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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 169C5C63798 for ; Fri, 20 Nov 2020 09:56:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B25E1222BA for ; Fri, 20 Nov 2020 09:56:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ffwll.ch header.i=@ffwll.ch header.b="NHf9AOhA" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727656AbgKTJ4S (ORCPT ); Fri, 20 Nov 2020 04:56:18 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46088 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727591AbgKTJ4Q (ORCPT ); Fri, 20 Nov 2020 04:56:16 -0500 Received: from mail-wr1-x441.google.com (mail-wr1-x441.google.com [IPv6:2a00:1450:4864:20::441]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 47820C0617A7 for ; Fri, 20 Nov 2020 01:56:14 -0800 (PST) Received: by mail-wr1-x441.google.com with SMTP id o15so9396294wru.6 for ; Fri, 20 Nov 2020 01:56:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=7+q8vKHO3EFjaJ879GkRcmDKHJR9JgE21VUyxKW3mY0=; b=NHf9AOhApOcnNW/Sr7K7lwSXd9Ck9Z5/C9QZ4NYblHO1KiG0SUmf/3/kmWsXvPhkQT 4FJM/oryQSQIsGzo7RJ1DYRxlHGoSPqMsoUII89W+KZZMQA32qYyL67Mj55nLL5PhTVd UhLCk32vlvzz7bBzhH/KI4Qlskc0xIQ5mkZWA= 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:in-reply-to :references:mime-version:content-transfer-encoding; bh=7+q8vKHO3EFjaJ879GkRcmDKHJR9JgE21VUyxKW3mY0=; b=SK7olneyjx4Wt9rftmG52kuc4tKp3ksV3DKot7ug85VWsGhORaZhdU+kRJN7bnX3sW 5we2Dg7U9/EemlbvvKCfbImXQx3bSnhNKw36s2dq4l9ZokeI23XtL9yz3nQIYrmmaff+ ZR691RiIZvQxpV6948L3SYRAZhW8KI/ZmNr4IQMQRpeFMTlXitfzHxrPibU5OZwkh6hV N4nbUmFjS33ORbuJU23r86Mt0++vtogUpcmra4bJSs7sDNl1jP+KBmNQepa2h06Qehh1 o2up/97PIzT/4vYn9LLi/bP8RmiTyuO1r1jVJcV71iIx5v4Wlr8wZSe0xmSVvpFe6a+9 iAyw== X-Gm-Message-State: AOAM5311wm01SpCKk8ZBong3MDsJgJ6v1nH19Zzd37luoin/llwHaZ9H h5qiTIkTabbVFTYKTxW2z1tkyw== X-Google-Smtp-Source: ABdhPJwJqZ9GhiqgSrImpdEVhjBbuglJqMxiUAwvoL3/huYCtyyfr42+HCgkw04wdaJDXAX4ODo8vQ== X-Received: by 2002:a5d:654b:: with SMTP id z11mr14013175wrv.291.1605866173041; Fri, 20 Nov 2020 01:56:13 -0800 (PST) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id t9sm4500208wrr.49.2020.11.20.01.56.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 20 Nov 2020 01:56:12 -0800 (PST) From: Daniel Vetter To: DRI Development Cc: Intel Graphics Development , linux-mm@kvack.org, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, LKML , Daniel Vetter , Vlastimil Babka , "Paul E . McKenney" , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Peter Zijlstra , Ingo Molnar , Mathieu Desnoyers , Sebastian Andrzej Siewior , Michel Lespinasse , Waiman Long , Thomas Gleixner , Randy Dunlap , Dave Chinner , Qian Cai , "Matthew Wilcox (Oracle)" , Daniel Vetter Subject: [PATCH 2/3] mm: Extract might_alloc() debug check Date: Fri, 20 Nov 2020 10:54:43 +0100 Message-Id: <20201120095445.1195585-3-daniel.vetter@ffwll.ch> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201120095445.1195585-1-daniel.vetter@ffwll.ch> References: <20201120095445.1195585-1-daniel.vetter@ffwll.ch> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Extracted from slab.h, which seems to have the most complete version including the correct might_sleep() check. Roll it out to slob.c. Motivated by a discussion with Paul about possibly changing call_rcu behaviour to allocate memory, but only roughly every 500th call. There are a lot fewer places in the kernel that care about whether allocating memory is allowed or not (due to deadlocks with reclaim code) than places that care whether sleeping is allowed. But debugging these also tends to be a lot harder, so nice descriptive checks could come in handy. I might have some use eventually for annotations in drivers/gpu. Note that unlike fs_reclaim_acquire/release gfpflags_allow_blocking does not consult the PF_MEMALLOC flags. But there is no flag equivalent for GFP_NOWAIT, hence this check can't go wrong due to memalloc_no*_save/restore contexts. Willy is working on a patch series which might change this: https://lore.kernel.org/linux-mm/20200625113122.7540-7-willy@infradead.org/ I think best would be if that updates gfpflags_allow_blocking(), since there's a ton of callers all over the place for that already. Acked-by: Vlastimil Babka Acked-by: Paul E. McKenney Cc: Paul E. McKenney Cc: Christoph Lameter Cc: Pekka Enberg Cc: David Rientjes Cc: Joonsoo Kim Cc: Andrew Morton Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Vlastimil Babka Cc: Mathieu Desnoyers Cc: Sebastian Andrzej Siewior Cc: Michel Lespinasse Cc: Daniel Vetter Cc: Waiman Long Cc: Thomas Gleixner Cc: Randy Dunlap Cc: linux-mm@kvack.org Cc: linux-fsdevel@vger.kernel.org Cc: Dave Chinner Cc: Qian Cai Cc: linux-xfs@vger.kernel.org Cc: "Matthew Wilcox (Oracle)" Signed-off-by: Daniel Vetter --- include/linux/sched/mm.h | 16 ++++++++++++++++ mm/slab.h | 5 +---- mm/slob.c | 6 ++---- 3 files changed, 19 insertions(+), 8 deletions(-) diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h index d5ece7a9a403..f94405d43fd1 100644 --- a/include/linux/sched/mm.h +++ b/include/linux/sched/mm.h @@ -180,6 +180,22 @@ static inline void fs_reclaim_acquire(gfp_t gfp_mask) { } static inline void fs_reclaim_release(gfp_t gfp_mask) { } #endif +/** + * might_alloc - Marks possible allocation sites + * @gfp_mask: gfp_t flags that would be use to allocate + * + * Similar to might_sleep() and other annotations this can be used in functions + * that might allocate, but often dont. Compiles to nothing without + * CONFIG_LOCKDEP. Includes a conditional might_sleep() if @gfp allows blocking. + */ +static inline void might_alloc(gfp_t gfp_mask) +{ + fs_reclaim_acquire(gfp_mask); + fs_reclaim_release(gfp_mask); + + might_sleep_if(gfpflags_allow_blocking(gfp_mask)); +} + /** * memalloc_noio_save - Marks implicit GFP_NOIO allocation scope. * diff --git a/mm/slab.h b/mm/slab.h index 6d7c6a5056ba..37b981247e5d 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -500,10 +500,7 @@ static inline struct kmem_cache *slab_pre_alloc_hook(struct kmem_cache *s, { flags &= gfp_allowed_mask; - fs_reclaim_acquire(flags); - fs_reclaim_release(flags); - - might_sleep_if(gfpflags_allow_blocking(flags)); + might_alloc(flags); if (should_failslab(s, flags)) return NULL; diff --git a/mm/slob.c b/mm/slob.c index 7cc9805c8091..8d4bfa46247f 100644 --- a/mm/slob.c +++ b/mm/slob.c @@ -474,8 +474,7 @@ __do_kmalloc_node(size_t size, gfp_t gfp, int node, unsigned long caller) gfp &= gfp_allowed_mask; - fs_reclaim_acquire(gfp); - fs_reclaim_release(gfp); + might_alloc(gfp); if (size < PAGE_SIZE - minalign) { int align = minalign; @@ -597,8 +596,7 @@ static void *slob_alloc_node(struct kmem_cache *c, gfp_t flags, int node) flags &= gfp_allowed_mask; - fs_reclaim_acquire(flags); - fs_reclaim_release(flags); + might_alloc(flags); if (c->size < PAGE_SIZE) { b = slob_alloc(c->size, flags, c->align, node, 0); -- 2.29.2