From patchwork Mon Jun 7 10:35:38 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Coly Li X-Patchwork-Id: 12303095 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 18C00C47095 for ; Mon, 7 Jun 2021 10:36:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 04953611C0 for ; Mon, 7 Jun 2021 10:36:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230428AbhFGKiF (ORCPT ); Mon, 7 Jun 2021 06:38:05 -0400 Received: from smtp-out2.suse.de ([195.135.220.29]:49598 "EHLO smtp-out2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230313AbhFGKiF (ORCPT ); Mon, 7 Jun 2021 06:38:05 -0400 Received: from relay2.suse.de (unknown [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id 04E5F1FDA5; Mon, 7 Jun 2021 10:36:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1623062173; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=9Gppx7Ttk9TZku//qRtEDYU3mzmgVx76ovzRtKNksq4=; b=1StGtw8ETTC5mrULRHCUxEt23M+3RyCWDfqLSuDtcteg3rwZxyFqTICnnr/0U3B5Uef37I FSBpFyue57Yl3S+xMjNZSO0EXMZANCCz2aYjXd9gCQ5Om0yevRv8DIywuGH6F0fSQk7dFO 2uXniSWLsezIBMg2AnccHe2Q90saCBs= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1623062173; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=9Gppx7Ttk9TZku//qRtEDYU3mzmgVx76ovzRtKNksq4=; b=2CadWXWgCqSaeAqp51xQwSft+vJPucbvb+DRAM5NpwmepFy/kMACcZat/mhCXfhHhYmCGN E3gsuih606RfyKCg== Received: from localhost.localdomain (unknown [10.163.16.22]) by relay2.suse.de (Postfix) with ESMTP id 20D61A3B83; Mon, 7 Jun 2021 10:36:07 +0000 (UTC) From: Coly Li To: axboe@kernel.dk Cc: linux-bcache@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, Coly Li , Alexander Ullrich , Diego Ercolani , Jan Szubiak , Marco Rebhan , Matthias Ferdinand , Victor Westerhuis , Vojtech Pavlik , Rolf Fokkens , Thorsten Knabe , stable@vger.kernel.org, Christoph Hellwig , Kent Overstreet , Nix , Takashi Iwai Subject: [PATCH v5 1/2] bcache: remove bcache device self-defined readahead Date: Mon, 7 Jun 2021 18:35:38 +0800 Message-Id: <20210607103539.12823-2-colyli@suse.de> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20210607103539.12823-1-colyli@suse.de> References: <20210607103539.12823-1-colyli@suse.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org For read cache missing, bcache defines a readahead size for the read I/O request to the backing device for the missing data. This readahead size is initialized to 0, and almost no one uses it to avoid unnecessary read amplifying onto backing device and write amplifying onto cache device. Considering upper layer file system code has readahead logic allready and works fine with readahead_cache_policy sysfile interface, we don't have to keep bcache self-defined readahead anymore. This patch removes the bcache self-defined readahead for cache missing request for backing device, and the readahead sysfs file interfaces are removed as well. This is the preparation for next patch to fix potential kernel panic due to oversized request in a simpler method. Reported-by: Alexander Ullrich Reported-by: Diego Ercolani Reported-by: Jan Szubiak Reported-by: Marco Rebhan Reported-by: Matthias Ferdinand Reported-by: Victor Westerhuis Reported-by: Vojtech Pavlik Signed-off-by: Coly Li Reported-and-tested-by: Rolf Fokkens Reported-and-tested-by: Thorsten Knabe Cc: stable@vger.kernel.org Cc: Christoph Hellwig Cc: Kent Overstreet Cc: Nix Cc: Takashi Iwai Reviewed-by: Christoph Hellwig --- Changlog, v1, the initial version by hint from Christoph Hellwig. drivers/md/bcache/bcache.h | 1 - drivers/md/bcache/request.c | 13 +------------ drivers/md/bcache/stats.c | 14 -------------- drivers/md/bcache/stats.h | 1 - drivers/md/bcache/sysfs.c | 4 ---- 5 files changed, 1 insertion(+), 32 deletions(-) diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h index 0a4551e165ab..5fc989a6d452 100644 --- a/drivers/md/bcache/bcache.h +++ b/drivers/md/bcache/bcache.h @@ -364,7 +364,6 @@ struct cached_dev { /* The rest of this all shows up in sysfs */ unsigned int sequential_cutoff; - unsigned int readahead; unsigned int io_disable:1; unsigned int verify:1; diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c index 29c231758293..ab8ff18df32a 100644 --- a/drivers/md/bcache/request.c +++ b/drivers/md/bcache/request.c @@ -880,7 +880,6 @@ static int cached_dev_cache_miss(struct btree *b, struct search *s, struct bio *bio, unsigned int sectors) { int ret = MAP_CONTINUE; - unsigned int reada = 0; struct cached_dev *dc = container_of(s->d, struct cached_dev, disk); struct bio *miss, *cache_bio; @@ -892,14 +891,7 @@ static int cached_dev_cache_miss(struct btree *b, struct search *s, goto out_submit; } - if (!(bio->bi_opf & REQ_RAHEAD) && - !(bio->bi_opf & (REQ_META|REQ_PRIO)) && - s->iop.c->gc_stats.in_use < CUTOFF_CACHE_READA) - reada = min_t(sector_t, dc->readahead >> 9, - get_capacity(bio->bi_bdev->bd_disk) - - bio_end_sector(bio)); - - s->insert_bio_sectors = min(sectors, bio_sectors(bio) + reada); + s->insert_bio_sectors = min(sectors, bio_sectors(bio)); s->iop.replace_key = KEY(s->iop.inode, bio->bi_iter.bi_sector + s->insert_bio_sectors, @@ -933,9 +925,6 @@ static int cached_dev_cache_miss(struct btree *b, struct search *s, if (bch_bio_alloc_pages(cache_bio, __GFP_NOWARN|GFP_NOIO)) goto out_put; - if (reada) - bch_mark_cache_readahead(s->iop.c, s->d); - s->cache_miss = miss; s->iop.bio = cache_bio; bio_get(cache_bio); diff --git a/drivers/md/bcache/stats.c b/drivers/md/bcache/stats.c index 503aafe188dc..4c7ee5fedb9d 100644 --- a/drivers/md/bcache/stats.c +++ b/drivers/md/bcache/stats.c @@ -46,7 +46,6 @@ read_attribute(cache_misses); read_attribute(cache_bypass_hits); read_attribute(cache_bypass_misses); read_attribute(cache_hit_ratio); -read_attribute(cache_readaheads); read_attribute(cache_miss_collisions); read_attribute(bypassed); @@ -64,7 +63,6 @@ SHOW(bch_stats) DIV_SAFE(var(cache_hits) * 100, var(cache_hits) + var(cache_misses))); - var_print(cache_readaheads); var_print(cache_miss_collisions); sysfs_hprint(bypassed, var(sectors_bypassed) << 9); #undef var @@ -86,7 +84,6 @@ static struct attribute *bch_stats_files[] = { &sysfs_cache_bypass_hits, &sysfs_cache_bypass_misses, &sysfs_cache_hit_ratio, - &sysfs_cache_readaheads, &sysfs_cache_miss_collisions, &sysfs_bypassed, NULL @@ -113,7 +110,6 @@ void bch_cache_accounting_clear(struct cache_accounting *acc) acc->total.cache_misses = 0; acc->total.cache_bypass_hits = 0; acc->total.cache_bypass_misses = 0; - acc->total.cache_readaheads = 0; acc->total.cache_miss_collisions = 0; acc->total.sectors_bypassed = 0; } @@ -145,7 +141,6 @@ static void scale_stats(struct cache_stats *stats, unsigned long rescale_at) scale_stat(&stats->cache_misses); scale_stat(&stats->cache_bypass_hits); scale_stat(&stats->cache_bypass_misses); - scale_stat(&stats->cache_readaheads); scale_stat(&stats->cache_miss_collisions); scale_stat(&stats->sectors_bypassed); } @@ -168,7 +163,6 @@ static void scale_accounting(struct timer_list *t) move_stat(cache_misses); move_stat(cache_bypass_hits); move_stat(cache_bypass_misses); - move_stat(cache_readaheads); move_stat(cache_miss_collisions); move_stat(sectors_bypassed); @@ -209,14 +203,6 @@ void bch_mark_cache_accounting(struct cache_set *c, struct bcache_device *d, mark_cache_stats(&c->accounting.collector, hit, bypass); } -void bch_mark_cache_readahead(struct cache_set *c, struct bcache_device *d) -{ - struct cached_dev *dc = container_of(d, struct cached_dev, disk); - - atomic_inc(&dc->accounting.collector.cache_readaheads); - atomic_inc(&c->accounting.collector.cache_readaheads); -} - void bch_mark_cache_miss_collision(struct cache_set *c, struct bcache_device *d) { struct cached_dev *dc = container_of(d, struct cached_dev, disk); diff --git a/drivers/md/bcache/stats.h b/drivers/md/bcache/stats.h index abfaabf7e7fc..ca4f435f7216 100644 --- a/drivers/md/bcache/stats.h +++ b/drivers/md/bcache/stats.h @@ -7,7 +7,6 @@ struct cache_stat_collector { atomic_t cache_misses; atomic_t cache_bypass_hits; atomic_t cache_bypass_misses; - atomic_t cache_readaheads; atomic_t cache_miss_collisions; atomic_t sectors_bypassed; }; diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c index cc89f3156d1a..05ac1d6fbbf3 100644 --- a/drivers/md/bcache/sysfs.c +++ b/drivers/md/bcache/sysfs.c @@ -137,7 +137,6 @@ rw_attribute(io_disable); rw_attribute(discard); rw_attribute(running); rw_attribute(label); -rw_attribute(readahead); rw_attribute(errors); rw_attribute(io_error_limit); rw_attribute(io_error_halflife); @@ -260,7 +259,6 @@ SHOW(__bch_cached_dev) var_printf(partial_stripes_expensive, "%u"); var_hprint(sequential_cutoff); - var_hprint(readahead); sysfs_print(running, atomic_read(&dc->running)); sysfs_print(state, states[BDEV_STATE(&dc->sb)]); @@ -365,7 +363,6 @@ STORE(__cached_dev) sysfs_strtoul_clamp(sequential_cutoff, dc->sequential_cutoff, 0, UINT_MAX); - d_strtoi_h(readahead); if (attr == &sysfs_clear_stats) bch_cache_accounting_clear(&dc->accounting); @@ -538,7 +535,6 @@ static struct attribute *bch_cached_dev_files[] = { &sysfs_running, &sysfs_state, &sysfs_label, - &sysfs_readahead, #ifdef CONFIG_BCACHE_DEBUG &sysfs_verify, &sysfs_bypass_torture_test,