From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chao Yu Subject: Re: [PATCH] f2fs: avoid hungtask problem caused by losing wake_up Date: Tue, 23 Feb 2016 13:44:08 +0800 Message-ID: <009501d16dfd$52a518c0$f7ef4a40$@samsung.com> References: <1456200476-9811-1-git-send-email-heyunlei@huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from sog-mx-1.v43.ch3.sourceforge.com ([172.29.43.191] helo=mx.sourceforge.net) by sfs-ml-2.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1aY5mU-0000JS-DD for linux-f2fs-devel@lists.sourceforge.net; Tue, 23 Feb 2016 05:45:06 +0000 Received: from mailout4.samsung.com ([203.254.224.34]) by sog-mx-1.v43.ch3.sourceforge.com with esmtps (TLSv1:AES128-SHA:128) (Exim 4.76) id 1aY5mS-0006id-JK for linux-f2fs-devel@lists.sourceforge.net; Tue, 23 Feb 2016 05:45:06 +0000 Received: from epcpsbgm2new.samsung.com (epcpsbgm2 [203.254.230.27]) by mailout4.samsung.com (Oracle Communications Messaging Server 7.0.5.31.0 64bit (built May 5 2014)) with ESMTP id <0O2Z02914JYEPN50@mailout4.samsung.com> for linux-f2fs-devel@lists.sourceforge.net; Tue, 23 Feb 2016 14:44:56 +0900 (KST) In-reply-to: <1456200476-9811-1-git-send-email-heyunlei@huawei.com> Content-language: zh-cn List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net To: 'Yunlei He' , jaegeuk@kernel.org, linux-f2fs-devel@lists.sourceforge.net Cc: 'Biao He' Hi Yunlei, > -----Original Message----- > From: Yunlei He [mailto:heyunlei@huawei.com] > Sent: Tuesday, February 23, 2016 12:08 PM > To: chao2.yu@samsung.com; jaegeuk@kernel.org; linux-f2fs-devel@lists.sourceforge.net > Cc: bintian.wang@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 > Signed-off-by: Biao He > --- > 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