From patchwork Fri Oct 23 12:21:15 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Vetter X-Patchwork-Id: 11852867 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6A88F16BC for ; Fri, 23 Oct 2020 12:22:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4DC4C24641 for ; Fri, 23 Oct 2020 12:22:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ffwll.ch header.i=@ffwll.ch header.b="GgfqsG68" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S463589AbgJWMW2 (ORCPT ); Fri, 23 Oct 2020 08:22:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37870 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S463586AbgJWMW2 (ORCPT ); Fri, 23 Oct 2020 08:22:28 -0400 Received: from mail-wr1-x443.google.com (mail-wr1-x443.google.com [IPv6:2a00:1450:4864:20::443]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6FF1EC0613D5 for ; Fri, 23 Oct 2020 05:22:27 -0700 (PDT) Received: by mail-wr1-x443.google.com with SMTP id n15so1596535wrq.2 for ; Fri, 23 Oct 2020 05:22:27 -0700 (PDT) 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=Md4YAXpjpdGTyHyAgh2ay+AKQEd8Ro2fcgd8T+fjD4o=; b=GgfqsG68s8RU3qED2SP+ReACq0NGvEMRdgsY6b6ebZqvXlKJoL/Mx/M9P+m8eu/R51 JiE6HK/crlCj0SnKoHO/QCCI3VkmWtqVIAyu4QXV/TZTZHYUHURHT9eDDCsbRIL7hGE7 uWyhojoODyHuN4DFjcfQ46NFY2Khc8hMcQmkE= 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=Md4YAXpjpdGTyHyAgh2ay+AKQEd8Ro2fcgd8T+fjD4o=; b=KnRm/dWmQZe88bnm9kp4zTH3Ft0yFXKuISqagD/fErW/xfgh6C7O1e24xKSF4+taul FeiLxyZhjuMjAsoAsRUoVhwT5cLgIOnrMt4WITHG6aWHQ55Tzsw/ld7uDUIj8qTSKZDs xxrXu5Gu+tIDkR3yQRHX6fOYIFug7+D/gVOQGpjal5fGTjrOIFDStDlStALYHzmEriqQ I42Hke5l5Xsr55G8z7RK+FMAZQ3N2SwwB6JnnqyM4QdTdDNmOeuEMhqHThjsLQe/tsoc fwbU8dkDpRiqMw888dKBuVqqdt6COeg7NEu6e0k171znOzE2Z48gFz/1T99vDvKDYrzV MMXQ== X-Gm-Message-State: AOAM531TEeY/tSWz2u6y8tv2h60dor0dJWKMpUoUrMbXpllVHy+/+bbu UXu5u4l0e/FUXVbFk3tEvFRPpQ== X-Google-Smtp-Source: ABdhPJwY3k8N8hWJAzZAqbhvx4fpSD2M0kW3wHfJxLbpQ9x79iQZHoLA9FsW4Ur15mgIydU2Qpf3mw== X-Received: by 2002:adf:f4ca:: with SMTP id h10mr2271950wrp.89.1603455746195; Fri, 23 Oct 2020 05:22:26 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id y4sm3056484wrp.74.2020.10.23.05.22.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 23 Oct 2020 05:22:25 -0700 (PDT) From: Daniel Vetter To: DRI Development Cc: Intel Graphics Development , Daniel Vetter , "Paul E . McKenney" , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Peter Zijlstra , Ingo Molnar , Vlastimil Babka , Mathieu Desnoyers , Sebastian Andrzej Siewior , Michel Lespinasse , Waiman Long , Thomas Gleixner , Randy Dunlap , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Dave Chinner , Qian Cai , linux-xfs@vger.kernel.org, Daniel Vetter Subject: [PATCH 04/65] mm: Extract might_alloc() debug check Date: Fri, 23 Oct 2020 14:21:15 +0200 Message-Id: <20201023122216.2373294-4-daniel.vetter@ffwll.ch> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20201023122216.2373294-1-daniel.vetter@ffwll.ch> References: <20201021163242.1458885-1-daniel.vetter@ffwll.ch> <20201023122216.2373294-1-daniel.vetter@ffwll.ch> MIME-Version: 1.0 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. 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 Signed-off-by: Daniel Vetter Acked-by: Vlastimil Babka Acked-by: Paul E. McKenney --- 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 f889e332912f..2b0037abac0b 100644 --- a/include/linux/sched/mm.h +++ b/include/linux/sched/mm.h @@ -205,6 +205,22 @@ 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 6cc323f1313a..fedd789b2270 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -492,10 +492,7 @@ 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);