From mboxrd@z Thu Jan 1 00:00:00 1970 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=-18.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 4B361C49EAF for ; Mon, 14 Jun 2021 11:28:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3471E6115B for ; Mon, 14 Jun 2021 11:28:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236193AbhFNL37 (ORCPT ); Mon, 14 Jun 2021 07:29:59 -0400 Received: from mail.kernel.org ([198.145.29.99]:44646 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234633AbhFNLP2 (ORCPT ); Mon, 14 Jun 2021 07:15:28 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 92D3661977; Mon, 14 Jun 2021 10:49:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1623667777; bh=qAZ6axj8wVCrYkcrpn7fqyX5J9L42vgeo36Fvv3Y9PQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DXkJMDuTGL9auECEA4U3uZHu6v2ucs6bEzDRm+m40osSBp1S6V42rt1rhGFoC7sne 5brB7GFXSlmktyiSSbiZh5kVsnsyHKwxJsYpFBZ8Bl209/3oklJob+HnTASqWfGqG3 6LY3J6c/0eL00RMOHQvIAvRc/da/NDH19PFJ2yIc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alexander Ullrich , Diego Ercolani , Jan Szubiak , Marco Rebhan , Matthias Ferdinand , Victor Westerhuis , Vojtech Pavlik , Coly Li , Christoph Hellwig , Kent Overstreet , Nix , Takashi Iwai , Jens Axboe , Rolf Fokkens , Thorsten Knabe Subject: [PATCH 5.12 071/173] bcache: remove bcache device self-defined readahead Date: Mon, 14 Jun 2021 12:26:43 +0200 Message-Id: <20210614102700.522177219@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210614102658.137943264@linuxfoundation.org> References: <20210614102658.137943264@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Coly Li commit 1616a4c2ab1a80893b6890ae93da40a2b1d0c691 upstream. 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 Reported-and-tested-by: Rolf Fokkens Reported-and-tested-by: Thorsten Knabe Signed-off-by: Coly Li Reviewed-by: Christoph Hellwig Cc: stable@vger.kernel.org Cc: Kent Overstreet Cc: Nix Cc: Takashi Iwai Link: https://lore.kernel.org/r/20210607125052.21277-2-colyli@suse.de Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- 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(-) --- 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; --- a/drivers/md/bcache/request.c +++ b/drivers/md/bcache/request.c @@ -880,7 +880,6 @@ static int cached_dev_cache_miss(struct 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 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 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); --- 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 c 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_sta 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 time 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 ca 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); --- 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; }; --- 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_ &sysfs_running, &sysfs_state, &sysfs_label, - &sysfs_readahead, #ifdef CONFIG_BCACHE_DEBUG &sysfs_verify, &sysfs_bypass_torture_test,