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=-15.8 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 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 E2D52C433EF for ; Wed, 8 Sep 2021 02:53:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CA9BD61108 for ; Wed, 8 Sep 2021 02:53:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347371AbhIHCyN (ORCPT ); Tue, 7 Sep 2021 22:54:13 -0400 Received: from mail.kernel.org ([198.145.29.99]:49746 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347339AbhIHCyK (ORCPT ); Tue, 7 Sep 2021 22:54:10 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id BDA5E61101; Wed, 8 Sep 2021 02:53:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1631069583; bh=+dxObjxH51aVY5Ln+C3HNBF7tR9KX13/wzZtl1/nrbs=; h=Date:From:To:Subject:In-Reply-To:From; b=jo4w/G/yEg7jmdk7s2Qv/b4p42zFLuDObX1xIv2QgTJkWEQe9dgK0vg58zEaIR/p+ XpYtSmlzdOr4oiBlJkPv4duR4HbizqOS+qVAc27yMfq5sE4U1FrT3WNbTXfiq8QESM aqUvFqGnyX+BAJy2cebvyHbEq19CWElbqGkw/PrE= Date: Tue, 07 Sep 2021 19:53:02 -0700 From: Andrew Morton To: akpm@linux-foundation.org, bigeasy@linutronix.de, brouer@redhat.com, cl@linux.com, efault@gmx.de, iamjoonsoo.kim@lge.com, jannh@google.com, linux-mm@kvack.org, mgorman@techsingularity.net, mm-commits@vger.kernel.org, penberg@kernel.org, quic_qiancai@quicinc.com, rientjes@google.com, tglx@linutronix.de, torvalds@linux-foundation.org, vbabka@suse.cz Subject: [patch 002/147] mm, slub: allocate private object map for debugfs listings Message-ID: <20210908025302.DbvVlK0Us%akpm@linux-foundation.org> In-Reply-To: <20210907195226.14b1d22a07c085b22968b933@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: Vlastimil Babka Subject: mm, slub: allocate private object map for debugfs listings Slub has a static spinlock protected bitmap for marking which objects are on freelist when it wants to list them, for situations where dynamically allocating such map can lead to recursion or locking issues, and on-stack bitmap would be too large. The handlers of debugfs files alloc_traces and free_traces also currently use this shared bitmap, but their syscall context makes it straightforward to allocate a private map before entering locked sections, so switch these processing paths to use a private bitmap. Link: https://lkml.kernel.org/r/20210904105003.11688-3-vbabka@suse.cz Signed-off-by: Vlastimil Babka Acked-by: Christoph Lameter Acked-by: Mel Gorman Cc: David Rientjes Cc: Jann Horn Cc: Jesper Dangaard Brouer Cc: Joonsoo Kim Cc: Mike Galbraith Cc: Pekka Enberg Cc: Qian Cai Cc: Sebastian Andrzej Siewior Cc: Thomas Gleixner Signed-off-by: Andrew Morton --- mm/slub.c | 44 +++++++++++++++++++++++++++++--------------- 1 file changed, 29 insertions(+), 15 deletions(-) --- a/mm/slub.c~mm-slub-allocate-private-object-map-for-debugfs-listings +++ a/mm/slub.c @@ -454,6 +454,18 @@ static inline bool cmpxchg_double_slab(s static unsigned long object_map[BITS_TO_LONGS(MAX_OBJS_PER_PAGE)]; static DEFINE_SPINLOCK(object_map_lock); +static void __fill_map(unsigned long *obj_map, struct kmem_cache *s, + struct page *page) +{ + void *addr = page_address(page); + void *p; + + bitmap_zero(obj_map, page->objects); + + for (p = page->freelist; p; p = get_freepointer(s, p)) + set_bit(__obj_to_index(s, addr, p), obj_map); +} + #if IS_ENABLED(CONFIG_KUNIT) static bool slab_add_kunit_errors(void) { @@ -483,17 +495,11 @@ static inline bool slab_add_kunit_errors static unsigned long *get_map(struct kmem_cache *s, struct page *page) __acquires(&object_map_lock) { - void *p; - void *addr = page_address(page); - VM_BUG_ON(!irqs_disabled()); spin_lock(&object_map_lock); - bitmap_zero(object_map, page->objects); - - for (p = page->freelist; p; p = get_freepointer(s, p)) - set_bit(__obj_to_index(s, addr, p), object_map); + __fill_map(object_map, s, page); return object_map; } @@ -4879,17 +4885,17 @@ static int add_location(struct loc_track } static void process_slab(struct loc_track *t, struct kmem_cache *s, - struct page *page, enum track_item alloc) + struct page *page, enum track_item alloc, + unsigned long *obj_map) { void *addr = page_address(page); void *p; - unsigned long *map; - map = get_map(s, page); + __fill_map(obj_map, s, page); + for_each_object(p, s, addr, page->objects) - if (!test_bit(__obj_to_index(s, addr, p), map)) + if (!test_bit(__obj_to_index(s, addr, p), obj_map)) add_location(t, s, get_track(s, p, alloc)); - put_map(map); } #endif /* CONFIG_DEBUG_FS */ #endif /* CONFIG_SLUB_DEBUG */ @@ -5816,14 +5822,21 @@ static int slab_debug_trace_open(struct struct loc_track *t = __seq_open_private(filep, &slab_debugfs_sops, sizeof(struct loc_track)); struct kmem_cache *s = file_inode(filep)->i_private; + unsigned long *obj_map; + + obj_map = bitmap_alloc(oo_objects(s->oo), GFP_KERNEL); + if (!obj_map) + return -ENOMEM; if (strcmp(filep->f_path.dentry->d_name.name, "alloc_traces") == 0) alloc = TRACK_ALLOC; else alloc = TRACK_FREE; - if (!alloc_loc_track(t, PAGE_SIZE / sizeof(struct location), GFP_KERNEL)) + if (!alloc_loc_track(t, PAGE_SIZE / sizeof(struct location), GFP_KERNEL)) { + bitmap_free(obj_map); return -ENOMEM; + } for_each_kmem_cache_node(s, node, n) { unsigned long flags; @@ -5834,12 +5847,13 @@ static int slab_debug_trace_open(struct spin_lock_irqsave(&n->list_lock, flags); list_for_each_entry(page, &n->partial, slab_list) - process_slab(t, s, page, alloc); + process_slab(t, s, page, alloc, obj_map); list_for_each_entry(page, &n->full, slab_list) - process_slab(t, s, page, alloc); + process_slab(t, s, page, alloc, obj_map); spin_unlock_irqrestore(&n->list_lock, flags); } + bitmap_free(obj_map); return 0; } _