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 5A5A3C433ED for ; Fri, 9 Apr 2021 07:17:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2D98E61178 for ; Fri, 9 Apr 2021 07:17:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231698AbhDIHRp (ORCPT ); Fri, 9 Apr 2021 03:17:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45966 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231497AbhDIHRm (ORCPT ); Fri, 9 Apr 2021 03:17:42 -0400 Received: from mail-ej1-x636.google.com (mail-ej1-x636.google.com [IPv6:2a00:1450:4864:20::636]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2730FC061760 for ; Fri, 9 Apr 2021 00:17:28 -0700 (PDT) Received: by mail-ej1-x636.google.com with SMTP id r9so7055610ejj.3 for ; Fri, 09 Apr 2021 00:17:28 -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=igEspD4oLTpM4o2jCwSGcYwjzgvaFDiBYrZde/yigoCOzASZ6Q36kFdOLTPk9+sEKA At9Rg6okYKLJenOHCVlutmLzuLAhyDZfgGBYJ66Oj8C6MPsS8wita034AoWkMFIgC25Z 7hsoj7iGl8V5wzeL/wT3tqHTfrZTHkZwk5UBViKyHTywBmZFq0frm8mI3J2xlddZBmoE s8q8GSI2WepiZ10MAzwDGwDMtYCoPpkyTnDhEtIa1GyGDEw6k37Rs+HJ9yff6WL6sw1O 4WqcJX+pPtmQilHkwSI8hffyk+1BcLWllcyd2nRmfoTOw/Abay7/0UE6y0hP+L+s4Qlb YxuQ== 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=t7SK7OPceOKhYtKxol1DrgJR/gY/1oiywnJWRSULInEIy34GE5uGeM42FYZtrjEnKX GQ/pOT+ImfouvZStczPVS37gvZ7MCXfIbICQXfFi+BSoXAAC2QRpe872TD5tmG5hp0Dd oO6ZohuuHMZEng/IxzLr3sKIfEwYUeo3qleJvEovqCD4TjBorOOpAfFFIOsbEAbKPCTi 7p6NcRYx56HIz5KbURBtaR30mDToTxX9DbHDyWlN+9VRyRQJII0PsWsXwqHiaZ5f0XIp AOyv8ju+khBn6OxvPw6o44XBxVLyrzNBPD6cfswKiW+SWI3DfT80lGGjfqIMCNiSNnn6 N5Gg== X-Gm-Message-State: AOAM530zfb9oAarlpv6hYqUUD6koTr6aRyQkZtAYXbaowVGTNIdQjBw8 G4RBUJvXJFahanN7Qmmt0KM= X-Google-Smtp-Source: ABdhPJzQ2tCFOmAsi20Gal6ccZzgbiWTy3xs28H9Fe7zY+J/NCEjtr1WZzzVEoA6J7yNPFrn15rtkw== X-Received: by 2002:a17:906:5618:: with SMTP id f24mr15226911ejq.414.1617952646960; Fri, 09 Apr 2021 00:17:26 -0700 (PDT) Received: from abel.fritz.box ([2a02:908:1252:fb60:216f:9340:7a2b:4f98]) by smtp.gmail.com with ESMTPSA id w1sm905369edt.89.2021.04.09.00.17.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 09 Apr 2021 00:17:26 -0700 (PDT) From: "=?UTF-8?q?Christian=20K=C3=B6nig?=" X-Google-Original-From: =?UTF-8?q?Christian=20K=C3=B6nig?= To: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: ray.huang@amd.com, daniel@ffwll.ch, akpm@linux-foundation.org Subject: [PATCH 1/2] mm/vmscan: add sync_shrinkers function Date: Fri, 9 Apr 2021 09:17:24 +0200 Message-Id: <20210409071725.1532-1-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