From patchwork Thu Mar 9 21:54:53 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Niklas Cassel X-Patchwork-Id: 661480 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 BA922C6FD19 for ; Thu, 9 Mar 2023 21:55:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230044AbjCIVzc (ORCPT ); Thu, 9 Mar 2023 16:55:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50036 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229827AbjCIVz3 (ORCPT ); Thu, 9 Mar 2023 16:55:29 -0500 Received: from esa6.hgst.iphmx.com (esa6.hgst.iphmx.com [216.71.154.45]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 54567EFF56; Thu, 9 Mar 2023 13:55:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=wdc.com; i=@wdc.com; q=dns/txt; s=dkim.wdc.com; t=1678398928; x=1709934928; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=1Zry+xIqYFsz3JgSeEtU4aVUlj69W599ZfDPhMsvGkY=; b=T5DqoNQO6N0J3w5XNU8/wbHyheUzl4DroKizwfptYVpGoE+Y3TeFZoJj nX2Gfov8no7mEXJy8O+13jBFF4mPWbfD87gKlB+qu2kGmu+vkS0Rr2TO5 NuW5l27PPgcSGSwcwuds9Oiuv4+vXdIqWYF84TCP+cYEoa2Z8bIZyw4Na ER9t7APGg+VGYHgfHmPW1xgaeYwozAugp3ysuQeV48idTDd+05xAlUvRm 4K9G+jnWuJiwq0suAHYyogNgCUnuBaO9VNgdt/+Soov0PfeOeiXmWNqSN w1mOEjGKrjtmR+Zj5Lr9lFG73o80QKs7rRKDqY1cYOzOXyvbgDLsU5gKi A==; X-IronPort-AV: E=Sophos;i="5.98,247,1673884800"; d="scan'208";a="225270940" Received: from h199-255-45-15.hgst.com (HELO uls-op-cesaep02.wdc.com) ([199.255.45.15]) by ob1.hgst.iphmx.com with ESMTP; 10 Mar 2023 05:55:28 +0800 IronPort-SDR: VVbJiTIdM9vIQ/kK+wllKsZ/y5gh1stwbdcSWWMsTK+dHdLeY4Tpt33hXiDPY/JP28671q1IZr tNcD1wReMO2kXUo23TanelEX+9faG4ae6BOGNkED9K98ZaYt9qiUJ/PWGjhD3CQg612nfgFivb HkRBS4n4jlzpEARvP7GvpvLb4g+iH0qKAOqJlrn89LyrG8O3cGJj62iFpcmx5WHONlus0Bg3G7 OFvHI/GfXAWBUfKBqIPTnapkqY2B/PbbypaTqzILEfUTGGK1clqA4dl9QlY2afVBAW+4wEyr7d 8yk= Received: from uls-op-cesaip01.wdc.com ([10.248.3.36]) by uls-op-cesaep02.wdc.com with ESMTP/TLS/ECDHE-RSA-AES128-GCM-SHA256; 09 Mar 2023 13:06:21 -0800 IronPort-SDR: Jjcbd6yG/XIPTYDwnd/aqeqqms583YFh60V6QSRq8tsGNVFDgbyRhAdVhp7peXPfsFvO9pW4fA wAb0PUZaQSd5W9R6+b5u3xA9mbtDdjtYTFqHzJC7jBzpHpAfb7kbmNZsAZDYNaGhoyUMLqHMao kgWy2FJbxIeJO19ZkG/MHEoL3Mctij0fw6WgimsCyDGcXXNoOa44e3ky2uOLxvEktqQhMIyLks B/DjA+cKAowfk5VMGgdE0qLi72WCWqnc13eFPPFPlUrJvBUg7b28T8rrK30A9WxY0pSJr59YOO EG0= WDCIronportException: Internal Received: from unknown (HELO x1-carbon.wdc.com) ([10.225.164.41]) by uls-op-cesaip01.wdc.com with ESMTP; 09 Mar 2023 13:55:26 -0800 From: Niklas Cassel To: Paolo Valente , Jens Axboe Cc: Christoph Hellwig , Hannes Reinecke , Damien Le Moal , linux-scsi@vger.kernel.org, linux-ide@vger.kernel.org, linux-block@vger.kernel.org, Niklas Cassel Subject: [PATCH v4 01/19] ioprio: cleanup interface definition Date: Thu, 9 Mar 2023 22:54:53 +0100 Message-Id: <20230309215516.3800571-2-niklas.cassel@wdc.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230309215516.3800571-1-niklas.cassel@wdc.com> References: <20230309215516.3800571-1-niklas.cassel@wdc.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org From: Damien Le Moal The IO priority user interface defines the 16-bits ioprio values as the combination of the upper 3-bits for an IO priority class and the lower 13-bits as priority data. However, the kernel only uses the lower 3-bits of the priority data to define priority levels for the RT and BE priority classes. The data part of an ioprio value is completely ignored for the IDLE and NONE classes. This is enforced by checks done in ioprio_check_cap(), which is called for all paths that allow defining an IO priority for IOs: the per-context ioprio_set() system call, aio interface and io-uring interface. Clarify this fact in the uapi ioprio.h header file and introduce the IOPRIO_PRIO_LEVEL_MASK and IOPRIO_PRIO_LEVEL() macros for users to define and get priority levels in an ioprio value. The coarser macro IOPRIO_PRIO_DATA() is retained for backward compatibility with old applications already using it. There is no functional change introduced with this. In-kernel users of the IOPRIO_PRIO_DATA() macro which are explicitly handling IO priority data as a priority level are modified to use the new IOPRIO_PRIO_LEVEL() macro without any functional change. Since f2fs is the only user of this macro not explicitly using that value as a priority level, it is left unchanged. Signed-off-by: Damien Le Moal Signed-off-by: Niklas Cassel --- block/bfq-iosched.c | 8 ++++---- block/ioprio.c | 6 +++--- include/uapi/linux/ioprio.h | 19 ++++++++++++++----- 3 files changed, 21 insertions(+), 12 deletions(-) diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 8a8d4441519c..e4ca0a3483d3 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -5523,16 +5523,16 @@ bfq_set_next_ioprio_data(struct bfq_queue *bfqq, struct bfq_io_cq *bic) bfqq->new_ioprio_class = task_nice_ioclass(tsk); break; case IOPRIO_CLASS_RT: - bfqq->new_ioprio = IOPRIO_PRIO_DATA(bic->ioprio); + bfqq->new_ioprio = IOPRIO_PRIO_LEVEL(bic->ioprio); bfqq->new_ioprio_class = IOPRIO_CLASS_RT; break; case IOPRIO_CLASS_BE: - bfqq->new_ioprio = IOPRIO_PRIO_DATA(bic->ioprio); + bfqq->new_ioprio = IOPRIO_PRIO_LEVEL(bic->ioprio); bfqq->new_ioprio_class = IOPRIO_CLASS_BE; break; case IOPRIO_CLASS_IDLE: bfqq->new_ioprio_class = IOPRIO_CLASS_IDLE; - bfqq->new_ioprio = 7; + bfqq->new_ioprio = IOPRIO_NR_LEVELS - 1; break; } @@ -5829,7 +5829,7 @@ static struct bfq_queue *bfq_get_queue(struct bfq_data *bfqd, struct bfq_io_cq *bic, bool respawn) { - const int ioprio = IOPRIO_PRIO_DATA(bic->ioprio); + const int ioprio = IOPRIO_PRIO_LEVEL(bic->ioprio); const int ioprio_class = IOPRIO_PRIO_CLASS(bic->ioprio); struct bfq_queue **async_bfqq = NULL; struct bfq_queue *bfqq; diff --git a/block/ioprio.c b/block/ioprio.c index 32a456b45804..f0d9e818abc5 100644 --- a/block/ioprio.c +++ b/block/ioprio.c @@ -33,7 +33,7 @@ int ioprio_check_cap(int ioprio) { int class = IOPRIO_PRIO_CLASS(ioprio); - int data = IOPRIO_PRIO_DATA(ioprio); + int level = IOPRIO_PRIO_LEVEL(ioprio); switch (class) { case IOPRIO_CLASS_RT: @@ -49,13 +49,13 @@ int ioprio_check_cap(int ioprio) fallthrough; /* rt has prio field too */ case IOPRIO_CLASS_BE: - if (data >= IOPRIO_NR_LEVELS || data < 0) + if (level >= IOPRIO_NR_LEVELS) return -EINVAL; break; case IOPRIO_CLASS_IDLE: break; case IOPRIO_CLASS_NONE: - if (data) + if (level) return -EINVAL; break; default: diff --git a/include/uapi/linux/ioprio.h b/include/uapi/linux/ioprio.h index f70f2596a6bf..4444b4e4fdad 100644 --- a/include/uapi/linux/ioprio.h +++ b/include/uapi/linux/ioprio.h @@ -17,7 +17,7 @@ ((data) & IOPRIO_PRIO_MASK)) /* - * These are the io priority groups as implemented by the BFQ and mq-deadline + * These are the io priority classes as implemented by the BFQ and mq-deadline * schedulers. RT is the realtime class, it always gets premium service. For * ATA disks supporting NCQ IO priority, RT class IOs will be processed using * high priority NCQ commands. BE is the best-effort scheduling class, the @@ -32,11 +32,20 @@ enum { }; /* - * The RT and BE priority classes both support up to 8 priority levels. + * The RT and BE priority classes both support up to 8 priority levels that + * can be specified using the lower 3-bits of the priority data. */ -#define IOPRIO_NR_LEVELS 8 -#define IOPRIO_BE_NR IOPRIO_NR_LEVELS +#define IOPRIO_LEVEL_NR_BITS 3 +#define IOPRIO_NR_LEVELS (1 << IOPRIO_LEVEL_NR_BITS) +#define IOPRIO_LEVEL_MASK (IOPRIO_NR_LEVELS - 1) +#define IOPRIO_PRIO_LEVEL(ioprio) ((ioprio) & IOPRIO_LEVEL_MASK) +#define IOPRIO_BE_NR IOPRIO_NR_LEVELS + +/* + * Possible values for the "which" argument of the ioprio_get() and + * ioprio_set() system calls (see "man ioprio_set"). + */ enum { IOPRIO_WHO_PROCESS = 1, IOPRIO_WHO_PGRP, @@ -44,7 +53,7 @@ enum { }; /* - * Fallback BE priority level. + * Fallback BE class priority level. */ #define IOPRIO_NORM 4 #define IOPRIO_BE_NORM IOPRIO_NORM