From patchwork Sat Apr 20 07:16:36 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Damien Le Moal X-Patchwork-Id: 13637046 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CAC8D12E6C for ; Sat, 20 Apr 2024 07:16:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713597399; cv=none; b=Yzgan6Z+KsrSw+bNOwYHxyD9DTpgQXFzXSi+mOyuRKKvmwFfFN4s+rmyuGd/dd3Xv3fz5xy4GCNcfN3eUcnupTCOng9jv/kjRjijCctxVkvxwr0ONLSakrCny9N7TEy1+FhQYbZRxlLBjntA0zFf0arqTIkqqjjHRNPI+3G0vuk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713597399; c=relaxed/simple; bh=oyiHc6p3G2ZI1v4mkmdMazewCoDvlhkyzs5XQlJyCrI=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=es+zjlJpEMy7ceKSNZ2F635PCC8fWxV00xrMKLDscsIouWwmi+6oWzgXUL/GAFUMJkDWSRR/N5vNBUJqpiCaJaSw5KmV7foMPgASJ6tmIVmlbpUhUAWvJ13a54V96IppWLHGK62Yl6FXyqWRNMHeV8jAddwzcFWAlwM1c6DmRMA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=QYgpHn3/; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="QYgpHn3/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1B824C3277B; Sat, 20 Apr 2024 07:16:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1713597399; bh=oyiHc6p3G2ZI1v4mkmdMazewCoDvlhkyzs5XQlJyCrI=; h=From:To:Subject:Date:In-Reply-To:References:From; b=QYgpHn3/bDPw9mN7GO64Mf0p1QNIPsH21ghsmU/9/Wuce7j0ZjiFv0OE53Y6sgSMs 9mVCNHGI+DevOa+gLM8hAXjsOOlBHAZhmfDEHTFQIWTLLtR+RhfFmIcu11YGDSOy+e D385JXdntChzllqjGfz7/oxrLVLO3hufOkJbYCmPTJhSGx9/PIjI7rEF/myxA8cXHX FACAY414am0Vo1qRGruhKx+0sPJlZhjKOOZ8+0bnG4AmufgsMo4JbpoWcLBwS/39wJ 2N5XHtKEnicqiW0nEIPMaa/FPS4ZRz04s4PI7AEVqAeHaQAzMNZ8z65eoS5PTUXAdB ISUNYbhiPWuDg== From: Damien Le Moal To: Jens Axboe , linux-block@vger.kernel.org Subject: [PATCH 1/2] block: prevent freeing a zone write plug too early Date: Sat, 20 Apr 2024 16:16:36 +0900 Message-ID: <20240420071637.1270724-2-dlemoal@kernel.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240420071637.1270724-1-dlemoal@kernel.org> References: <20240420071637.1270724-1-dlemoal@kernel.org> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 The submission of plugged BIOs is done using a work struct executing the function blk_zone_wplug_bio_work(). This function gets and submits a plugged zone write BIO and is guaranteed to operate on a valid zone write plug (with a reference count higher than 0) on entry as plugged BIOs hold a reference on their zone write plugs. However, once a BIO is submitted with submit_bio_noacct_nocheck(), the BIO may complete before blk_zone_wplug_bio_work(), with the BIO completion trigering a release and freeing of the zone write plug if the BIO is the last write to a zone (making the zone FULL). This potentially can result in the zone write plug being freed while the work is still active. Avoid this by calling flush_work() from disk_free_zone_wplug_rcu(). Fixes: dd291d77cc90 ("block: Introduce zone write plugging") Signed-off-by: Damien Le Moal --- block/blk-zoned.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/block/blk-zoned.c b/block/blk-zoned.c index 3befebe6b319..685f0b9159fd 100644 --- a/block/blk-zoned.c +++ b/block/blk-zoned.c @@ -526,6 +526,8 @@ static void disk_free_zone_wplug_rcu(struct rcu_head *rcu_head) struct blk_zone_wplug *zwplug = container_of(rcu_head, struct blk_zone_wplug, rcu_head); + flush_work(&zwplug->bio_work); + mempool_free(zwplug, zwplug->disk->zone_wplugs_pool); } From patchwork Sat Apr 20 07:16:37 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Damien Le Moal X-Patchwork-Id: 13637047 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8F8BE134BF for ; Sat, 20 Apr 2024 07:16:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713597400; cv=none; b=ZlmJY/zCXeN+l+5yktahYhi2L5mFzAETMw2/uzQHWqrD+xcaWYvvz8PTpLp1mPqS8r5mK+t4CHCPU7u4EnUjkx9cJvJX0D9PDAFZRZ7h1VY2UWwVx3F8KSbFaofYpjCSk7ue1afs7f0qVEUE5GZ31lBjyD3vV4g7QvFsPhwNQf8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713597400; c=relaxed/simple; bh=eSQtOIEoQ6lbva+vCRmGIHHLiyCrKZ+gQrQrpD5LHuY=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=QN9Uo2aPFyrujeizbZxEbtROc/cNnSef61bBCZMzrF4Rn6J/biHciDmJMXx/IFi2nQRMyWYgqg/0klHWrtSb25OIG/8f24MbRfMqOTPpWQjj4mCY61CAPML7d3V25Q9f3ew5T31AXPrqKdA95Xw7t2czXh51A3OrprPx5Ohl1n4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=izDIoGkK; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="izDIoGkK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C337DC113CE; Sat, 20 Apr 2024 07:16:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1713597400; bh=eSQtOIEoQ6lbva+vCRmGIHHLiyCrKZ+gQrQrpD5LHuY=; h=From:To:Subject:Date:In-Reply-To:References:From; b=izDIoGkK444Y7TnmLfRoK2kynsUCEnUmaS0W9AgCj+MRaZc3s6Mw9usGM5D/qTzsc WtEGoh8FgdZNy+JGdOHVPAyeVWGyEzUbU+rHrgaYCWZuhBzfqkiKFh2lwRxXg0ubW+ 88qHy4ZbMw15W+gWaTpO5iu2TdiSlTrhD951xGa8VHJGaXql2zMTDU6MoJaYYGvKKk edg33VsPX0cDq6v99PIQMyDRZfN8x7CAwolYnCns8FkQcIBoBnlUYD7yXfiEhdcygH MSnVSzZLASYNuW1DmpHaV8Q4RYztmnBbjNSWacuAl2gbZfkXVpNMiqyGf/iruGE7OX WrYg/DC13rTsQ== From: Damien Le Moal To: Jens Axboe , linux-block@vger.kernel.org Subject: [PATCH 2/2] block: use a per disk workqueue for zone write plugging Date: Sat, 20 Apr 2024 16:16:37 +0900 Message-ID: <20240420071637.1270724-3-dlemoal@kernel.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240420071637.1270724-1-dlemoal@kernel.org> References: <20240420071637.1270724-1-dlemoal@kernel.org> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 A zone write plug BIO work function blk_zone_wplug_bio_work() calls submit_bio_noacct_nocheck() to execute the next unplugged BIO. This function may block. So executing zone plugs BIO works using the block layer global kblockd workqueue can potentially lead to preformance or latency issues as the number of concurrent work for a workqueue is limited to WQ_DFL_ACTIVE (256). 1) For a system with a large number of zoned disks, issuing write requests to otherwise unused zones may be delayed wiating for a work thread to become available. 2) Requeue operations which use kblockd but are independent of zone write plugging may alsoi end up being delayed. To avoid these potential performance issues, create a workqueue per zoned device to execute zone plugs BIO work. The workqueue max active parameter is set to the maximum number of zone write plugs allocated with the zone write plug mempool. This limit is equal to the maximum number of open zones of the disk and defaults to 128 for disks that do not have a limit on the number of open zones. Fixes: dd291d77cc90 ("block: Introduce zone write plugging") Signed-off-by: Damien Le Moal --- block/blk-zoned.c | 32 ++++++++++++++++++++++++-------- include/linux/blkdev.h | 1 + 2 files changed, 25 insertions(+), 8 deletions(-) diff --git a/block/blk-zoned.c b/block/blk-zoned.c index 685f0b9159fd..9bed43472d43 100644 --- a/block/blk-zoned.c +++ b/block/blk-zoned.c @@ -1131,7 +1131,7 @@ static void disk_zone_wplug_unplug_bio(struct gendisk *disk, /* Schedule submission of the next plugged BIO if we have one. */ if (!bio_list_empty(&zwplug->bio_list)) { spin_unlock_irqrestore(&zwplug->lock, flags); - kblockd_schedule_work(&zwplug->bio_work); + queue_work(disk->zone_wplugs_wq, &zwplug->bio_work); return; } @@ -1334,7 +1334,7 @@ static void disk_zone_wplug_handle_error(struct gendisk *disk, /* Restart BIO submission if we still have any BIO left. */ if (!bio_list_empty(&zwplug->bio_list)) { WARN_ON_ONCE(!(zwplug->flags & BLK_ZONE_WPLUG_PLUGGED)); - kblockd_schedule_work(&zwplug->bio_work); + queue_work(disk->zone_wplugs_wq, &zwplug->bio_work); goto unlock; } @@ -1411,14 +1411,25 @@ static int disk_alloc_zone_resources(struct gendisk *disk, disk->zone_wplugs_pool = mempool_create_kmalloc_pool(pool_size, sizeof(struct blk_zone_wplug)); - if (!disk->zone_wplugs_pool) { - kfree(disk->zone_wplugs_hash); - disk->zone_wplugs_hash = NULL; - disk->zone_wplugs_hash_bits = 0; - return -ENOMEM; - } + if (!disk->zone_wplugs_pool) + goto free_hash; + + disk->zone_wplugs_wq = + alloc_workqueue("%s_zwplugs", WQ_MEM_RECLAIM | WQ_HIGHPRI, + 0, disk->disk_name); + if (!disk->zone_wplugs_wq) + goto destroy_pool; return 0; + +destroy_pool: + mempool_destroy(disk->zone_wplugs_pool); + disk->zone_wplugs_pool = NULL; +free_hash: + kfree(disk->zone_wplugs_hash); + disk->zone_wplugs_hash = NULL; + disk->zone_wplugs_hash_bits = 0; + return -ENOMEM; } static void disk_destroy_zone_wplugs_hash_table(struct gendisk *disk) @@ -1449,6 +1460,11 @@ void disk_free_zone_resources(struct gendisk *disk) { cancel_work_sync(&disk->zone_wplugs_work); + if (disk->zone_wplugs_wq) { + destroy_workqueue(disk->zone_wplugs_wq); + disk->zone_wplugs_wq = NULL; + } + disk_destroy_zone_wplugs_hash_table(disk); /* diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index c62536c78a46..a2847f8e5f82 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -191,6 +191,7 @@ struct gendisk { struct hlist_head *zone_wplugs_hash; struct list_head zone_wplugs_err_list; struct work_struct zone_wplugs_work; + struct workqueue_struct *zone_wplugs_wq; #endif /* CONFIG_BLK_DEV_ZONED */ #if IS_ENABLED(CONFIG_CDROM)