09-29 12:47:53 -04:00 committed by Jens Axboe
parent b817525a4a
commit d60d1bddd5
1 changed files with 11 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
mm/page-writeback.c
View File

@ -145,9 +145,6 @@ struct dirty_throttle_control {
unsigned long pos_ratio;
};
#define DTC_INIT_COMMON(__wb) .wb = (__wb), \
.wb_completions = &(__wb)->completions
/*
* Length of period for aging writeout fractions of bdis. This is an
* arbitrarily chosen number. The longer the period, the slower fractions will
@ -157,12 +154,16 @@ struct dirty_throttle_control {
#ifdef CONFIG_CGROUP_WRITEBACK
#define GDTC_INIT(__wb) .dom = &global_wb_domain, \
DTC_INIT_COMMON(__wb)
#define GDTC_INIT(__wb) .wb = (__wb), \
.dom = &global_wb_domain, \
.wb_completions = &(__wb)->completions
#define GDTC_INIT_NO_WB .dom = &global_wb_domain
#define MDTC_INIT(__wb, __gdtc) .dom = mem_cgroup_wb_domain(__wb), \
.gdtc = __gdtc, \
DTC_INIT_COMMON(__wb)
#define MDTC_INIT(__wb, __gdtc) .wb = (__wb), \
.dom = mem_cgroup_wb_domain(__wb), \
.wb_completions = &(__wb)->memcg_completions, \
.gdtc = __gdtc
static bool mdtc_valid(struct dirty_throttle_control *dtc)
{
@ -213,7 +214,8 @@ static void wb_min_max_ratio(struct bdi_writeback *wb,
#else /* CONFIG_CGROUP_WRITEBACK */
#define GDTC_INIT(__wb) DTC_INIT_COMMON(__wb)
#define GDTC_INIT(__wb) .wb = (__wb), \
.wb_completions = &(__wb)->completions
#define GDTC_INIT_NO_WB
#define MDTC_INIT(__wb, __gdtc)