Messages in this thread | | | From | Yafang Shao <> | Date | Mon, 9 Oct 2017 18:44:23 +0800 | Subject | Re: [PATCH] mm/page-writeback.c: fix bug caused by disable periodic writeback |
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2017-10-09 17:56 GMT+08:00 Jan Kara <jack@suse.cz>: > On Sat 07-10-17 06:58:04, Yafang Shao wrote: >> After disable periodic writeback by writing 0 to >> dirty_writeback_centisecs, the handler wb_workfn() will not be >> entered again until the dirty background limit reaches or >> sync syscall is executed or no enough free memory available or >> vmscan is triggered. >> So the periodic writeback can't be enabled by writing a non-zero >> value to dirty_writeback_centisecs >> As it can be disabled by sysctl, it should be able to enable by >> sysctl as well. >> >> Signed-off-by: Yafang Shao <laoar.shao@gmail.com> >> --- >> mm/page-writeback.c | 8 +++++++- >> 1 file changed, 7 insertions(+), 1 deletion(-) >> >> diff --git a/mm/page-writeback.c b/mm/page-writeback.c >> index 0b9c5cb..e202f37 100644 >> --- a/mm/page-writeback.c >> +++ b/mm/page-writeback.c >> @@ -1972,7 +1972,13 @@ bool wb_over_bg_thresh(struct bdi_writeback *wb) >> int dirty_writeback_centisecs_handler(struct ctl_table *table, int write, >> void __user *buffer, size_t *length, loff_t *ppos) >> { >> - proc_dointvec(table, write, buffer, length, ppos); >> + unsigned int old_interval = dirty_writeback_interval; >> + int ret; >> + >> + ret = proc_dointvec(table, write, buffer, length, ppos); >> + if (!ret && !old_interval && dirty_writeback_interval) >> + wakeup_flusher_threads(0, WB_REASON_PERIODIC); >> + > > I agree it is good to schedule some writeback. However Jens has some > changes queued in linux-block tree in this area so your change won't apply. > So please base your changes on his tree. >
Do you mean this tree git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git ?
I have checked his tree and find nothing need to change on my patch.
> Honza > -- > Jan Kara <jack@suse.com> > SUSE Labs, CR
Thanks Yafang
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