Hi Jaegeuk Changman, > -----Original Message----- > From: Chao Yu [mailto:chao2.yu@xxxxxxxxxxx] > Sent: Thursday, July 03, 2014 6:59 PM > To: Jaegeuk Kim; Changman Lee > Cc: linux-fsdevel@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx > Subject: [f2fs-dev] [PATCH] f2fs: reduce competition among node page writes > > We do not need to block on ->node_write among different node page writers e.g. > fsync/flush, unless we have a node page writer from write_checkpoint. > So it's better use rw_semaphore instead of mutex type for ->node_write to > promote performance. If you could have time to help explaining the problem of this patch, I will be appreciated for that. Another question is what is ->writepages in sbi used for? I'm not quite clear. Thanks, > > Signed-off-by: Chao Yu <chao2.yu@xxxxxxxxxxx> > --- > fs/f2fs/checkpoint.c | 6 +++--- > fs/f2fs/f2fs.h | 2 +- > fs/f2fs/node.c | 4 ++-- > fs/f2fs/super.c | 2 +- > 4 files changed, 7 insertions(+), 7 deletions(-) > > diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c > index 0b4710c..eec406b 100644 > --- a/fs/f2fs/checkpoint.c > +++ b/fs/f2fs/checkpoint.c > @@ -714,10 +714,10 @@ retry_flush_dents: > * until finishing nat/sit flush. > */ > retry_flush_nodes: > - mutex_lock(&sbi->node_write); > + down_write(&sbi->node_write); > > if (get_pages(sbi, F2FS_DIRTY_NODES)) { > - mutex_unlock(&sbi->node_write); > + up_write(&sbi->node_write); > sync_node_pages(sbi, 0, &wbc); > goto retry_flush_nodes; > } > @@ -726,7 +726,7 @@ retry_flush_nodes: > > static void unblock_operations(struct f2fs_sb_info *sbi) > { > - mutex_unlock(&sbi->node_write); > + up_write(&sbi->node_write); > f2fs_unlock_all(sbi); > } > > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h > index ae3b4ac..ca30b5a 100644 > --- a/fs/f2fs/f2fs.h > +++ b/fs/f2fs/f2fs.h > @@ -444,7 +444,7 @@ struct f2fs_sb_info { > struct inode *meta_inode; /* cache meta blocks */ > struct mutex cp_mutex; /* checkpoint procedure lock */ > struct rw_semaphore cp_rwsem; /* blocking FS operations */ > - struct mutex node_write; /* locking node writes */ > + struct rw_semaphore node_write; /* locking node writes */ > struct mutex writepages; /* mutex for writepages() */ > bool por_doing; /* recovery is doing or not */ > wait_queue_head_t cp_wait; > diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c > index a90f51d..7b5b5de 100644 > --- a/fs/f2fs/node.c > +++ b/fs/f2fs/node.c > @@ -1231,12 +1231,12 @@ static int f2fs_write_node_page(struct page *page, > if (wbc->for_reclaim) > goto redirty_out; > > - mutex_lock(&sbi->node_write); > + down_read(&sbi->node_write); > set_page_writeback(page); > write_node_page(sbi, page, &fio, nid, ni.blk_addr, &new_addr); > set_node_addr(sbi, &ni, new_addr, is_fsync_dnode(page)); > dec_page_count(sbi, F2FS_DIRTY_NODES); > - mutex_unlock(&sbi->node_write); > + up_read(&sbi->node_write); > unlock_page(page); > return 0; > > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c > index 8f96d93..bed9413 100644 > --- a/fs/f2fs/super.c > +++ b/fs/f2fs/super.c > @@ -947,7 +947,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent) > mutex_init(&sbi->gc_mutex); > mutex_init(&sbi->writepages); > mutex_init(&sbi->cp_mutex); > - mutex_init(&sbi->node_write); > + init_rwsem(&sbi->node_write); > sbi->por_doing = false; > spin_lock_init(&sbi->stat_lock); > > -- > 1.7.9.5 > > > > ------------------------------------------------------------------------------ > Open source business process management suite built on Java and Eclipse > Turn processes into business applications with Bonita BPM Community Edition > Quickly connect people, data, and systems into organized workflows > Winner of BOSSIE, CODIE, OW2 and Gartner awards > http://p.sf.net/sfu/Bonitasoft > _______________________________________________ > Linux-f2fs-devel mailing list > Linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel -- 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
