From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S943101AbcJ0Wj4 (ORCPT ); Thu, 27 Oct 2016 18:39:56 -0400 Received: from mail.kernel.org ([198.145.29.136]:60342 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S943002AbcJ0Wjx (ORCPT ); Thu, 27 Oct 2016 18:39:53 -0400 Date: Fri, 28 Oct 2016 07:39:46 +0900 From: Jaegeuk Kim To: Chao Yu Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Subject: Re: [PATCH] f2fs: use BIO_MAX_PAGES for bio allocation Message-ID: <20161027223946.GB18682@jaegeuk> References: <20161018184836.12886-1-jaegeuk@kernel.org> <51e0b1df-e19e-bd42-4120-638bcbde6c19@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <51e0b1df-e19e-bd42-4120-638bcbde6c19@huawei.com> User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 27, 2016 at 06:28:04PM +0800, Chao Yu wrote: > On 2016/10/19 2:48, Jaegeuk Kim wrote: > > We don't need to allocate bio partially in order to maximize sequential writes. > > We are going to allocate bio with max size supposing that there will be more > opportunity to merge small IOs into one bio. Otherwise, if MAX_BIO_BLOCKS is > smaller than BIO_MAX_PAGES, less IOs can be merged. Is my understanding correct? Yes. When I test /dev/md0 with ramdisks, this happens and results in lower performance than other filesystems. Thanks, > > Thanks, > > > > > Signed-off-by: Jaegeuk Kim > > --- > > fs/f2fs/checkpoint.c | 2 +- > > fs/f2fs/data.c | 4 +--- > > fs/f2fs/node.c | 3 +-- > > fs/f2fs/segment.c | 4 ++-- > > fs/f2fs/segment.h | 17 +++-------------- > > 5 files changed, 8 insertions(+), 22 deletions(-) > > > > diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c > > index 654f5d7..157b7fd 100644 > > --- a/fs/f2fs/checkpoint.c > > +++ b/fs/f2fs/checkpoint.c > > @@ -228,7 +228,7 @@ void ra_meta_pages_cond(struct f2fs_sb_info *sbi, pgoff_t index) > > f2fs_put_page(page, 0); > > > > if (readahead) > > - ra_meta_pages(sbi, index, MAX_BIO_BLOCKS(sbi), META_POR, true); > > + ra_meta_pages(sbi, index, BIO_MAX_PAGES, META_POR, true); > > } > > > > static int f2fs_write_meta_page(struct page *page, > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c > > index 77cd9ac..fe8ce5a 100644 > > --- a/fs/f2fs/data.c > > +++ b/fs/f2fs/data.c > > @@ -307,10 +307,8 @@ void f2fs_submit_page_mbio(struct f2fs_io_info *fio) > > __submit_merged_bio(io); > > alloc_new: > > if (io->bio == NULL) { > > - int bio_blocks = MAX_BIO_BLOCKS(sbi); > > - > > io->bio = __bio_alloc(sbi, fio->new_blkaddr, > > - bio_blocks, is_read); > > + BIO_MAX_PAGES, is_read); > > io->fio = *fio; > > } > > > > diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c > > index 69c42e2..285e2a5 100644 > > --- a/fs/f2fs/node.c > > +++ b/fs/f2fs/node.c > > @@ -2101,7 +2101,6 @@ int restore_node_summary(struct f2fs_sb_info *sbi, > > struct f2fs_node *rn; > > struct f2fs_summary *sum_entry; > > block_t addr; > > - int bio_blocks = MAX_BIO_BLOCKS(sbi); > > int i, idx, last_offset, nrpages; > > > > /* scan the node segment */ > > @@ -2110,7 +2109,7 @@ int restore_node_summary(struct f2fs_sb_info *sbi, > > sum_entry = &sum->entries[0]; > > > > for (i = 0; i < last_offset; i += nrpages, addr += nrpages) { > > - nrpages = min(last_offset - i, bio_blocks); > > + nrpages = min(last_offset - i, BIO_MAX_PAGES); > > > > /* readahead node pages */ > > ra_meta_pages(sbi, addr, nrpages, META_POR, true); > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c > > index 7a7e3f1..a21a1a3 100644 > > --- a/fs/f2fs/segment.c > > +++ b/fs/f2fs/segment.c > > @@ -2355,10 +2355,10 @@ static void build_sit_entries(struct f2fs_sb_info *sbi) > > int sit_blk_cnt = SIT_BLK_CNT(sbi); > > unsigned int i, start, end; > > unsigned int readed, start_blk = 0; > > - int nrpages = MAX_BIO_BLOCKS(sbi) * 8; > > > > do { > > - readed = ra_meta_pages(sbi, start_blk, nrpages, META_SIT, true); > > + readed = ra_meta_pages(sbi, start_blk, BIO_MAX_PAGES, > > + META_SIT, true); > > > > start = start_blk * sit_i->sents_per_block; > > end = (start_blk + readed) * sit_i->sents_per_block; > > diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h > > index a6efb5c..d8ff069 100644 > > --- a/fs/f2fs/segment.h > > +++ b/fs/f2fs/segment.h > > @@ -102,8 +102,6 @@ > > (((sector_t)blk_addr) << F2FS_LOG_SECTORS_PER_BLOCK) > > #define SECTOR_TO_BLOCK(sectors) \ > > (sectors >> F2FS_LOG_SECTORS_PER_BLOCK) > > -#define MAX_BIO_BLOCKS(sbi) \ > > - ((int)min((int)max_hw_blocks(sbi), BIO_MAX_PAGES)) > > > > /* > > * indicate a block allocation direction: RIGHT and LEFT. > > @@ -698,13 +696,6 @@ static inline bool sec_usage_check(struct f2fs_sb_info *sbi, unsigned int secno) > > return false; > > } > > > > -static inline unsigned int max_hw_blocks(struct f2fs_sb_info *sbi) > > -{ > > - struct block_device *bdev = sbi->sb->s_bdev; > > - struct request_queue *q = bdev_get_queue(bdev); > > - return SECTOR_TO_BLOCK(queue_max_sectors(q)); > > -} > > - > > /* > > * It is very important to gather dirty pages and write at once, so that we can > > * submit a big bio without interfering other data writes. > > @@ -722,7 +713,7 @@ static inline int nr_pages_to_skip(struct f2fs_sb_info *sbi, int type) > > else if (type == NODE) > > return 8 * sbi->blocks_per_seg; > > else if (type == META) > > - return 8 * MAX_BIO_BLOCKS(sbi); > > + return 8 * BIO_MAX_PAGES; > > else > > return 0; > > } > > @@ -739,11 +730,9 @@ static inline long nr_pages_to_write(struct f2fs_sb_info *sbi, int type, > > return 0; > > > > nr_to_write = wbc->nr_to_write; > > - > > + desired = BIO_MAX_PAGES; > > if (type == NODE) > > - desired = 2 * max_hw_blocks(sbi); > > - else > > - desired = MAX_BIO_BLOCKS(sbi); > > + desired <<= 1; > > > > wbc->nr_to_write = desired; > > return desired - nr_to_write; > >