[5/6] f2fs: add a kernel thread to issue discard commands asynchronously

Message ID	20170112224407.54026-5-jaegeuk@kernel.org (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-fsdevel-owner@kernel.org> From: Jaegeuk Kim <jaegeuk@kernel.org> To: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Cc: Jaegeuk Kim <jaegeuk@kernel.org> Subject: [PATCH 5/6] f2fs: add a kernel thread to issue discard commands asynchronously Date: Thu, 12 Jan 2017 14:44:06 -0800 Message-Id: <20170112224407.54026-5-jaegeuk@kernel.org> In-Reply-To: <20170112224407.54026-1-jaegeuk@kernel.org> References: <20170112224407.54026-1-jaegeuk@kernel.org> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index e7b403cbd70f..ef5e3709c161 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -129,6 +129,7 @@ enum { }; #define MAX_DISCARD_BLOCKS(sbi) (1 << (sbi)->log_blocks_per_seg) +#define DISCARD_ISSUE_RATE 8 #define DEF_CP_INTERVAL 60 /* 60 secs */ #define DEF_IDLE_INTERVAL 5 /* 5 secs */ @@ -177,18 +178,28 @@ struct discard_entry { int len; /* # of consecutive blocks of the discard */ }; +enum { + D_PREP, + D_SUBMIT, + D_DONE, +}; + struct discard_cmd { struct list_head list; /* command list */ struct completion wait; /* compleation */ block_t lstart; /* logical start address */ block_t len; /* length */ struct bio *bio; /* bio */ + int state; /* state */ }; struct discard_cmd_control { + struct task_struct *f2fs_issue_discard; /* discard thread */ struct list_head discard_entry_list; /* 4KB discard entry list */ int nr_discards; /* # of discards in the list */ struct list_head discard_cmd_list; /* discard cmd list */ + wait_queue_head_t discard_wait_queue; /* waiting queue for wake-up */ + struct mutex cmd_lock; int max_discards; /* max. discards to be issued */ }; diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index e3bec31de961..74364006bfa6 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -628,7 +628,7 @@ static void locate_dirty_segment(struct f2fs_sb_info *sbi, unsigned int segno) mutex_unlock(&dirty_i->seglist_lock); } -static struct discard_cmd *__add_discard_cmd(struct f2fs_sb_info *sbi, +static void __add_discard_cmd(struct f2fs_sb_info *sbi, struct bio *bio, block_t lstart, block_t len) { struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info; @@ -638,12 +638,30 @@ static struct discard_cmd *__add_discard_cmd(struct f2fs_sb_info *sbi, dc = f2fs_kmem_cache_alloc(discard_cmd_slab, GFP_NOFS); INIT_LIST_HEAD(&dc->list); dc->bio = bio; + bio->bi_private = dc; dc->lstart = lstart; dc->len = len; + dc->state = D_PREP; init_completion(&dc->wait); + + mutex_lock(&dcc->cmd_lock); list_add_tail(&dc->list, cmd_list); + mutex_unlock(&dcc->cmd_lock); +} + +static void __remove_discard_cmd(struct f2fs_sb_info *sbi, struct discard_cmd *dc) +{ + int err = dc->bio->bi_error; - return dc; + if (err == -EOPNOTSUPP) + err = 0; + + if (err) + f2fs_msg(sbi->sb, KERN_INFO, + "Issue discard failed, ret: %d", err); + bio_put(dc->bio); + list_del(&dc->list); + kmem_cache_free(discard_cmd_slab, dc); } /* This should be covered by global mutex, &sit_i->sentry_lock */ @@ -653,31 +671,28 @@ void f2fs_wait_discard_bio(struct f2fs_sb_info *sbi, block_t blkaddr) struct list_head *wait_list = &(dcc->discard_cmd_list); struct discard_cmd *dc, *tmp; + mutex_lock(&dcc->cmd_lock); list_for_each_entry_safe(dc, tmp, wait_list, list) { - struct bio *bio = dc->bio; - int err; - if (!completion_done(&dc->wait)) { - if ((dc->lstart <= blkaddr && - blkaddr < dc->lstart + dc->len) || - blkaddr == NULL_ADDR) + if (blkaddr == NULL_ADDR) { + if (dc->state == D_PREP) { + dc->state = D_SUBMIT; + submit_bio(dc->bio); + } + wait_for_completion_io(&dc->wait); + + __remove_discard_cmd(sbi, dc); + continue; + } + + if (dc->lstart <= blkaddr && blkaddr < dc->lstart + dc->len) { + if (dc->state == D_SUBMIT) wait_for_completion_io(&dc->wait); else - continue; + __remove_discard_cmd(sbi, dc); } - - err = bio->bi_error; - if (err == -EOPNOTSUPP) - err = 0; - - if (err) - f2fs_msg(sbi->sb, KERN_INFO, - "Issue discard failed, ret: %d", err); - - bio_put(bio); - list_del(&dc->list); - kmem_cache_free(discard_cmd_slab, dc); } + mutex_unlock(&dcc->cmd_lock); } static void f2fs_submit_discard_endio(struct bio *bio) @@ -685,8 +700,48 @@ static void f2fs_submit_discard_endio(struct bio *bio) struct discard_cmd *dc = (struct discard_cmd *)bio->bi_private; complete(&dc->wait); + dc->state = D_DONE; } +static int issue_discard_thread(void *data) +{ + struct f2fs_sb_info *sbi = data; + struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info; + wait_queue_head_t *q = &dcc->discard_wait_queue; + struct list_head *cmd_list = &dcc->discard_cmd_list; + struct discard_cmd *dc, *tmp; + struct blk_plug plug; + int iter = 0; +repeat: + if (kthread_should_stop()) + return 0; + + blk_start_plug(&plug); + + mutex_lock(&dcc->cmd_lock); + list_for_each_entry_safe(dc, tmp, cmd_list, list) { + if (dc->state == D_PREP) { + dc->state = D_SUBMIT; + submit_bio(dc->bio); + if (iter++ > DISCARD_ISSUE_RATE) + break; + } else if (dc->state == D_DONE) { + __remove_discard_cmd(sbi, dc); + } + } + mutex_unlock(&dcc->cmd_lock); + + blk_finish_plug(&plug); + + iter = 0; + congestion_wait(BLK_RW_SYNC, HZ/50); + + wait_event_interruptible(*q, + kthread_should_stop() || !list_empty(&dcc->discard_cmd_list)); + goto repeat; +} + + /* this function is copied from blkdev_issue_discard from block/blk-lib.c */ static int __f2fs_issue_discard_async(struct f2fs_sb_info *sbi, struct block_device *bdev, block_t blkstart, block_t blklen) @@ -707,13 +762,11 @@ static int __f2fs_issue_discard_async(struct f2fs_sb_info *sbi, SECTOR_FROM_BLOCK(blklen), GFP_NOFS, 0, &bio); if (!err && bio) { - struct discard_cmd *dc = __add_discard_cmd(sbi, bio, - lblkstart, blklen); - - bio->bi_private = dc; bio->bi_end_io = f2fs_submit_discard_endio; bio->bi_opf |= REQ_SYNC; - submit_bio(bio); + + __add_discard_cmd(sbi, bio, lblkstart, blklen); + wake_up(&SM_I(sbi)->dcc_info->discard_wait_queue); } return err; } @@ -920,14 +973,11 @@ void clear_prefree_segments(struct f2fs_sb_info *sbi, struct cp_control *cpc) struct list_head *head = &(SM_I(sbi)->dcc_info->discard_entry_list); struct discard_entry *entry, *this; struct dirty_seglist_info *dirty_i = DIRTY_I(sbi); - struct blk_plug plug; unsigned long *prefree_map = dirty_i->dirty_segmap[PRE]; unsigned int start = 0, end = -1; unsigned int secno, start_segno; bool force = (cpc->reason == CP_DISCARD); - blk_start_plug(&plug); - mutex_lock(&dirty_i->seglist_lock); while (1) { @@ -980,12 +1030,11 @@ void clear_prefree_segments(struct f2fs_sb_info *sbi, struct cp_control *cpc) SM_I(sbi)->dcc_info->nr_discards -= entry->len; kmem_cache_free(discard_entry_slab, entry); } - - blk_finish_plug(&plug); } int create_discard_cmd_control(struct f2fs_sb_info *sbi) { + dev_t dev = sbi->sb->s_bdev->bd_dev; struct discard_cmd_control *dcc; int err = 0; @@ -1000,11 +1049,22 @@ int create_discard_cmd_control(struct f2fs_sb_info *sbi) INIT_LIST_HEAD(&dcc->discard_entry_list); INIT_LIST_HEAD(&dcc->discard_cmd_list); + mutex_init(&dcc->cmd_lock); dcc->nr_discards = 0; dcc->max_discards = 0; + init_waitqueue_head(&dcc->discard_wait_queue); SM_I(sbi)->dcc_info = dcc; init_thread: + dcc->f2fs_issue_discard = kthread_run(issue_discard_thread, sbi, + "f2fs_discard-%u:%u", MAJOR(dev), MINOR(dev)); + if (IS_ERR(dcc->f2fs_issue_discard)) { + err = PTR_ERR(dcc->f2fs_issue_discard); + kfree(dcc); + SM_I(sbi)->dcc_info = NULL; + return err; + } + return err; } @@ -1012,6 +1072,12 @@ void destroy_discard_cmd_control(struct f2fs_sb_info *sbi, bool free) { struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info; + if (dcc && dcc->f2fs_issue_discard) { + struct task_struct *discard_thread = dcc->f2fs_issue_discard; + + dcc->f2fs_issue_discard = NULL; + kthread_stop(discard_thread); + } if (free) { kfree(dcc); SM_I(sbi)->dcc_info = NULL;

[5/6] f2fs: add a kernel thread to issue discard commands asynchronously

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