Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751642AbbDLOja (ORCPT ); Sun, 12 Apr 2015 10:39:30 -0400 Received: from mail-wi0-f171.google.com ([209.85.212.171]:35698 "EHLO mail-wi0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751330AbbDLOj1 (ORCPT ); Sun, 12 Apr 2015 10:39:27 -0400 Message-ID: <552A839C.4070101@plexistor.com> Date: Sun, 12 Apr 2015 17:39:24 +0300 From: Boaz Harrosh User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 MIME-Version: 1.0 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() References: <016d01d07380$fc37fc40$f4a7f4c0$@cn.fujitsu.com> <552A57F8.7020002@plexistor.com> In-Reply-To: <552A57F8.7020002@plexistor.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2255 Lines: 80 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? 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/