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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 63E7EC6FD1C for ; Wed, 22 Mar 2023 15:01:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229973AbjCVPBP (ORCPT ); Wed, 22 Mar 2023 11:01:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45276 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230328AbjCVPBM (ORCPT ); Wed, 22 Mar 2023 11:01:12 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6C51915557; Wed, 22 Mar 2023 08:01:07 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id A0492B81CF4; Wed, 22 Mar 2023 15:01:05 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7036AC433EF; Wed, 22 Mar 2023 15:01:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1679497264; bh=rK4fyj+3bFI3UORG7apfsrTb82JTbZ64Z4g0fMI2vnw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=JYwOpSXlIN5RJomg9drFUx2vQ9A1FIwpMJJj+jIZJnC0cpiClSkUb30pJZARvG9NS +wvSQkt0iZp/xLOWqCihJUOjCuNpug1wTHldt2eCzEOZ7WaaQO2Tew4SJCWAm/xA+1 d7ZpLgkCz91H/cmsBzNIEXGLbsOZ/XIg2DdQjLHo5uhaiP6C5XoqkynRV+t02OKvqU ylGiRXI83yigTTWx3DJBU/IvKwUiFIE0AH/rcCqtuP4S8FWRX74PGUvg+PnBqLNAIi OM7KaY0l4ep0U2crJqPBDnDnc/16og4esog0Co2NoXnH1tlBf+F/OXVIp/Px4Gmgwe JQLPAnw8c/6qA== Date: Wed, 22 Mar 2023 17:00:49 +0200 From: Mike Rapoport To: Vlastimil Babka Cc: Andrew Morton , David Hildenbrand , Doug Berger , Matthew Wilcox , Mel Gorman , Michal Hocko , Thomas Bogendoerfer , linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v2 04/14] mm: handle hashdist initialization in mm/mm_init.c Message-ID: References: <20230321170513.2401534-1-rppt@kernel.org> <20230321170513.2401534-5-rppt@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org On Wed, Mar 22, 2023 at 03:49:24PM +0100, Vlastimil Babka wrote: > On 3/21/23 18:05, Mike Rapoport wrote: > > From: "Mike Rapoport (IBM)" > > > > The hashdist variable must be initialized before the first call to > > alloc_large_system_hash() and free_area_init() looks like a better place > > for it than page_alloc_init(). > > > > Move hashdist handling to mm/mm_init.c > > > > Signed-off-by: Mike Rapoport (IBM) > > Acked-by: David Hildenbrand > > Reviewed-by: Vlastimil Babka > > Looks like this will move the fixup_hashdist() call earlier, but can't > result in seeing less N_MEMORY nodes than before, right? hashdist must be set before the first call to alloc_large_system_hash() and after the nodes present at boot time are initialized, so setting it in the end of free_area_init() is Ok. > I wonder if the whole thing lacks hotplug support anyway, what if system > boots with one node and more are added later? Hmm. alloc_large_system_hash() is called really early even for !HASH_EARLY cases. Not sure it's feasible to redistribute the hashes allocated with it when new node is added. > > --- > > mm/mm_init.c | 22 ++++++++++++++++++++++ > > mm/page_alloc.c | 18 ------------------ > > 2 files changed, 22 insertions(+), 18 deletions(-) > > > > diff --git a/mm/mm_init.c b/mm/mm_init.c > > index 68d0187c7886..2e60c7186132 100644 > > --- a/mm/mm_init.c > > +++ b/mm/mm_init.c > > @@ -607,6 +607,25 @@ int __meminit early_pfn_to_nid(unsigned long pfn) > > > > return nid; > > } > > + > > +int hashdist = HASHDIST_DEFAULT; > > + > > +static int __init set_hashdist(char *str) > > +{ > > + if (!str) > > + return 0; > > + hashdist = simple_strtoul(str, &str, 0); > > + return 1; > > +} > > +__setup("hashdist=", set_hashdist); > > + > > +static inline void fixup_hashdist(void) > > +{ > > + if (num_node_state(N_MEMORY) == 1) > > + hashdist = 0; > > +} > > +#else > > +static inline void fixup_hashdist(void) {} > > #endif /* CONFIG_NUMA */ > > > > #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT > > @@ -1855,6 +1874,9 @@ void __init free_area_init(unsigned long *max_zone_pfn) > > } > > > > memmap_init(); > > + > > + /* disable hash distribution for systems with a single node */ > > + fixup_hashdist(); > > } > > > > /** > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > > index c56c147bdf27..ff6a2fff2880 100644 > > --- a/mm/page_alloc.c > > +++ b/mm/page_alloc.c > > @@ -6383,28 +6383,10 @@ static int page_alloc_cpu_online(unsigned int cpu) > > return 0; > > } > > > > -#ifdef CONFIG_NUMA > > -int hashdist = HASHDIST_DEFAULT; > > - > > -static int __init set_hashdist(char *str) > > -{ > > - if (!str) > > - return 0; > > - hashdist = simple_strtoul(str, &str, 0); > > - return 1; > > -} > > -__setup("hashdist=", set_hashdist); > > -#endif > > - > > void __init page_alloc_init(void) > > { > > int ret; > > > > -#ifdef CONFIG_NUMA > > - if (num_node_state(N_MEMORY) == 1) > > - hashdist = 0; > > -#endif > > - > > ret = cpuhp_setup_state_nocalls(CPUHP_PAGE_ALLOC, > > "mm/page_alloc:pcp", > > page_alloc_cpu_online, > -- Sincerely yours, Mike.