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=-4.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 18E8BC48BCD for ; Wed, 9 Jun 2021 22:29:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F33C3613C8 for ; Wed, 9 Jun 2021 22:29:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229753AbhFIWbS (ORCPT ); Wed, 9 Jun 2021 18:31:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60372 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229526AbhFIWbP (ORCPT ); Wed, 9 Jun 2021 18:31:15 -0400 Received: from mail-lj1-x229.google.com (mail-lj1-x229.google.com [IPv6:2a00:1450:4864:20::229]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E9AAFC061574 for ; Wed, 9 Jun 2021 15:29:19 -0700 (PDT) Received: by mail-lj1-x229.google.com with SMTP id e2so1897919ljk.4 for ; Wed, 09 Jun 2021 15:29:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=M7Xu6kMcR2et3beJeKJaJObrep7udVBP5n2divRH1FM=; b=rdDQNK6m4jBlvDuU6bj+Gzw97BzicOCqW2SQgUTxN1TGC40Fw2yss+gJi6MWcOVsJS OvFg0w6wS/wmMV+DrcCRYgKAA+zxaPqdQO3BWMYzShEAJg1JTIhfR1ZGyomrmeHMHR6G lhQUGQczHRk25hSA8nsRCpR4Ii5BNqkPyzHr1wGVP1nvx0j83DvMLqohL50E8WXDzmSb pi7rUsuA13cgqqGUb1J+ZgVqql3wtd61RW49VTj5u6VGEoabJ6F3SezzuSfRJZekONzQ OSIkWKfQz2H9BE4pdc+XaUYbzwjOxV7pQtN2cCF/jPNi3RlZWKCRfQCwWLnrhE7z+SDe SSvA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=M7Xu6kMcR2et3beJeKJaJObrep7udVBP5n2divRH1FM=; b=Dbq2RF9OeIw4xuNup6cnHh2QBuYiBRiFx9Pr/VGKNy4CtD5AhUeExrocg5yTc6wtBl SvyrI7UvrQS64OgeoIhe1Fnbk+GPQEcKazzKHbB4o11cGGVf8EUudAV3tUmNHXwntB4i nSm8WYM7BcSfhYcCBUFk8x7el25/8nl7jYE+iFrP4TAC9N9FNh/13LsJ991CdcaipjtD n5cn/fOqZdCQlYxZYqzsjxeV4GwOLRnL2sRNMxIDRDp21SVmqbMsP2kxPYUtDOwtEkTM fSsk1hIeYXf9wc4487iKAtGTdn73gj3jQddcXuQpgCpfGKmIk0fA+hmFGSH5DBhAozQW NxEQ== X-Gm-Message-State: AOAM5306JCDIjKQHkJAKXbyr+0HVPgmNkNn+aYWIJ9QW7k7bydbqFKAk AdsSGrWmRTrzLtq73AKjTx+wp0ceAbI= X-Google-Smtp-Source: ABdhPJwjAK958nvDVvTjhGuLwBhggZDV71YKEl5Amb+3n969qP4LK47e6wnU+Vn5pI7X+hBVp7xxhA== X-Received: by 2002:a05:651c:1057:: with SMTP id x23mr1382097ljm.467.1623277758099; Wed, 09 Jun 2021 15:29:18 -0700 (PDT) Received: from grain.localdomain ([5.18.171.94]) by smtp.gmail.com with ESMTPSA id r3sm111100ljc.20.2021.06.09.15.29.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 09 Jun 2021 15:29:16 -0700 (PDT) Received: by grain.localdomain (Postfix, from userid 1000) id C25C85A0041; Thu, 10 Jun 2021 01:29:15 +0300 (MSK) Date: Thu, 10 Jun 2021 01:29:15 +0300 From: Cyrill Gorcunov To: Vlastimil Babka Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Christoph Lameter , David Rientjes , Pekka Enberg , Joonsoo Kim , Sebastian Andrzej Siewior , Thomas Gleixner , Mel Gorman , Jesper Dangaard Brouer , Peter Zijlstra , Jann Horn Subject: Re: [RFC v2 29/34] mm: slub: Move flush_cpu_slab() invocations __free_slab() invocations out of IRQ context Message-ID: References: <20210609113903.1421-1-vbabka@suse.cz> <20210609113903.1421-30-vbabka@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210609113903.1421-30-vbabka@suse.cz> User-Agent: Mutt/2.0.7 (2021-05-04) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 09, 2021 at 01:38:58PM +0200, Vlastimil Babka wrote: > +static DEFINE_MUTEX(flush_lock); > +static DEFINE_PER_CPU(struct slub_flush_work, slub_flush); > + > static void flush_all(struct kmem_cache *s) > { > - on_each_cpu_cond(has_cpu_slab, flush_cpu_slab, s, 1); > + struct slub_flush_work *sfw; > + unsigned int cpu; > + > + cpus_read_lock(); > + mutex_lock(&flush_lock); > + Hi, Vlastimil! Could you please point why do you lock cpus first and mutex only after? Why not mutex_lock + cpus_read_lock instead?