Hi, Boaz > -----Original Message----- > From: Boaz Harrosh [mailto:boaz@xxxxxxxxxxxxx] > Sent: Sunday, April 12, 2015 10:39 PM > To: Boaz Harrosh; Zhao Lei; 'Christoph Hellwig' > Cc: linux-fsdevel@xxxxxxxxxxxxxxx; '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. > 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-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
