From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vyacheslav Dubeyko Subject: Re: Strange "flush" process bahaviour Date: Mon, 01 Apr 2013 10:06:11 +0400 Message-ID: <1364796371.2202.16.camel@slavad-ubuntu> References: <20121128205943.GZ4028@wloczykij> <1354172459.2077.11.camel@slavad-ubuntu> <20130328120700.GK1672@wloczykij> <20130329074249.GL1672@wloczykij> <1364544910.11128.9.camel@slavad-ubuntu> <20130329103710.GM1672@wloczykij> <1364556557.11128.28.camel@slavad-ubuntu> <20130329135722.GN1672@wloczykij> <1D751B59-8E60-4D32-80CA-734BD25EE12C@dubeyko.com> <20130331132609.GA1781@wloczykij> Reply-To: slava-yeENwD64cLxBDgjK7y7TUQ@public.gmane.org Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=dubeyko.com; s=default; h=Mime-Version:Content-Transfer-Encoding:Content-Type:References:In-Reply-To:Date:Cc:To:Reply-To:From:Subject:Message-ID; bh=uup9lxzn+6w+GgeFOnZ0iFDWFrmilePeD6f8rfpYgzg=; b=at3hup2Vo4BZzLLAt2VaxcyurEGQNbPjrCp27eOtf+s//oCi8AEzwdBATxzBO0foo1CYk95YHqHb52lofYfY5+33ilUtucW6QVsgmwX8fAevXE2dUZVuoXRWUIh2cjfa; In-Reply-To: <20130331132609.GA1781@wloczykij> Sender: linux-nilfs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Piotr Szymaniak Cc: linux-nilfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org On Sun, 2013-03-31 at 15:26 +0200, Piotr Szymaniak wrote: [snip] > > Hrm, maybe this is btrfs realated then? But I suppose I don't have any > btrfs on the second machine with flush issues. > If you detected issue with flush-8:0 kernel thread then it is a NILFS2 related issue, as I understand. Because flush-8:0 processes /dev/sda drive and you have NILFS2 partition on /dev/sda3 (/dev/sda3 on / type nilfs2 (rw,noatime,nodiratime,gcpid=16150)). > I had a system freeze yesterday and right after reboot flush is back. > So it looks like I can reproduce it (something makes the flush thing > while booting. Maybe I can catch some debug info there?). Right now I'm > going back to 3.4.x series kernel. > The visible symptoms of the issue (flush kernel thread "abnormal" activity) is not a reason of the issue. Such "abnormal" activity of flush kernel thread takes place because in nilfs_mdt_write_page() and nilfs_write_page() can be called with wbc->for_kupdate or wbc->for_background flags. It is made simply redirty_page_for_writepage() for such case. The real issue hides in other NILFS2 subsystem. And only clear understanding of file system operation that initiates such "abnormal" activity of flush kernel thread can be a basis for further debugging and investigation of the issue. With the best regards, Vyacheslav Dubeyko. > > Piotr Szymaniak. -- To unsubscribe from this list: send the line "unsubscribe linux-nilfs" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html