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 CA2E5C433FE for ; Wed, 8 Sep 2021 02:54:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B444E610C9 for ; Wed, 8 Sep 2021 02:54:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347231AbhIHCzI (ORCPT ); Tue, 7 Sep 2021 22:55:08 -0400 Received: from mail.kernel.org ([198.145.29.99]:51020 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347363AbhIHCzF (ORCPT ); Tue, 7 Sep 2021 22:55:05 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id B6B12610C9; Wed, 8 Sep 2021 02:53:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1631069638; bh=qvRCEQBSzC2pVeSWwfu3kW7uRYyi52qtmFtpBzKcEmM=; h=Date:From:To:Subject:In-Reply-To:From; b=HQUTY/tDrWMBCtyAuGZoL9htbsndyCkf6Jvssp8w4ON81KuTs00hL34m+Y1ihnHdd sE8tP230XFSO8keptFMuNbqhzyx3wWjX+5Rrd6hjS3x42SHPneYLZw9J/zvlFRlAVP /TVdqdN6/+xx8Sis9KugZtminnQKMW+xkRM+eU2I= Date: Tue, 07 Sep 2021 19:53:57 -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 019/147] mm, slub: make locking in deactivate_slab() irq-safe Message-ID: <20210908025357.WfR3N8cVl%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: make locking in deactivate_slab() irq-safe deactivate_slab() now no longer touches the kmem_cache_cpu structure, so it will be possible to call it with irqs enabled. Just convert the spin_lock calls to their irq saving/restoring variants to make it irq-safe. Note we now have to use cmpxchg_double_slab() for irq-safe slab_lock(), because in some situations we don't take the list_lock, which would disable irqs. Link: https://lkml.kernel.org/r/20210904105003.11688-20-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: Qian Cai Cc: Sebastian Andrzej Siewior Cc: Thomas Gleixner Signed-off-by: Andrew Morton --- mm/slub.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) --- a/mm/slub.c~mm-slub-make-locking-in-deactivate_slab-irq-safe +++ a/mm/slub.c @@ -2223,6 +2223,7 @@ static void deactivate_slab(struct kmem_ enum slab_modes l = M_NONE, m = M_NONE; void *nextfree, *freelist_iter, *freelist_tail; int tail = DEACTIVATE_TO_HEAD; + unsigned long flags = 0; struct page new; struct page old; @@ -2298,7 +2299,7 @@ redo: * that acquire_slab() will see a slab page that * is frozen */ - spin_lock(&n->list_lock); + spin_lock_irqsave(&n->list_lock, flags); } } else { m = M_FULL; @@ -2309,7 +2310,7 @@ redo: * slabs from diagnostic functions will not see * any frozen slabs. */ - spin_lock(&n->list_lock); + spin_lock_irqsave(&n->list_lock, flags); } } @@ -2326,14 +2327,14 @@ redo: } l = m; - if (!__cmpxchg_double_slab(s, page, + if (!cmpxchg_double_slab(s, page, old.freelist, old.counters, new.freelist, new.counters, "unfreezing slab")) goto redo; if (lock) - spin_unlock(&n->list_lock); + spin_unlock_irqrestore(&n->list_lock, flags); if (m == M_PARTIAL) stat(s, tail); _