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[209.132.180.67]) by mx.google.com with ESMTP id c19si281187pfi.256.2019.07.12.20.53.27; Fri, 12 Jul 2019 20:53:43 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b="ZO/2nJnH"; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727655AbfGMDvm (ORCPT + 99 others); Fri, 12 Jul 2019 23:51:42 -0400 Received: from mail-qt1-f194.google.com ([209.85.160.194]:39110 "EHLO mail-qt1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727466AbfGMDvm (ORCPT ); Fri, 12 Jul 2019 23:51:42 -0400 Received: by mail-qt1-f194.google.com with SMTP id l9so10351508qtu.6; Fri, 12 Jul 2019 20:51:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=BIrfInZig2JFWZrOWBTKrHopPohB0GRCvYl01XlQKZc=; b=ZO/2nJnHNQ2qP7JqBYlDAInlXCZ42/Lr3cAJKTE93dAAc/YgOLRcmj3tDxyRcoEFTM nF0Y0r5lIq4pw5sa1jcqBPj2UPtRMCvUlwqD9P2XJ9HL+S1X8lahHheSUETAlHka3hoh cP+sSXgtayChoSFmJS8kBRUIUtQOqBG7CDDO6JN4YdQ1XD3HLlLOk/MVG8XXehMKMTsI zPZE1NJirzf/BWokbBh2V4uT1XX8ZX6H7zVrA9sOXNAwqTlIEm9epxwnU+Iqyucf+NMO BiFzeCG+qRzjQooz7Pkx5Q0VNsq9sMKjVw7XSDtxCtsf7AZ/kPTB8yPUW3VC6pPZUB84 dm2Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=BIrfInZig2JFWZrOWBTKrHopPohB0GRCvYl01XlQKZc=; b=GVQXOTtoZxCUQj8EBsKFejjBBdhSwDFGjJmdTQFO96KHXG4uj6MtE36zQrkxiahT9x vA4848B9Y0I3TMgXXx41AphxbpbLfi1P4j1csW1VKKx1F+qruaZpbvnviol0itEcT5sb +s+ZYV0kK80MWfANuN7HRVUI9YJXYa3Q/aDly83M/L9AkXBo/jdCWpdTE1xxUuvXmkmn gnMHXSrbtZ+0HhOrKe+uk+iTrLONZssMJSJWjZjC0nwHzm3tXnGXCzq9ge+3K0S+lPLW knsrudVQI0cJ2e440rKP/F7Jy/XPkC3YJAVZMiRqipKv5dqhCP3DIbfX1Ym8SZ12GCxs QlwQ== X-Gm-Message-State: APjAAAUHE+CV6r/fs9iXxA3EreXr1yjcYi12IZ6GzdtFpsWMKVI3IlSA iGPllAlDKNNtUorsGACheWme6Cq2IS8= X-Received: by 2002:ac8:40cc:: with SMTP id f12mr9063427qtm.256.1562989900733; Fri, 12 Jul 2019 20:51:40 -0700 (PDT) Received: from localhost.localdomain ([186.212.49.5]) by smtp.gmail.com with ESMTPSA id j2sm4823692qtb.89.2019.07.12.20.51.37 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Fri, 12 Jul 2019 20:51:39 -0700 (PDT) From: Marcos Paulo de Souza To: linux-kernel@vger.kernel.org Cc: Marcos Paulo de Souza , Jens Axboe , linux-block@vger.kernel.org (open list:BLOCK LAYER) Subject: [PATCH] block: elevator.c: Check elevator kernel argument again Date: Sat, 13 Jul 2019 00:52:21 -0300 Message-Id: <20190713035221.31508-1-marcos.souza.org@gmail.com> X-Mailer: git-send-email 2.22.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Since the inclusion of blk-mq, elevator= kernel argument was not being considered anymore, making it impossible to specify a specific elevator at boot time as it was used before. This is done by checking chosen_elevator global variable, which is populated once elevator= kernel argument is passed. Without this patch, mq-deadline is the only elevator that is can be used at boot time. Signed-off-by: Marcos Paulo de Souza --- I found this issue while inspecting why noop scheduler was gone, and so I found that was now impossible to use a scheduler different from mq-deadeline. Am I missing something? Is this a desirable behavior? One more question: currently we can't specify a "none" scheduler, like it used to be "noop". This is also on purpose? If it's not, I can provide a patch for it. block/elevator.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/block/elevator.c b/block/elevator.c index 2f17d66d0e61..41ce7ba099ba 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -601,7 +601,7 @@ int elevator_switch_mq(struct request_queue *q, */ int elevator_init_mq(struct request_queue *q) { - struct elevator_type *e; + struct elevator_type *e = NULL; int err = 0; if (q->nr_hw_queues != 1) @@ -615,9 +615,18 @@ int elevator_init_mq(struct request_queue *q) if (unlikely(q->elevator)) goto out_unlock; - e = elevator_get(q, "mq-deadline", false); - if (!e) - goto out_unlock; + /* if elevator was used as kernel argument, try to load it */ + if (*chosen_elevator) { + e = elevator_get(q, chosen_elevator, false); + if (!e) + pr_err("io scheduler %s not found", chosen_elevator); + } + + if (!e) { + e = elevator_get(q, "mq-deadline", false); + if (!e) + goto out_unlock; + } err = blk_mq_init_sched(q, e); if (err) -- 2.22.0