From patchwork Fri Apr 21 02:50:38 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tejun Heo X-Patchwork-Id: 13219407 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 1F813C77B73 for ; Fri, 21 Apr 2023 02:51:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233949AbjDUCvz (ORCPT ); Thu, 20 Apr 2023 22:51:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43512 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233767AbjDUCvS (ORCPT ); Thu, 20 Apr 2023 22:51:18 -0400 Received: from mail-pl1-x62a.google.com (mail-pl1-x62a.google.com [IPv6:2607:f8b0:4864:20::62a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 65F057292; Thu, 20 Apr 2023 19:51:17 -0700 (PDT) Received: by mail-pl1-x62a.google.com with SMTP id d9443c01a7336-1a92513abebso19694875ad.2; Thu, 20 Apr 2023 19:51:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1682045477; x=1684637477; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:sender:from:to:cc:subject:date :message-id:reply-to; bh=dorQ2qlHIQqiNBUoiQdfsVbgm5wQDWFtkN4YHEiGiW0=; b=qcJ3g04qdI5nJnF0RwVis4v7EzX0fPL613I0miXb8OBRVtnPZi9rsPKFiOjvtxzM9D k4Lc3kzcMkqM07Gz7lPfr65+OH1ShvUvlu3vKZQ0fksXbAXYpykFjcdCl1ksoIWsEFYw rlrADdfGdmznF4OYk1+zclIZmpe23JU/7PO2So1p+ZwS90tZHUeLdizz1m7pulXEmZhP JGKQXVuxT0LKxJS228sfpj/zMqKIox+ydHEQeloOIjfeqjSuZ8kOkXhW9pxOklPjfL00 93syjdjXSPpvWDcKqeuDfLzjyTy/SCOqiAy9ukPDb2LF4fKF1DQoMLXT/IpOgRa9GTEE ZPkg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1682045477; x=1684637477; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:sender:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=dorQ2qlHIQqiNBUoiQdfsVbgm5wQDWFtkN4YHEiGiW0=; b=Z1AzSHRfN+nxvvhvI5oyr2CNGwfYyBndxOq7C9SVHs5YalzuNgEjTTUGHFFn5aFMQb F4iIKSLvBJ6dzDc8D7G7th0Ue+kTOEwxu10WMObZfaRN6SewWIxtnXtc65HqQZiCiBHM P9/VvrhzIR2AoK8E/2xdU/b3Jt6IA834RDdvJNJurfkp8p62tU6K7KZ28aH+9EJdq+5x mMgzX1pqtWVLsR0HTvh5/J1frGjoJAx49kF7s5bKvemcNehNyobwwMlK4XY5Q8tUzloH /FqTAXBW1WfvUs/lCkRM+Wkqy6N0CHvz2IrNvsUuGnOW8dBK9flCdN8I6whkOTdBQ2T/ ypJw== X-Gm-Message-State: AAQBX9cIRvImqgRtXtcU+8SMJq1857xxBswCuoWNn2J/T0yZOVHBMz13 kEY2a+8HpRuuNAFdVEhKaX2+h+rUlTY= X-Google-Smtp-Source: AKy350brCnllqVIbTvbVAizAFvwU8LbM/ZVhCoz2xu5/RFCnO/Uyv0+3NE55K22qXrDnqJDgSkgCvg== X-Received: by 2002:a17:902:748c:b0:1a6:be37:22e1 with SMTP id h12-20020a170902748c00b001a6be3722e1mr3102959pll.15.1682045476738; Thu, 20 Apr 2023 19:51:16 -0700 (PDT) Received: from localhost (2603-800c-1a02-1bae-a7fa-157f-969a-4cde.res6.spectrum.com. [2603:800c:1a02:1bae:a7fa:157f:969a:4cde]) by smtp.gmail.com with ESMTPSA id k1-20020a170902760100b001a1adbe215asm1741130pll.142.2023.04.20.19.51.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 Apr 2023 19:51:16 -0700 (PDT) Sender: Tejun Heo From: Tejun Heo To: jiangshanlai@gmail.com Cc: linux-kernel@vger.kernel.org, kernel-team@meta.com, Tejun Heo , Andy Gross , Bjorn Andersson , Konrad Dybcio , linux-arm-msm@vger.kernel.org Subject: [PATCH 14/22] soc: qcom: qmi: Use alloc_ordered_workqueue() to create ordered workqueues Date: Thu, 20 Apr 2023 16:50:38 -1000 Message-Id: <20230421025046.4008499-15-tj@kernel.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230421025046.4008499-1-tj@kernel.org> References: <20230421025046.4008499-1-tj@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org BACKGROUND ========== When multiple work items are queued to a workqueue, their execution order doesn't match the queueing order. They may get executed in any order and simultaneously. When fully serialized execution - one by one in the queueing order - is needed, an ordered workqueue should be used which can be created with alloc_ordered_workqueue(). However, alloc_ordered_workqueue() was a later addition. Before it, an ordered workqueue could be obtained by creating an UNBOUND workqueue with @max_active==1. This originally was an implementation side-effect which was broken by 4c16bd327c74 ("workqueue: restore WQ_UNBOUND/max_active==1 to be ordered"). Because there were users that depended on the ordered execution, 5c0338c68706 ("workqueue: restore WQ_UNBOUND/max_active==1 to be ordered") made workqueue allocation path to implicitly promote UNBOUND workqueues w/ @max_active==1 to ordered workqueues. While this has worked okay, overloading the UNBOUND allocation interface this way creates other issues. It's difficult to tell whether a given workqueue actually needs to be ordered and users that legitimately want a min concurrency level wq unexpectedly gets an ordered one instead. With planned UNBOUND workqueue updates to improve execution locality and more prevalence of chiplet designs which can benefit from such improvements, this isn't a state we wanna be in forever. This patch series audits all callsites that create an UNBOUND workqueue w/ @max_active==1 and converts them to alloc_ordered_workqueue() as necessary. WHAT TO LOOK FOR ================ The conversions are from alloc_workqueue(WQ_UNBOUND | flags, 1, args..) to alloc_ordered_workqueue(flags, args...) which don't cause any functional changes. If you know that fully ordered execution is not ncessary, please let me know. I'll drop the conversion and instead add a comment noting the fact to reduce confusion while conversion is in progress. If you aren't fully sure, it's completely fine to let the conversion through. The behavior will stay exactly the same and we can always reconsider later. As there are follow-up workqueue core changes, I'd really appreciate if the patch can be routed through the workqueue tree w/ your acks. Thanks. Signed-off-by: Tejun Heo Cc: Andy Gross Cc: Bjorn Andersson Cc: Konrad Dybcio Cc: linux-arm-msm@vger.kernel.org --- drivers/soc/qcom/qmi_interface.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/soc/qcom/qmi_interface.c b/drivers/soc/qcom/qmi_interface.c index 820bdd9f8e46..78d7361fdcf2 100644 --- a/drivers/soc/qcom/qmi_interface.c +++ b/drivers/soc/qcom/qmi_interface.c @@ -650,7 +650,7 @@ int qmi_handle_init(struct qmi_handle *qmi, size_t recv_buf_size, if (!qmi->recv_buf) return -ENOMEM; - qmi->wq = alloc_workqueue("qmi_msg_handler", WQ_UNBOUND, 1); + qmi->wq = alloc_ordered_workqueue("qmi_msg_handler", 0); if (!qmi->wq) { ret = -ENOMEM; goto err_free_recv_buf; From patchwork Fri Apr 21 02:50:42 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tejun Heo X-Patchwork-Id: 13219408 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 48C76C77B73 for ; Fri, 21 Apr 2023 02:52:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234024AbjDUCwf (ORCPT ); Thu, 20 Apr 2023 22:52:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44200 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233869AbjDUCvq (ORCPT ); Thu, 20 Apr 2023 22:51:46 -0400 Received: from mail-pl1-x636.google.com (mail-pl1-x636.google.com [IPv6:2607:f8b0:4864:20::636]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C27507A9D; Thu, 20 Apr 2023 19:51:24 -0700 (PDT) Received: by mail-pl1-x636.google.com with SMTP id d9443c01a7336-1a66911f5faso15952255ad.0; Thu, 20 Apr 2023 19:51:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1682045484; x=1684637484; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:sender:from:to:cc:subject:date :message-id:reply-to; bh=mzGS+UdzXek+xJHu4+K3eBKPYOUbqdAU3uJzg+J1eL4=; b=poUS2eXvbKbyutb8Y/OZuu5rSs7SDpvdzJfbPtqCXkQr6zq/VoRNZSPZCmxBfUDsQP GkvMCSIZ3YzfPb7O9lTcuV1wf4zJPgioZ8kgl9goI5X6NIqHC37zHNuiWwN/Rm21qFIg +4Uu92wJQZjpsHFfV9M/FHgmiFGfRNM+dyDTQEGyshzxNKqs8CN5u3KNWKrLA20MKEMX oA39jTCD0hjwjpz6UvCFLWTy4p9590VZUhoKq4upOa+p17MccNMEUDRHX/+ZhgHYVbtX 18NdWSkK/S1DCFXwiAX6pxTUtLyTocrWQxuJkP22PyZW3ekvE+Xp0YUGFWTnnGrqfQ9O wt2w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1682045484; x=1684637484; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:sender:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=mzGS+UdzXek+xJHu4+K3eBKPYOUbqdAU3uJzg+J1eL4=; b=LxcZmpPaDpjNtJ2Dwpe1Pyr7mLLne7VOmBf9+Wg5gn5592a7y9l6r3LFnktz8RTeyH slqyhH3818sHNcwZV7/McT7/YNBjQcI8aNFqvYz4fa9qgZyuhBRn4ckYZ8t+ksrcYFI0 4KsofOCYCzqB0bg1AchlOoRUkLKlmgl1OTVHE4Bi1NxshziFdkIe8/mOCqXW/9vaaRTC skEFbxKI/0/GakPIocRLVPJWyoZe/NADU+badq962HwQ483LDKOAeB+oulv1RzN8XV3B rsHtV+RbqFqH2EZY6ksjbRbu2JSYqfKExNLUjlC1G8d9ZtF9QS9FZzTGqGdmhN7+cI5S YFyQ== X-Gm-Message-State: AAQBX9fKokeN39xEghey1MsrsbOqC1jrt8Jmt5SoHztMeszXrAUC737K YcFor45IalMPnbkvWqfL53eTmFL03FA= X-Google-Smtp-Source: AKy350adkbcdQ+ZlfSVaF6TDc/qHvNHFULbKey7nmI9cu4rWZjkWuS/PG4VbIJZp/FGuVePSV2tTUA== X-Received: by 2002:a17:902:f683:b0:1a8:17db:e252 with SMTP id l3-20020a170902f68300b001a817dbe252mr3875983plg.34.1682045483982; Thu, 20 Apr 2023 19:51:23 -0700 (PDT) Received: from localhost (2603-800c-1a02-1bae-a7fa-157f-969a-4cde.res6.spectrum.com. [2603:800c:1a02:1bae:a7fa:157f:969a:4cde]) by smtp.gmail.com with ESMTPSA id a13-20020a1709027d8d00b001a647709860sm1736293plm.157.2023.04.20.19.51.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 Apr 2023 19:51:23 -0700 (PDT) Sender: Tejun Heo From: Tejun Heo To: jiangshanlai@gmail.com Cc: linux-kernel@vger.kernel.org, kernel-team@meta.com, Tejun Heo , Manivannan Sadhasivam , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , linux-arm-msm@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH 18/22] net: qrtr: Use alloc_ordered_workqueue() to create ordered workqueues Date: Thu, 20 Apr 2023 16:50:42 -1000 Message-Id: <20230421025046.4008499-19-tj@kernel.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230421025046.4008499-1-tj@kernel.org> References: <20230421025046.4008499-1-tj@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org BACKGROUND ========== When multiple work items are queued to a workqueue, their execution order doesn't match the queueing order. They may get executed in any order and simultaneously. When fully serialized execution - one by one in the queueing order - is needed, an ordered workqueue should be used which can be created with alloc_ordered_workqueue(). However, alloc_ordered_workqueue() was a later addition. Before it, an ordered workqueue could be obtained by creating an UNBOUND workqueue with @max_active==1. This originally was an implementation side-effect which was broken by 4c16bd327c74 ("workqueue: restore WQ_UNBOUND/max_active==1 to be ordered"). Because there were users that depended on the ordered execution, 5c0338c68706 ("workqueue: restore WQ_UNBOUND/max_active==1 to be ordered") made workqueue allocation path to implicitly promote UNBOUND workqueues w/ @max_active==1 to ordered workqueues. While this has worked okay, overloading the UNBOUND allocation interface this way creates other issues. It's difficult to tell whether a given workqueue actually needs to be ordered and users that legitimately want a min concurrency level wq unexpectedly gets an ordered one instead. With planned UNBOUND workqueue updates to improve execution locality and more prevalence of chiplet designs which can benefit from such improvements, this isn't a state we wanna be in forever. This patch series audits all callsites that create an UNBOUND workqueue w/ @max_active==1 and converts them to alloc_ordered_workqueue() as necessary. WHAT TO LOOK FOR ================ The conversions are from alloc_workqueue(WQ_UNBOUND | flags, 1, args..) to alloc_ordered_workqueue(flags, args...) which don't cause any functional changes. If you know that fully ordered execution is not ncessary, please let me know. I'll drop the conversion and instead add a comment noting the fact to reduce confusion while conversion is in progress. If you aren't fully sure, it's completely fine to let the conversion through. The behavior will stay exactly the same and we can always reconsider later. As there are follow-up workqueue core changes, I'd really appreciate if the patch can be routed through the workqueue tree w/ your acks. Thanks. Signed-off-by: Tejun Heo Cc: Manivannan Sadhasivam Cc: "David S. Miller" Cc: Eric Dumazet Cc: Jakub Kicinski Cc: Paolo Abeni Cc: linux-arm-msm@vger.kernel.org Cc: netdev@vger.kernel.org --- net/qrtr/ns.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/qrtr/ns.c b/net/qrtr/ns.c index 0f25a386138c..0f7a729f1a1f 100644 --- a/net/qrtr/ns.c +++ b/net/qrtr/ns.c @@ -783,7 +783,7 @@ int qrtr_ns_init(void) goto err_sock; } - qrtr_ns.workqueue = alloc_workqueue("qrtr_ns_handler", WQ_UNBOUND, 1); + qrtr_ns.workqueue = alloc_ordered_workqueue("qrtr_ns_handler", 0); if (!qrtr_ns.workqueue) { ret = -ENOMEM; goto err_sock;