Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754099AbbDMKXG (ORCPT ); Mon, 13 Apr 2015 06:23:06 -0400 Received: from cn.fujitsu.com ([59.151.112.132]:61252 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1753493AbbDMKXE (ORCPT ); Mon, 13 Apr 2015 06:23:04 -0400 X-IronPort-AV: E=Sophos;i="5.04,848,1406563200"; d="scan'208";a="90587201" From: Zhao Lei To: "'Boaz Harrosh'" , "'Christoph Hellwig'" CC: , "'Jan Kara'" , "'Jens Axboe'" , "'LKML'" References: <016d01d07380$fc37fc40$f4a7f4c0$@cn.fujitsu.com> <552A57F8.7020002@plexistor.com> <552A839C.4070101@plexistor.com> In-Reply-To: Subject: RE: Regression caused by using node_to_bdi() Date: Mon, 13 Apr 2015 18:22:51 +0800 Message-ID: <030a01d075d3$cc1ebc60$645c3520$@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Outlook 15.0 Thread-Index: AQGFPDSkCPVR9AeIZuOecNLBimqRUwJHSBkKAYlPTLWdwm/twIAAOCdA Content-Language: zh-cn Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4232 Lines: 126 Hi, Boaz > -----Original Message----- > From: Zhao Lei [mailto:zhaolei@cn.fujitsu.com] > Sent: Monday, April 13, 2015 3:00 PM > To: 'Boaz Harrosh'; 'Christoph Hellwig' > Cc: 'linux-fsdevel@vger.kernel.org'; 'Jan Kara'; 'Jens Axboe'; 'LKML' > Subject: RE: Regression caused by using node_to_bdi() > > Hi, Boaz > > > -----Original Message----- > > From: Boaz Harrosh [mailto:boaz@plexistor.com] > > Sent: Sunday, April 12, 2015 10:39 PM > > To: Boaz Harrosh; Zhao Lei; 'Christoph Hellwig' > > Cc: linux-fsdevel@vger.kernel.org; 'Jan Kara'; 'Jens Axboe'; 'LKML' > > Subject: Re: Regression caused by using node_to_bdi() > > > > On 04/12/2015 02:33 PM, Boaz Harrosh wrote: > > > On 04/10/2015 02:25 PM, Zhao Lei wrote: > > >> Hi, Christoph Hellwig > > >> > > <> > > >> > > >> Is there some way to speed up it(inline, or some access some > > >> variant in struct directly, ...)? > > >> > > > > > > Christoph hi > > > > > > Both node_to_bdi() and sb_is_blkdev_sb() (and I_BDEV() && > > > blk_get_backing_dev_info()) Are an exported function calls. > > > > > > Can we not make blockdev_superblock->s_bdi == NULL, and then > > > optimize-out the call to sb_is_blkdev_sb() to only that case. > > > Something like: > > > > > > --- > > > > > > diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index > > > 32a8bbd..e0375e1 100644 > > > --- a/fs/fs-writeback.c > > > +++ b/fs/fs-writeback.c > > > @@ -78,7 +78,7 @@ int writeback_in_progress(struct backing_dev_info > > > *bdi) } EXPORT_SYMBOL(writeback_in_progress); > > > > > > -struct backing_dev_info *inode_to_bdi(struct inode *inode) > > > +struct backing_dev_info *__inode_to_bdi(struct inode *inode) > > > { > > > struct super_block *sb; > > > > > > @@ -92,7 +92,7 @@ struct backing_dev_info *inode_to_bdi(struct inode > > > *inode) #endif > > > return sb->s_bdi; > > > } > > > -EXPORT_SYMBOL_GPL(inode_to_bdi); > > > +EXPORT_SYMBOL_GPL(__inode_to_bdi); > > > > > > static inline struct inode *wb_inode(struct list_head *head) { > > > diff --git a/include/linux/backing-dev.h > > > b/include/linux/backing-dev.h index aff923a..7d172f5 100644 > > > --- a/include/linux/backing-dev.h > > > +++ b/include/linux/backing-dev.h > > > @@ -107,7 +107,16 @@ struct backing_dev_info { #endif }; > > > > > > -struct backing_dev_info *inode_to_bdi(struct inode *inode); > > > +struct backing_dev_info *__inode_to_bdi(struct inode *inode); > > > + > > > +static inline > > > +struct backing_dev_info *inode_to_bdi(struct inode *inode) { > > > + if (!inode || !inode->i_sb) > > > + return __inode_to_bdi(inode); > > > + > > > + return inode->i_sb->s_bdi; > > > +} > > > > > > > This patch actually boots. Lei could you please test to see if it > > fixes your slowness? > > > The good news is this patch passed compile and 10-time tests. > The bad news is it have more performance down(strange)... > > v3.19-rc1 : io_speed: valcnt=10 avg=214.688 > range=[211.460,216.190] diff= 2.24% stdev=1.417 cv=0.66% > v4.0-rc1 : io_speed: valcnt=10 avg=204.917 > range=[203.370,205.890] diff= 1.24% stdev=0.663 cv=0.32% > v4.0-rc1_00001_82ad06 : io_speed: valcnt=10 avg=189.337 > range=[186.280,192.060] diff= 3.10% stdev=2.305 cv=1.22% *<- this patch > > I applied this patch on top of v4.0-rc1. > A new bad news: This patch make filesystem unstable. My env entered to following command line in booting after apply this patch to v4.0-rc1: Welcome to emergency mode! After logging in, type "journalctl -xb: to view System logs, ... Give root password for maintenance (or press Control-D to continue) I confirmed this error message for more than 3 times. (and confirmed no-problem without this patch) In previous performance test(which get result in my last mail), I hadn't pay attention to that message, and just type Ctrl-D and begin test. Thanks Zhaolei > > Thanks > > Boaz > > > > > int __must_check bdi_init(struct backing_dev_info *bdi); void > > > bdi_destroy(struct backing_dev_info *bdi); > > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/