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 X-Spam-Level: X-Spam-Status: No, score=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6F36BC433B4 for ; Thu, 15 Apr 2021 11:56:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3D286610FA for ; Thu, 15 Apr 2021 11:56:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232517AbhDOL4y (ORCPT ); Thu, 15 Apr 2021 07:56:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32938 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230056AbhDOL4t (ORCPT ); Thu, 15 Apr 2021 07:56:49 -0400 Received: from mail-ej1-x631.google.com (mail-ej1-x631.google.com [IPv6:2a00:1450:4864:20::631]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C882FC061574 for ; Thu, 15 Apr 2021 04:56:26 -0700 (PDT) Received: by mail-ej1-x631.google.com with SMTP id w23so20624632ejb.9 for ; Thu, 15 Apr 2021 04:56:26 -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=MAgKFkUbajfTwkiBbjHCwLbY8LqpQ8PBmh7VA/cwU0E=; b=m1wDMNbKQex77GuTlU5+skb5l8cZdzF7kNI3HPNE8cQmGFBDeoAAfO3z62VHp2W3S6 g8hW0/7uNFuyEGt2cBpWlxY7pcdErauqg3dyEdRwrM0YzVCRm1joAJpAAV5NNdVsHQoF hahSKm6dCyKXf1Qc/eKCUHyZ69K7r1luODPcgcG5j0yP0ohshKObaq7m0ImYa5GWbCry 9Al1nVGzFju2O2/uydbJISxb5xBQhjAZqCnMhAz9VcnbR6pq5rT9YQjA3ZD+kQvHIDEE 6sfiAKFL4nt2J7KcscGOnWoI8wLfSRKUNDg4gXyWvv6+zlHwL+czM74h6/wzk/VJYSXm F+NA== 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=MAgKFkUbajfTwkiBbjHCwLbY8LqpQ8PBmh7VA/cwU0E=; b=BEkM7bzKBgqVtypGKDKk++6ZyQEyKjjURJyU+cQXR33eIcA3E3nxoNGp/1GjR7O1e+ qPJHC+ElRqrLIWP+dG/9m03cTTtX8VCAfQkpQoIEeFq9Wbo5AVtLcTZphHVcEJyVE+SQ 6hja7rZ6Hc4ZnDEQOepET4/BWDLL8jod2qkutXnYP8OtX0YYdfD8tim/4C3JLe/hJu2s NKhiBn+/UpLtTZZOr8y//yetLJQoEwO9KnzbeCco06QJTCBcqytg5Qa9NC2tARsArrDO WFd5lv1LwwSPN3V6iCSBmXrhh1+f96SpyOSoemsPh4jo4W5HBTwm0CjszzBWDrOMXFhj p3UQ== X-Gm-Message-State: AOAM5303mR+wht31yvpiJD39jW8BGk9Xb1Qef738IMF6SXPpC3N+t/Ts QwviYp57WnvPmAFy8OkgpBI= X-Google-Smtp-Source: ABdhPJwgvhGuyBEvsRLBj8pJVlv1MD8sM4alBQQIq3AaHw/fvXpcPyQjXZnukRoS19wBBYBX8H5fjg== X-Received: by 2002:a17:906:524f:: with SMTP id y15mr2973184ejm.65.1618487785620; Thu, 15 Apr 2021 04:56:25 -0700 (PDT) Received: from abel.fritz.box ([2a02:908:1252:fb60:3ba1:ccd9:cd93:a8ed]) by smtp.gmail.com with ESMTPSA id s9sm2182461edd.16.2021.04.15.04.56.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 15 Apr 2021 04:56:25 -0700 (PDT) From: "=?UTF-8?q?Christian=20K=C3=B6nig?=" X-Google-Original-From: =?UTF-8?q?Christian=20K=C3=B6nig?= To: linux-mm@kvack.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org Cc: vbabka@suse.cz, daniel@ffwll.ch, ray.huang@amd.com, akpm@linux-foundation.org Subject: [PATCH 1/2] mm/vmscan: add sync_shrinkers function Date: Thu, 15 Apr 2021 13:56:23 +0200 Message-Id: <20210415115624.2904-1-christian.koenig@amd.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org To be able to switch to a spinlock and reduce lock contention in the TTM shrinker we don't want to hold a mutex while unmapping and freeing pages from the pool. But then we somehow need to prevent a race between (for example) the shrinker trying to free pages and hotplug trying to remove the device which those pages belong to. Taking and releasing the shrinker semaphore on the write side after unmapping and freeing all pages should make sure that no shrinker is running in paralell any more. Signed-off-by: Christian König --- include/linux/shrinker.h | 1 + mm/vmscan.c | 10 ++++++++++ 2 files changed, 11 insertions(+) diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h index 0f80123650e2..6b75dc372fce 100644 --- a/include/linux/shrinker.h +++ b/include/linux/shrinker.h @@ -92,4 +92,5 @@ extern void register_shrinker_prepared(struct shrinker *shrinker); extern int register_shrinker(struct shrinker *shrinker); extern void unregister_shrinker(struct shrinker *shrinker); extern void free_prealloced_shrinker(struct shrinker *shrinker); +extern void sync_shrinkers(void); #endif diff --git a/mm/vmscan.c b/mm/vmscan.c index 562e87cbd7a1..46cd9c215d73 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -408,6 +408,16 @@ void unregister_shrinker(struct shrinker *shrinker) } EXPORT_SYMBOL(unregister_shrinker); +/** + * sync_shrinker - Wait for all running shrinkers to complete. + */ +void sync_shrinkers(void) +{ + down_write(&shrinker_rwsem); + up_write(&shrinker_rwsem); +} +EXPORT_SYMBOL(sync_shrinkers); + #define SHRINK_BATCH 128 static unsigned long do_shrink_slab(struct shrink_control *shrinkctl, -- 2.25.1