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 E3CD0C46467 for ; Wed, 11 Jan 2023 16:07:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232062AbjAKQHx (ORCPT ); Wed, 11 Jan 2023 11:07:53 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49666 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235042AbjAKQHi (ORCPT ); Wed, 11 Jan 2023 11:07:38 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 113C211C28 for ; Wed, 11 Jan 2023 08:06:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1673453180; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=z1BOT8mAy+WkQiTgOjzQ2w9X/QEdQS1JO0z90YIXXdk=; b=cDoiBSsplnzCWus0fZOZ68NGGZvAfguGl6Bg/QQKn7H3ksSegp00xKlhFSJvvVt658dTUt FVMomz7dHKzjcjoCoCxmfPBszuj800s+mO+wLQOfqMBqAxUrIPC+HYhS81XvKCAq8piZuK nENRZ1vy0hwpmcbHezXihvp7mqjwu/I= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-259-3UZB8fl6PHyrfmyEvQ-2PA-1; Wed, 11 Jan 2023 11:06:14 -0500 X-MC-Unique: 3UZB8fl6PHyrfmyEvQ-2PA-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id CD98F1C29D43; Wed, 11 Jan 2023 16:06:13 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.33.36.87]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5A4AEC15BA0; Wed, 11 Jan 2023 16:06:11 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <20221226103309.953112-2-houtao@huaweicloud.com> References: <20221226103309.953112-2-houtao@huaweicloud.com> <20221226103309.953112-1-houtao@huaweicloud.com> To: Hou Tao Cc: dhowells@redhat.com, linux-cachefs@redhat.com, Jeff Layton , linux-erofs@lists.ozlabs.org, linux-kernel@vger.kernel.org, Jingbo Xu , houtao1@huawei.com Subject: Re: [PATCH v2 1/2] fscache: Use wait_on_bit() to wait for the freeing of relinquished volume MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <2431837.1673453170.1@warthog.procyon.org.uk> Date: Wed, 11 Jan 2023 16:06:10 +0000 Message-ID: <2431838.1673453170@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.8 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hou Tao wrote: > clear_bit(FSCACHE_VOLUME_ACQUIRE_PENDING, &cursor->flags); > + /* > + * Paired with barrier in wait_on_bit(). Check > + * wake_up_bit() and waitqueue_active() for details. > + */ > + smp_mb__after_atomic(); > wake_up_bit(&cursor->flags, FSCACHE_VOLUME_ACQUIRE_PENDING); What two values are you applying a partial ordering to? David