From patchwork Fri Oct 21 10:34:06 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Begunkov X-Patchwork-Id: 13014590 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EE0CBC433FE for ; Fri, 21 Oct 2022 10:36:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229810AbiJUKgZ (ORCPT ); Fri, 21 Oct 2022 06:36:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43012 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229956AbiJUKgY (ORCPT ); Fri, 21 Oct 2022 06:36:24 -0400 Received: from mail-wr1-x435.google.com (mail-wr1-x435.google.com [IPv6:2a00:1450:4864:20::435]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C1B3F1A3E24; Fri, 21 Oct 2022 03:36:18 -0700 (PDT) Received: by mail-wr1-x435.google.com with SMTP id j7so4218223wrr.3; Fri, 21 Oct 2022 03:36:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=Dbgij4KdCuUgIto/9QTZly2/sdw9SHJOJXzPvbzOwA0=; b=TdDeffCwT0HzaCa7kEAmaBrZcGFasxW+K+LaBBZViyzAeKspc/DZr+YsQ3MOoQtN5r 8O/gjSjabUQjqevTVYQXI6AdrzyP3DLVHR0bbSicHjSCTcLBIK3PKvpf6Ctphs8xU+bp GmPCssPjIfgaYUOlIuTGISGdtmRnzoHGavKVHwYvao07jNN+V99LPq7OLvku5ZwantST W2tHVHorgwtJ+t1t2gMy7aXQG9KofVgnFmJJktOGbf2Rg9U34gptTGpHcFW4QrSdAIZa 0jC7MCAP/+DuhKX2YH/eWTxAVfOPOPwk6LnaiP3r5MD9V/SKb1gshEZ+vv9Ysu5aeXlB JLVA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=Dbgij4KdCuUgIto/9QTZly2/sdw9SHJOJXzPvbzOwA0=; b=jXFKxXmMi4buu+OR7NP+9CuC1iBzCZS85Dg9VNjFrwiVA2tWfWzIlpFBuBveTvybe5 XHj/MFIW84WkjMNQJ4AlEi5qxhDXlSskU6FKqp10e/O09ouadvH2DFFWKh3hE89vkpeo 9Uy91Bq8qe/n2n6F4p3cR+wdkSGpFagGr6MD7W0eGgOtkKY7eVY7Uf5eNY/Al+VqORLr JZYNLL8QT3lQh16ZX80iD/OsRppLIhbL7xFS6dz9p5uviJiaUEgauWSLDyiPxnvArJP3 chd0aiUMZaVePZHPGzbk99cYQnjlUdwqgANZzJVasP27o924ViIgbo+zHuaiovGeF9fd 0IhQ== X-Gm-Message-State: ACrzQf11f/Hr/BL4JqFF9ZUIeZR4t1QkOJrKV8pw48BkDF9bZRSRNsOK KMWiQHy+CnltFD6x1f9EgkE= X-Google-Smtp-Source: AMsMyM5T1SB+SiekgWPLqAopHmHeNbObB4Cruq1OCGKO9x5y5hm55FkE//h8CVaFPe2nPzlrgzByLQ== X-Received: by 2002:a05:6000:1561:b0:22e:6c59:e347 with SMTP id 1-20020a056000156100b0022e6c59e347mr12033097wrz.519.1666348576869; Fri, 21 Oct 2022 03:36:16 -0700 (PDT) Received: from 127.0.0.1localhost.com ([2620:10d:c092:600::2:f27e]) by smtp.gmail.com with ESMTPSA id e14-20020a5d65ce000000b0022abcc1e3cesm18544759wrw.116.2022.10.21.03.36.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 21 Oct 2022 03:36:16 -0700 (PDT) From: Pavel Begunkov To: Jens Axboe , linux-block@vger.kernel.org Cc: io-uring@vger.kernel.org, linux-kernel@vger.kernel.org, Christoph Hellwig , Pavel Begunkov Subject: [PATCH for-next v3 2/3] block/bio: add pcpu caching for non-polling bio_put Date: Fri, 21 Oct 2022 11:34:06 +0100 Message-Id: <4bf4e1716600b929866c13b4c15dcf94f11f9f3f.1666347703.git.asml.silence@gmail.com> X-Mailer: git-send-email 2.38.0 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org This patch extends REQ_ALLOC_CACHE to IRQ completions, whenever currently it's only limited to iopoll. Instead of guarding the list with irq toggling on alloc, which is expensive, it keeps an additional irq-safe list from which bios are spliced in batches to ammortise overhead. On the put side it toggles irqs, but in many cases they're already disabled and so cheap. Signed-off-by: Pavel Begunkov --- block/bio.c | 63 +++++++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 51 insertions(+), 12 deletions(-) diff --git a/block/bio.c b/block/bio.c index 7a573e0f5f52..f7c57352f306 100644 --- a/block/bio.c +++ b/block/bio.c @@ -25,9 +25,15 @@ #include "blk-rq-qos.h" #include "blk-cgroup.h" +#define ALLOC_CACHE_THRESHOLD 16 +#define ALLOC_CACHE_SLACK 64 +#define ALLOC_CACHE_MAX 512 + struct bio_alloc_cache { struct bio *free_list; + struct bio *free_list_irq; unsigned int nr; + unsigned int nr_irq; }; static struct biovec_slab { @@ -408,6 +414,22 @@ static void punt_bios_to_rescuer(struct bio_set *bs) queue_work(bs->rescue_workqueue, &bs->rescue_work); } +static void bio_alloc_irq_cache_splice(struct bio_alloc_cache *cache) +{ + unsigned long flags; + + /* cache->free_list must be empty */ + if (WARN_ON_ONCE(cache->free_list)) + return; + + local_irq_save(flags); + cache->free_list = cache->free_list_irq; + cache->free_list_irq = NULL; + cache->nr += cache->nr_irq; + cache->nr_irq = 0; + local_irq_restore(flags); +} + static struct bio *bio_alloc_percpu_cache(struct block_device *bdev, unsigned short nr_vecs, blk_opf_t opf, gfp_t gfp, struct bio_set *bs) @@ -416,9 +438,13 @@ static struct bio *bio_alloc_percpu_cache(struct block_device *bdev, struct bio *bio; cache = per_cpu_ptr(bs->cache, get_cpu()); - if (!cache->free_list) { - put_cpu(); - return NULL; + if (!cache->free_list && + READ_ONCE(cache->nr_irq) >= ALLOC_CACHE_THRESHOLD) { + bio_alloc_irq_cache_splice(cache); + if (!cache->free_list) { + put_cpu(); + return NULL; + } } bio = cache->free_list; cache->free_list = bio->bi_next; @@ -676,11 +702,8 @@ void guard_bio_eod(struct bio *bio) bio_truncate(bio, maxsector << 9); } -#define ALLOC_CACHE_MAX 512 -#define ALLOC_CACHE_SLACK 64 - -static void bio_alloc_cache_prune(struct bio_alloc_cache *cache, - unsigned int nr) +static int __bio_alloc_cache_prune(struct bio_alloc_cache *cache, + unsigned int nr) { unsigned int i = 0; struct bio *bio; @@ -692,6 +715,17 @@ static void bio_alloc_cache_prune(struct bio_alloc_cache *cache, if (++i == nr) break; } + return i; +} + +static void bio_alloc_cache_prune(struct bio_alloc_cache *cache, + unsigned int nr) +{ + nr -= __bio_alloc_cache_prune(cache, nr); + if (!READ_ONCE(cache->free_list)) { + bio_alloc_irq_cache_splice(cache); + __bio_alloc_cache_prune(cache, nr); + } } static int bio_cpu_dead(unsigned int cpu, struct hlist_node *node) @@ -737,12 +771,17 @@ static inline void bio_put_percpu_cache(struct bio *bio) cache->free_list = bio; cache->nr++; } else { - put_cpu(); - bio_free(bio); - return; + unsigned long flags; + + local_irq_save(flags); + bio->bi_next = cache->free_list_irq; + cache->free_list_irq = bio; + cache->nr_irq++; + local_irq_restore(flags); } - if (cache->nr > ALLOC_CACHE_MAX + ALLOC_CACHE_SLACK) + if (READ_ONCE(cache->nr_irq) + cache->nr > + ALLOC_CACHE_MAX + ALLOC_CACHE_SLACK) bio_alloc_cache_prune(cache, ALLOC_CACHE_SLACK); put_cpu(); }