From patchwork Mon Aug 7 11:09:18 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qi Zheng X-Patchwork-Id: 13343923 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 8C661C41513 for ; Mon, 7 Aug 2023 11:36:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232855AbjHGLgA (ORCPT ); Mon, 7 Aug 2023 07:36:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42490 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232847AbjHGLfj (ORCPT ); Mon, 7 Aug 2023 07:35:39 -0400 Received: from mail-oi1-x22d.google.com (mail-oi1-x22d.google.com [IPv6:2607:f8b0:4864:20::22d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 23FF226AC for ; Mon, 7 Aug 2023 04:32:43 -0700 (PDT) Received: by mail-oi1-x22d.google.com with SMTP id 5614622812f47-3a7065d0f32so482581b6e.1 for ; Mon, 07 Aug 2023 04:32:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1691407908; x=1692012708; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=2n4eBW/y496rw0R30jGqgr9PaTd+TyGx4MFgxeJTY98=; b=iZx2esGQFAy+AXZzoGzlnkyLFaP/GQvoRu24PJHe06jl1dMzGsBtpHUM4xtH5MbkDa WufsG5ZOU28t//vK3THzVLJ24uwms75BR+xi3zl7tzp6SokOHeOsYSqTIevZt6xXFy0a tnoAK9MEnbBvTYGIRAIaRyPR4hJlzEsKXpntzqrOUbYtIY49g3XgGmnmeTlG51Occ6v7 G3I8VAl6VB5aVacfK8h4s6twOWAufF8KYBUjMIaJAHOWIW5WJTyfI3K0BAYiITt+mO9O X0NaEmjgE3WqGW328oJ4IJ7WRcXE7/x47K/dUVxyGaYWnv618pHKye6p89VkhHJE5xvP DDUw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1691407908; x=1692012708; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=2n4eBW/y496rw0R30jGqgr9PaTd+TyGx4MFgxeJTY98=; b=bG5yE4oTpCBjsWU2+070VugkPBGdZ4NeanQOKXPoj4p//TnmeFkvuOAtl75RJkaWu3 tqzzIVmzmETRA4FpW5NyMODBk4bs9DlKD7RlOYIKCeTjzltg5kSQrZLb9P7MEYgvwyB0 5S7/KMFTR7/mg7+UdUQZHc//2OGbJIETneV5iiP9wYQcV62VFii+A/hzfTJgst5d8wDA PBDdkEcabM+jQcTJ2/pkJRfbKQ1E9Av5V3bm3ZQziHqk+GWEdRA4nK9lHraqafNkavCA y2x1RaOa/32RbRgcRUmztEhRZEZ6FHXyahmDyccOjZz1J2k7gO8BCyWEFpagftBFnsyw sUvQ== X-Gm-Message-State: AOJu0YzgQDqAkdHCdmD6jHUULt7gLR8xXBfZqTZ4eeineWB/8S9hnZPE uFngy4dVcEdLHbs5AXh6r3KVuqCcWhLpOTB9Gaw= X-Google-Smtp-Source: APBJJlGfZoIKy5dlf67l9aDnuNmoWN294jSLFWBRn8Nrl68gwCTSSg7v4NaF4AAHW/6J0zEJitKJCg== X-Received: by 2002:a17:90a:1f83:b0:268:3dc6:f0c5 with SMTP id x3-20020a17090a1f8300b002683dc6f0c5mr25038018pja.0.1691406981820; Mon, 07 Aug 2023 04:16:21 -0700 (PDT) Received: from C02DW0BEMD6R.bytedance.net ([203.208.167.146]) by smtp.gmail.com with ESMTPSA id y13-20020a17090aca8d00b0025be7b69d73sm5861191pjt.12.2023.08.07.04.16.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 07 Aug 2023 04:16:21 -0700 (PDT) From: Qi Zheng To: akpm@linux-foundation.org, david@fromorbit.com, tkhai@ya.ru, vbabka@suse.cz, roman.gushchin@linux.dev, djwong@kernel.org, brauner@kernel.org, paulmck@kernel.org, tytso@mit.edu, steven.price@arm.com, cel@kernel.org, senozhatsky@chromium.org, yujie.liu@intel.com, gregkh@linuxfoundation.org, muchun.song@linux.dev, simon.horman@corigine.com, dlemoal@kernel.org Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org, kvm@vger.kernel.org, xen-devel@lists.xenproject.org, linux-erofs@lists.ozlabs.org, linux-f2fs-devel@lists.sourceforge.net, cluster-devel@redhat.com, linux-nfs@vger.kernel.org, linux-mtd@lists.infradead.org, rcu@vger.kernel.org, netdev@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-arm-msm@vger.kernel.org, dm-devel@redhat.com, linux-raid@vger.kernel.org, linux-bcache@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org, linux-btrfs@vger.kernel.org, Qi Zheng , Muchun Song Subject: [PATCH v4 30/48] vmw_balloon: dynamically allocate the vmw-balloon shrinker Date: Mon, 7 Aug 2023 19:09:18 +0800 Message-Id: <20230807110936.21819-31-zhengqi.arch@bytedance.com> X-Mailer: git-send-email 2.24.3 (Apple Git-128) In-Reply-To: <20230807110936.21819-1-zhengqi.arch@bytedance.com> References: <20230807110936.21819-1-zhengqi.arch@bytedance.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org In preparation for implementing lockless slab shrink, use new APIs to dynamically allocate the vmw-balloon shrinker, so that it can be freed asynchronously using kfree_rcu(). Then it doesn't need to wait for RCU read-side critical section when releasing the struct vmballoon. And we can simply exit vmballoon_init() when registering the shrinker fails. So the shrinker_registered indication is redundant, just remove it. Signed-off-by: Qi Zheng Reviewed-by: Muchun Song --- drivers/misc/vmw_balloon.c | 38 ++++++++++++-------------------------- 1 file changed, 12 insertions(+), 26 deletions(-) diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c index 9ce9b9e0e9b6..ac2cdb6cdf74 100644 --- a/drivers/misc/vmw_balloon.c +++ b/drivers/misc/vmw_balloon.c @@ -380,16 +380,7 @@ struct vmballoon { /** * @shrinker: shrinker interface that is used to avoid over-inflation. */ - struct shrinker shrinker; - - /** - * @shrinker_registered: whether the shrinker was registered. - * - * The shrinker interface does not handle gracefully the removal of - * shrinker that was not registered before. This indication allows to - * simplify the unregistration process. - */ - bool shrinker_registered; + struct shrinker *shrinker; }; static struct vmballoon balloon; @@ -1568,29 +1559,27 @@ static unsigned long vmballoon_shrinker_count(struct shrinker *shrinker, static void vmballoon_unregister_shrinker(struct vmballoon *b) { - if (b->shrinker_registered) - unregister_shrinker(&b->shrinker); - b->shrinker_registered = false; + shrinker_free(b->shrinker); } static int vmballoon_register_shrinker(struct vmballoon *b) { - int r; - /* Do nothing if the shrinker is not enabled */ if (!vmwballoon_shrinker_enable) return 0; - b->shrinker.scan_objects = vmballoon_shrinker_scan; - b->shrinker.count_objects = vmballoon_shrinker_count; - b->shrinker.seeks = DEFAULT_SEEKS; + b->shrinker = shrinker_alloc(0, "vmw-balloon"); + if (!b->shrinker) + return -ENOMEM; - r = register_shrinker(&b->shrinker, "vmw-balloon"); + b->shrinker->scan_objects = vmballoon_shrinker_scan; + b->shrinker->count_objects = vmballoon_shrinker_count; + b->shrinker->seeks = DEFAULT_SEEKS; + b->shrinker->private_data = b; - if (r == 0) - b->shrinker_registered = true; + shrinker_register(b->shrinker); - return r; + return 0; } /* @@ -1883,7 +1872,7 @@ static int __init vmballoon_init(void) error = vmballoon_register_shrinker(&balloon); if (error) - goto fail; + return error; /* * Initialization of compaction must be done after the call to @@ -1905,9 +1894,6 @@ static int __init vmballoon_init(void) vmballoon_debugfs_init(&balloon); return 0; -fail: - vmballoon_unregister_shrinker(&balloon); - return error; } /*