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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id F1E40C4332F for ; Wed, 23 Nov 2022 06:04:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235913AbiKWGEj (ORCPT ); Wed, 23 Nov 2022 01:04:39 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42616 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235620AbiKWGEK (ORCPT ); Wed, 23 Nov 2022 01:04:10 -0500 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9F3BB729A9; Tue, 22 Nov 2022 22:04:08 -0800 (PST) Received: from kwepemi500016.china.huawei.com (unknown [172.30.72.53]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4NH9Tv0SYGzJnrQ; Wed, 23 Nov 2022 14:00:51 +0800 (CST) Received: from huawei.com (10.174.178.129) by kwepemi500016.china.huawei.com (7.221.188.220) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Wed, 23 Nov 2022 14:04:06 +0800 From: Kemeng Shi To: , , CC: , , , Subject: [PATCH 04/11] blk-throttle: correct calculation of wait time in tg_may_dispatch Date: Wed, 23 Nov 2022 14:03:54 +0800 Message-ID: <20221123060401.20392-5-shikemeng@huawei.com> X-Mailer: git-send-email 2.14.1.windows.1 In-Reply-To: <20221123060401.20392-1-shikemeng@huawei.com> References: <20221123060401.20392-1-shikemeng@huawei.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.174.178.129] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To kwepemi500016.china.huawei.com (7.221.188.220) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If bps and iops both reach limit, we always return bps wait time as tg_within_iops_limit is after "tg_within_bps_limit(tg, bio, bps_limit) &&" and will not be called if tg_within_bps_limit return true. Fix this by always calling tg_within_bps_limit and tg_within_iops_limit to get wait time for both bps and iops. Observed that: 1. Wait time in tg_within_iops_limit/tg_within_bps_limit need always be stored as wait argument is always passed. 2. Stored wait time is zero if iops/bps is limited otherwise non-zero is stored. Simpfy tg_within_iops_limit/tg_within_bps_limit by removing wait argument and return wait time directly. Caller tg_may_dispatch checks if wait time is zero to find if iops/bps is limited. Signed-off-by: Kemeng Shi --- block/blk-throttle.c | 38 +++++++++++++------------------------- 1 file changed, 13 insertions(+), 25 deletions(-) diff --git a/block/blk-throttle.c b/block/blk-throttle.c index acfac916ed99..01e30380c19b 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -815,17 +815,15 @@ static void tg_update_carryover(struct throtl_grp *tg) tg->carryover_ios[READ], tg->carryover_ios[WRITE]); } -static bool tg_within_iops_limit(struct throtl_grp *tg, struct bio *bio, - u32 iops_limit, unsigned long *wait) +static unsigned long tg_within_iops_limit(struct throtl_grp *tg, struct bio *bio, + u32 iops_limit) { bool rw = bio_data_dir(bio); unsigned int io_allowed; unsigned long jiffy_elapsed, jiffy_wait, jiffy_elapsed_rnd; if (iops_limit == UINT_MAX) { - if (wait) - *wait = 0; - return true; + return 0; } jiffy_elapsed = jiffies - tg->slice_start[rw]; @@ -835,21 +833,16 @@ static bool tg_within_iops_limit(struct throtl_grp *tg, struct bio *bio, io_allowed = calculate_io_allowed(iops_limit, jiffy_elapsed_rnd) + tg->carryover_ios[rw]; if (tg->io_disp[rw] + 1 <= io_allowed) { - if (wait) - *wait = 0; - return true; + return 0; } /* Calc approx time to dispatch */ jiffy_wait = jiffy_elapsed_rnd - jiffy_elapsed; - - if (wait) - *wait = jiffy_wait; - return false; + return jiffy_wait; } -static bool tg_within_bps_limit(struct throtl_grp *tg, struct bio *bio, - u64 bps_limit, unsigned long *wait) +static unsigned long tg_within_bps_limit(struct throtl_grp *tg, struct bio *bio, + u64 bps_limit) { bool rw = bio_data_dir(bio); u64 bytes_allowed, extra_bytes; @@ -857,9 +850,7 @@ static bool tg_within_bps_limit(struct throtl_grp *tg, struct bio *bio, unsigned int bio_size = throtl_bio_data_size(bio); if (bps_limit == U64_MAX) { - if (wait) - *wait = 0; - return true; + return 0; } jiffy_elapsed = jiffy_elapsed_rnd = jiffies - tg->slice_start[rw]; @@ -872,9 +863,7 @@ static bool tg_within_bps_limit(struct throtl_grp *tg, struct bio *bio, bytes_allowed = calculate_bytes_allowed(bps_limit, jiffy_elapsed_rnd) + tg->carryover_bytes[rw]; if (tg->bytes_disp[rw] + bio_size <= bytes_allowed) { - if (wait) - *wait = 0; - return true; + return 0; } /* Calc approx time to dispatch */ @@ -889,9 +878,7 @@ static bool tg_within_bps_limit(struct throtl_grp *tg, struct bio *bio, * up we did. Add that time also. */ jiffy_wait = jiffy_wait + (jiffy_elapsed_rnd - jiffy_elapsed); - if (wait) - *wait = jiffy_wait; - return false; + return jiffy_wait; } /* @@ -939,8 +926,9 @@ static bool tg_may_dispatch(struct throtl_grp *tg, struct bio *bio, jiffies + tg->td->throtl_slice); } - if (tg_within_bps_limit(tg, bio, bps_limit, &bps_wait) && - tg_within_iops_limit(tg, bio, iops_limit, &iops_wait)) { + bps_wait = tg_within_bps_limit(tg, bio, bps_limit); + iops_wait = tg_within_iops_limit(tg, bio, iops_limit); + if (bps_wait + iops_wait == 0) { if (wait) *wait = 0; return true; -- 2.30.0