Hi Kim, One comment as following: > -----Original Message----- > From: Jaegeuk Kim [mailto:jaegeuk.kim@xxxxxxxxxxx] > Sent: Wednesday, December 18, 2013 8:12 AM > To: linux-fsdevel@xxxxxxxxxxxxxxx > Cc: linux-kernel@xxxxxxxxxxxxxxx; linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx > Subject: Re: [f2fs-dev] [PATCH] f2fs: introduce a new direct_IO write path > > Change log from v1: > o fix NOSPC error handling > > >From b8511a74fe98b67247a9feeed58441e8f5ffd705 Mon Sep 17 00:00:00 2001 > From: Jaegeuk Kim <jaegeuk.kim@xxxxxxxxxxx> > Date: Mon, 16 Dec 2013 19:04:05 +0900 > Subject: [PATCH] f2fs: introduce a new direct_IO write path > Cc: linux-fsdevel@xxxxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx, > linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx > > Previously, f2fs doesn't support direct IOs with high performance, which > throws > every write requests via the buffered write path, resulting in highly > performance degradation due to memory opeations like copy_from_user. > > This patch introduces a new direct IO path in which every write requests > are > processed by generic blockdev_direct_IO() with enhanced get_block > function. > > The get_data_block() in f2fs handles: > 1. if original data blocks are allocates, then give them to blockdev. > 2. otherwise, > a. preallocate requested block addresses > b. do not use extent cache for better performance > c. give the block addresses to blockdev > > This policy induces that: > - new allocated data are sequentially written to the disk > - updated data are randomly written to the disk. > - f2fs gives consistency on its file meta, not file data. > > Signed-off-by: Jaegeuk Kim <jaegeuk.kim@xxxxxxxxxxx> > --- > fs/f2fs/data.c | 152 > ++++++++++++++++++++++++++++++++++++++++-------------- > fs/f2fs/f2fs.h | 2 + > fs/f2fs/segment.c | 23 ++++++--- > 3 files changed, 129 insertions(+), 48 deletions(-) > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c > index 15956fa..a0950bc 100644 > --- a/fs/f2fs/data.c > +++ b/fs/f2fs/data.c > @@ -570,74 +570,151 @@ repeat: > return page; > } > > +static int __allocate_data_block(struct dnode_of_data *dn) > +{ > + struct f2fs_sb_info *sbi = F2FS_SB(dn->inode->i_sb); > + struct f2fs_summary sum; > + block_t new_blkaddr; > + struct node_info ni; > + int type; > + > + if (unlikely(is_inode_flag_set(F2FS_I(dn->inode), FI_NO_ALLOC))) > + return -EPERM; > + if (unlikely(!inc_valid_block_count(sbi, dn->inode, 1))) > + return -ENOSPC; > + > + __set_data_blkaddr(dn, NEW_ADDR); > + dn->data_blkaddr = NEW_ADDR; > + > + get_node_info(sbi, dn->nid, &ni); > + set_summary(&sum, dn->nid, dn->ofs_in_node, ni.version); > + > + type = CURSEG_WARM_DATA; If so, our cold data will be written to WARM_DATA segment. How about check segment type here? > + > + allocate_data_block(sbi, NULL, NULL_ADDR, &new_blkaddr, &sum, type); > + > + /* direct IO doesn't use extent cache to maximize the performance */ > + set_inode_flag(F2FS_I(dn->inode), FI_NO_EXTENT); > + update_extent_cache(new_blkaddr, dn); > + clear_inode_flag(F2FS_I(dn->inode), FI_NO_EXTENT); > + > + dn->data_blkaddr = new_blkaddr; > + return 0; > +} > + [snip] -- 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
