From patchwork Wed Nov 25 16:25:30 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Vetter X-Patchwork-Id: 11931473 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=-16.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,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 890AFC64E7B for ; Wed, 25 Nov 2020 16:25:45 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A888D2083E for ; Wed, 25 Nov 2020 16:25:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=ffwll.ch header.i=@ffwll.ch header.b="QMYNGEeA" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A888D2083E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ffwll.ch Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 0567B6EA18; Wed, 25 Nov 2020 16:25:44 +0000 (UTC) Received: from mail-wm1-x344.google.com (mail-wm1-x344.google.com [IPv6:2a00:1450:4864:20::344]) by gabe.freedesktop.org (Postfix) with ESMTPS id C0B5C6EA18 for ; Wed, 25 Nov 2020 16:25:42 +0000 (UTC) Received: by mail-wm1-x344.google.com with SMTP id a186so2512957wme.1 for ; Wed, 25 Nov 2020 08:25:42 -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=UNSb6Wp1AZE4VV1tRwOeD55taeEGpBqVtqBoZlJ/7FM=; b=QMYNGEeA4YfhfQORAYeqBZnZcsSUcenw0mAE059wCrKDDwvxV6pkAgR4/U23dLWec0 RevBzZUbIN+mA+zBM07VEiG7Y25QELLdsH60N6ottEwiWDuwJQpLTRsg7/QipBmILxir xUhl44+qhKqBTkmVewpxVXpAPVi4yZQtwpPgw= 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=UNSb6Wp1AZE4VV1tRwOeD55taeEGpBqVtqBoZlJ/7FM=; b=q64xWWt+HiU1kfwXGziGjcZRSRrGyH2olL92BTqNymO0xmENv+axZtuEKYvsHzg4Kn UuhfjahptdgtCZxBcRIP+t+blwdNEeF9gCsTa3GMxkr0GHFXv4Ze0dlgbGix1bAYT2hq w0/nMFfVLiaiDW8ggeflpJcNclXAz+ZhhVru4sn8SFNarD13TuH4ULign9HifyjNTCEb yQDaeIwP9N+dyN7kFFOE8QZ6gBogefqo/ABycQf5roeuQnNTA0W4/xRwhFgIeE4acFWY w+qjMdQBNooexr6e8nCmcoIa+1XbT3mI1A7YSsgLw+g7RrhlQ71E1JHVcX8OxwKhs6n4 Ikxg== X-Gm-Message-State: AOAM533mJDcNfHEv/4yyUuPqnRgzOlV6sGW5AWnoCZPggih2MdLVByy2 VoY5R4xKb+eJ52JhRAmbhlvpCA== X-Google-Smtp-Source: ABdhPJy7GHHP/Ip7I6Y1Tn4QI7dFjHyZUmuEZ7U3OT2GK1eKINNZ3obuKDnLln9NKOQlPoUBDiVX7A== X-Received: by 2002:a1c:6209:: with SMTP id w9mr4886901wmb.120.1606321541410; Wed, 25 Nov 2020 08:25:41 -0800 (PST) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id a21sm4855187wmb.38.2020.11.25.08.25.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 25 Nov 2020 08:25:40 -0800 (PST) From: Daniel Vetter To: DRI Development Date: Wed, 25 Nov 2020 17:25:30 +0100 Message-Id: <20201125162532.1299794-3-daniel.vetter@ffwll.ch> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201125162532.1299794-1-daniel.vetter@ffwll.ch> References: <20201125162532.1299794-1-daniel.vetter@ffwll.ch> MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH v4 2/3] mm: Extract might_alloc() debug check X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Zijlstra , Daniel Vetter , Sebastian Andrzej Siewior , Dave Chinner , linux-mm@kvack.org, Daniel Vetter , Christoph Lameter , Michel Lespinasse , Ingo Molnar , linux-xfs@vger.kernel.org, "Matthew Wilcox \(Oracle\)" , Jason Gunthorpe , David Rientjes , Waiman Long , "Paul E . McKenney" , Intel Graphics Development , Mathieu Desnoyers , Thomas Gleixner , Joonsoo Kim , Vlastimil Babka , Randy Dunlap , LKML , Pekka Enberg , linux-fsdevel@vger.kernel.org, Qian Cai , Andrew Morton Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" 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. v2: Fix typos in kerneldoc (Randy) Acked-by: Vlastimil Babka Acked-by: Paul E. McKenney Reviewed-by: Jason Gunthorpe Cc. Randy Dunlap 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..a11a61b5226f 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 - Mark possible allocation sites + * @gfp_mask: gfp_t flags that would be used to allocate + * + * Similar to might_sleep() and other annotations, this can be used in functions + * that might allocate, but often don't. 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);