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 F07FCC433FE for ; Thu, 2 Sep 2021 21:51:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DBD78610F9 for ; Thu, 2 Sep 2021 21:51:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347596AbhIBVw0 (ORCPT ); Thu, 2 Sep 2021 17:52:26 -0400 Received: from mail.kernel.org ([198.145.29.99]:44050 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347589AbhIBVwT (ORCPT ); Thu, 2 Sep 2021 17:52:19 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id E41E5610F7; Thu, 2 Sep 2021 21:51:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1630619480; bh=KLW3zlTEk6MnfXQuMalXMXDfjNb0eBngh6B1W+PhajA=; h=Date:From:To:Subject:In-Reply-To:From; b=DehkrUTMJPeOfcF+RaPiRO3ik3oa3qLPw3/YRfv0Z/uT1cLo2s+uW7O/XWRpjFoiu +j6aLAtQyibIScf4pdNcvvRjGxYXrVIJ6+SULnR4nnDdWGKINFUrdhvzjSKgCiNi67 TrlgjrJ7qE7MGHjyvMbA4El3xdPC9scxIa0Px290= Date: Thu, 02 Sep 2021 14:51:19 -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, rientjes@google.com, tglx@linutronix.de, torvalds@linux-foundation.org, vbabka@suse.cz Subject: [patch 026/212] mm, slub: stop disabling irqs around get_partial() Message-ID: <20210902215119.G4eCgHSjE%akpm@linux-foundation.org> In-Reply-To: <20210902144820.78957dff93d7bea620d55a89@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: stop disabling irqs around get_partial() The function get_partial() does not need to have irqs disabled as a whole. It's sufficient to convert spin_lock operations to their irq saving/restoring versions. As a result, it's now possible to reach the page allocator from the slab allocator without disabling and re-enabling interrupts on the way. Link: https://lkml.kernel.org/r/20210805152000.12817-19-vbabka@suse.cz Signed-off-by: Vlastimil Babka Cc: Christoph Lameter Cc: David Rientjes Cc: Jann Horn Cc: Jesper Dangaard Brouer Cc: Joonsoo Kim Cc: Mel Gorman Cc: Mike Galbraith Cc: Pekka Enberg Cc: Sebastian Andrzej Siewior Cc: Thomas Gleixner Signed-off-by: Andrew Morton --- mm/slub.c | 22 ++++++++-------------- 1 file changed, 8 insertions(+), 14 deletions(-) --- a/mm/slub.c~mm-slub-stop-disabling-irqs-around-get_partial +++ a/mm/slub.c @@ -1996,11 +1996,12 @@ static inline bool pfmemalloc_match(stru * Try to allocate a partial slab from a specific node. */ static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n, - struct page **ret_page, gfp_t flags) + struct page **ret_page, gfp_t gfpflags) { struct page *page, *page2; void *object = NULL; unsigned int available = 0; + unsigned long flags; int objects; /* @@ -2012,11 +2013,11 @@ static void *get_partial_node(struct kme if (!n || !n->nr_partial) return NULL; - spin_lock(&n->list_lock); + spin_lock_irqsave(&n->list_lock, flags); list_for_each_entry_safe(page, page2, &n->partial, slab_list) { void *t; - if (!pfmemalloc_match(page, flags)) + if (!pfmemalloc_match(page, gfpflags)) continue; t = acquire_slab(s, n, page, object == NULL, &objects); @@ -2037,7 +2038,7 @@ static void *get_partial_node(struct kme break; } - spin_unlock(&n->list_lock); + spin_unlock_irqrestore(&n->list_lock, flags); return object; } @@ -2765,8 +2766,10 @@ new_slab: local_irq_restore(flags); goto reread_page; } - if (unlikely(!slub_percpu_partial(c))) + if (unlikely(!slub_percpu_partial(c))) { + local_irq_restore(flags); goto new_objects; /* stolen by an IRQ handler */ + } page = c->page = slub_percpu_partial(c); slub_set_percpu_partial(c, page); @@ -2775,18 +2778,9 @@ new_slab: goto redo; } - local_irq_save(flags); - if (unlikely(c->page)) { - local_irq_restore(flags); - goto reread_page; - } - new_objects: - lockdep_assert_irqs_disabled(); - freelist = get_partial(s, gfpflags, node, &page); - local_irq_restore(flags); if (freelist) goto check_new_page; _