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author | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-12-14 03:23:01 (GMT) |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-12-14 03:23:01 (GMT) |
commit | 93c222c0e126c1c24ac454acf013f2c85e57bd8b (patch) | |
tree | 920c429de92857aaf74e64a0f4f9fbaec7032fcf /mm/backing-dev.c | |
parent | f89c2b39ce676cb08b6ed8848cde76dcb21cc672 (diff) | |
parent | 9f9499ae8e6415cefc4fe0a96ad0e27864353c89 (diff) | |
download | linux-93c222c0e126c1c24ac454acf013f2c85e57bd8b.tar.xz |
Merge 4.4-rc5 into staging-next
We want those fixes in here for testing.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm/backing-dev.c')
-rw-r--r-- | mm/backing-dev.c | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/mm/backing-dev.c b/mm/backing-dev.c index 8ed2ffd..7340353 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -957,8 +957,9 @@ EXPORT_SYMBOL(congestion_wait); * jiffies for either a BDI to exit congestion of the given @sync queue * or a write to complete. * - * In the absence of zone congestion, cond_resched() is called to yield - * the processor if necessary but otherwise does not sleep. + * In the absence of zone congestion, a short sleep or a cond_resched is + * performed to yield the processor and to allow other subsystems to make + * a forward progress. * * The return value is 0 if the sleep is for the full timeout. Otherwise, * it is the number of jiffies that were still remaining when the function @@ -978,7 +979,19 @@ long wait_iff_congested(struct zone *zone, int sync, long timeout) */ if (atomic_read(&nr_wb_congested[sync]) == 0 || !test_bit(ZONE_CONGESTED, &zone->flags)) { - cond_resched(); + + /* + * Memory allocation/reclaim might be called from a WQ + * context and the current implementation of the WQ + * concurrency control doesn't recognize that a particular + * WQ is congested if the worker thread is looping without + * ever sleeping. Therefore we have to do a short sleep + * here rather than calling cond_resched(). + */ + if (current->flags & PF_WQ_WORKER) + schedule_timeout(1); + else + cond_resched(); /* In case we scheduled, work out time remaining */ ret = timeout - (jiffies - start); |