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=-18.8 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,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 9711DC48BCF for ; Wed, 9 Jun 2021 11:41:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6D31661359 for ; Wed, 9 Jun 2021 11:41:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239487AbhFILn2 (ORCPT ); Wed, 9 Jun 2021 07:43:28 -0400 Received: from smtp-out1.suse.de ([195.135.220.28]:54870 "EHLO smtp-out1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239186AbhFILld (ORCPT ); Wed, 9 Jun 2021 07:41:33 -0400 Received: from imap.suse.de (imap-alt.suse-dmz.suse.de [192.168.254.47]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id EBBAB219F0; Wed, 9 Jun 2021 11:39:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1623238777; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=kIsSOg2ibGFfBt24mwRJ/OtudI5KuCKn5sZ6lfdE+UY=; b=SAXljtSeuHX/AHMDvIbkcGQIAoE8DuboaCglNFU8aJf5EpSJzDrROkRuBnPLJy7vOhJ6gC sUb5CPMdHaJHJxg9Dsq6ASLRETL+axkYEZ3k8/WQy4WRnX8WdgEhGtk3Q6lLc+6jBIii5Q ImYH3mQlApaHg/KxsPLT110QSUOndMg= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1623238777; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=kIsSOg2ibGFfBt24mwRJ/OtudI5KuCKn5sZ6lfdE+UY=; b=CyW5d6D60EvIJEIiToc1ZOBwDgnQZJRRu1bZVUD3cI1+z8myUsHQ/SBge2sezlGaCXJHdJ kzPZ4ApGO9sHxeCg== Received: from imap3-int (imap-alt.suse-dmz.suse.de [192.168.254.47]) by imap.suse.de (Postfix) with ESMTP id BD017118DD; Wed, 9 Jun 2021 11:39:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1623238777; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=kIsSOg2ibGFfBt24mwRJ/OtudI5KuCKn5sZ6lfdE+UY=; b=SAXljtSeuHX/AHMDvIbkcGQIAoE8DuboaCglNFU8aJf5EpSJzDrROkRuBnPLJy7vOhJ6gC sUb5CPMdHaJHJxg9Dsq6ASLRETL+axkYEZ3k8/WQy4WRnX8WdgEhGtk3Q6lLc+6jBIii5Q ImYH3mQlApaHg/KxsPLT110QSUOndMg= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1623238777; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=kIsSOg2ibGFfBt24mwRJ/OtudI5KuCKn5sZ6lfdE+UY=; b=CyW5d6D60EvIJEIiToc1ZOBwDgnQZJRRu1bZVUD3cI1+z8myUsHQ/SBge2sezlGaCXJHdJ kzPZ4ApGO9sHxeCg== Received: from director2.suse.de ([192.168.254.72]) by imap3-int with ESMTPSA id CKiuLXmowGD6XgAALh3uQQ (envelope-from ); Wed, 09 Jun 2021 11:39:37 +0000 From: Vlastimil Babka To: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Christoph Lameter , David Rientjes , Pekka Enberg , Joonsoo Kim Cc: Sebastian Andrzej Siewior , Thomas Gleixner , Mel Gorman , Jesper Dangaard Brouer , Peter Zijlstra , Jann Horn , Vlastimil Babka Subject: [RFC v2 32/34] mm, slub: make slab_lock() disable irqs with PREEMPT_RT Date: Wed, 9 Jun 2021 13:39:01 +0200 Message-Id: <20210609113903.1421-33-vbabka@suse.cz> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210609113903.1421-1-vbabka@suse.cz> References: <20210609113903.1421-1-vbabka@suse.cz> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We need to disable irqs around slab_lock() (a bit spinlock) to make it irq-safe. The calls to slab_lock() are nested under spin_lock_irqsave() which doesn't disable irqs on PREEMPT_RT, so add explicit disabling with PREEMPT_RT. We also distinguish cmpxchg_double_slab() where we do the disabling explicitly and __cmpxchg_double_slab() for contexts with already disabled irqs. However these context are also typically spin_lock_irqsave() thus insufficient on PREEMPT_RT. Thus, change __cmpxchg_double_slab() to be same as cmpxchg_double_slab() on PREEMPT_RT. Signed-off-by: Vlastimil Babka --- mm/slub.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index 6721169f816d..12e966f07f19 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -374,12 +374,12 @@ __slab_unlock(struct page *page, unsigned long *flags, bool disable_irqs) static __always_inline void slab_lock(struct page *page, unsigned long *flags) { - __slab_lock(page, flags, false); + __slab_lock(page, flags, IS_ENABLED(CONFIG_PREEMPT_RT)); } static __always_inline void slab_unlock(struct page *page, unsigned long *flags) { - __slab_unlock(page, flags, false); + __slab_unlock(page, flags, IS_ENABLED(CONFIG_PREEMPT_RT)); } static inline bool ___cmpxchg_double_slab(struct kmem_cache *s, struct page *page, @@ -422,14 +422,19 @@ static inline bool ___cmpxchg_double_slab(struct kmem_cache *s, struct page *pag return false; } -/* Interrupts must be disabled (for the fallback code to work right) */ +/* + * Interrupts must be disabled (for the fallback code to work right), typically + * by an _irqsave() lock variant. Except on PREEMPT_RT where locks are different + * so we disable interrupts explicitly here. + */ static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct page *page, void *freelist_old, unsigned long counters_old, void *freelist_new, unsigned long counters_new, const char *n) { return ___cmpxchg_double_slab(s, page, freelist_old, counters_old, - freelist_new, counters_new, n, false); + freelist_new, counters_new, n, + IS_ENABLED(CONFIG_PREEMPT_RT)); } static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page, -- 2.31.1