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authorTejun Heo <tj@kernel.org>2015-09-29 12:47:53 -0400
committerJens Axboe <axboe@fb.com>2015-10-12 10:31:13 -0600
commitd60d1bddd5b642711a237511845853755b25bf1f (patch)
treee5790b6d703d30fcd8c92f5760fdcc0e165fc912
parentb817525a4a80c04e4ca44192d97a1ffa9f2be572 (diff)
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: c2aa723a6093 ("writeback: implement memcg writeback domain based throttling") Signed-off-by: Jens Axboe <axboe@fb.com>
-rw-r--r--mm/page-writeback.c20
1 files changed, 11 insertions, 9 deletions
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 0f1a94e9f351..56c0bffa9f49 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -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)