Hi Yunlei, > -----Original Message----- > From: Yunlei He [mailto:heyun...@huawei.com] > Sent: Tuesday, February 23, 2016 12:08 PM > To: chao2...@samsung.com; jaeg...@kernel.org; > linux-f2fs-devel@lists.sourceforge.net > Cc: bintian.w...@huawei.com; Yunlei He; Biao He > Subject: [f2fs-dev] [PATCH] f2fs: avoid hungtask problem caused by losing > wake_up > > The D state of wait_on_all_pages_writeback should be waken by > function f2fs_write_end_io when all writeback pages have been > succesfully written to device. It's possible that wake_up comes > between get_pages and io_schedule. Maybe in this case it will > lost wake_up and still in D state even if all pages have been > write back to device, and finally, the whole system will be into > the hungtask state.
I haven't encountered such issue so far, do you suffer this in real world? > > if (!get_pages(sbi, F2FS_WRITEBACK)) > break; > <--------- wake_up wake_up will put all tasks linked in sbi->cp_wait on run-queue, so here it should be save to call io_schedule, after being rescheduled, it will get the chance to check above condition to break out. Thanks, > io_schedule(); > > Signed-off-by: Yunlei He <heyun...@huawei.com> > Signed-off-by: Biao He <hebi...@huawei.com> > --- > fs/f2fs/checkpoint.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c > index 2bac8a1..f55355d 100644 > --- a/fs/f2fs/checkpoint.c > +++ b/fs/f2fs/checkpoint.c > @@ -920,7 +920,7 @@ static void wait_on_all_pages_writeback(struct > f2fs_sb_info *sbi) > if (!get_pages(sbi, F2FS_WRITEBACK)) > break; > > - io_schedule(); > + io_schedule_timeout(5*HZ); > } > finish_wait(&sbi->cp_wait, &wait); > } > -- > 1.9.1 ------------------------------------------------------------------------------ Site24x7 APM Insight: Get Deep Visibility into Application Performance APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month Monitor end-to-end web transactions and take corrective actions now Troubleshoot faster and improve end-user experience. Signup Now! http://pubads.g.doubleclick.net/gampad/clk?id=272487151&iu=/4140 _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
