From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta0.migadu.com (out-220.mta0.migadu.com [91.218.175.220]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3367E33C19E for ; Tue, 8 Sep 2026 02:22:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.220 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788834127; cv=none; b=fA0uEwFoUIwLb9vbf+5+YHTps4lz9QWvwgDerNSwOgs9DxnX/eIqQHq3W490tEJanOaWpbpTh8LF0nbKe3ENZARMc3e6H4tApBPKjrzZI+SNLkf0g9lamKwJ+n8tJ5bnUB6Xq/KHFvokAuIB0oDa7oq5eFQhKEGcYXK+AlLAiUg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788834127; c=relaxed/simple; bh=RlLZG9DF6LMhq752V92mo173s8ccnTQNr43ipFQvvoo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Cyn0VOZbQOWKgCRlplDzpfVdZffeDFoGRIuFWBBzMhRVwCt2CdBNR38JtHpH6NCsNp7McFs0A9+k3EAZVW1M5CWaRW9mbjxZeWlX++GHerojr5oAi9HYDCaLa+Hkq9VSPLY0bzd6EexVSfNuimeRpIUFU5yRr9Ls8oDaci3Snns= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=MoRFccNJ; arc=none smtp.client-ip=91.218.175.220 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="MoRFccNJ" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=RlLZG9DF6LMhq752V92mo173s8ccnTQNr43ipFQvvoo=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1788834124; v=1; x=1789438924; b=MoRFccNJtw9FXGRQz2iJn/dFpgWkGqRUnSvMH86oAAG/7sX6gKiw0mPCYH2wTuyiH8NEQSpJ wp8kJri79LhY1tJJHWJ46XXIaGZ/XO/moyHnUmsddYMKW5pjMr4AxeN8R45FxKZo2G7oYa1KwcO HvgFtH9oDQuArD060ng5N36w= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 6471dc207b4861e7; Tue, 08 Sep 2026 02:22:04 +0000 X-Mizu-Trace-ID: 6471dc207b4861e7 X-Migadu-Flow: FLOW_OUT From: Tao Cui To: tj@kernel.org, josef@toxicopanda.com, axboe@kernel.dk Cc: cgroups@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, cui.tao@linux.dev, Tao Cui Subject: [PATCH 2/4] blk-iocost: charge zone appends as page-counted sequential writes Date: Tue, 8 Sep 2026 10:21:33 +0800 Message-ID: <20260908022135.1429281-3-cui.tao@linux.dev> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260908022135.1429281-1-cui.tao@linux.dev> References: <20260908022135.1429281-1-cui.tao@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Tao Cui Zone append is a primary write operation for zoned devices; zoned btrfs and f2fs use it for data writes. It is priced at zero, so the zone append portion of zoned workloads runs outside the controller: a 1%-weight cgroup issued 16000 appends at zero cost on a zoned null_blk. A zone append advances the zone write pointer and is therefore sequential from the device's perspective; the actual sector is only returned after completion, so the cursor-based seq/rand classification doesn't apply. Price it as a page-counted sequential write. After this patch, 16000 appends from the same cgroup are charged 533264 usec (33us per append). Also skip the cursor update for ZA bios: bi_sector is the zone start, not the actual write position (which is only returned after completion). Setting the cursor from ZA would misclassify subsequent READ/WRITE bios. Fixes: 7caa47151ab2 ("blkcg: implement blk-iocost") Signed-off-by: Tao Cui --- block/blk-iocost.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/block/blk-iocost.c b/block/blk-iocost.c index abc512532ed9..d7860ec1ad49 100644 --- a/block/blk-iocost.c +++ b/block/blk-iocost.c @@ -2557,6 +2557,17 @@ static void calc_vtime_cost_builtin(struct bio *bio, struct ioc_gq *iocg, coef_randio = ioc->params.lcoefs[LCOEF_WRANDIO]; coef_page = ioc->params.lcoefs[LCOEF_WPAGE]; break; + case REQ_OP_ZONE_APPEND: + /* + * A zone append advances the zone write pointer and is + * therefore sequential from the device's perspective, so + * the cursor-based classification below doesn't apply. + * Compute the full cost here. + */ + if (!is_merge) + cost += ioc->params.lcoefs[LCOEF_WSEQIO]; + cost += pages * ioc->params.lcoefs[LCOEF_WPAGE]; + goto out; default: goto out; } @@ -2717,7 +2728,9 @@ static void ioc_rqos_throttle(struct rq_qos *rqos, struct bio *bio) if (!iocg_activate(iocg, &now)) return; - iocg->cursor = bio_end_sector(bio); + /* ZA bi_sector is zone start, not the write position */ + if (bio_op(bio) != REQ_OP_ZONE_APPEND) + iocg->cursor = bio_end_sector(bio); vtime = atomic64_read(&iocg->vtime); cost = adjust_inuse_and_calc_cost(iocg, vtime, abs_cost, &now); -- 2.43.0