From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D8EFE6AB8; Wed, 29 May 2024 05:32:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716960740; cv=none; b=ewYPDZylUz8Nw1JrHJoSMfHR1qsu6SVXuNaLPl2KCPIC0Scn/vwt6J664LPDgyTXvPWnBulBP/lV7uQdiq1AogdEWu5D5orbB8gJ2WsVx4Z6l5UrWj8VVrAR4js6cgrJMmxcnOlsZttDa8QyqbwSMuuFKALpvmqCvc7s/0Dym80= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716960740; c=relaxed/simple; bh=aBznwI196mCXdIjypa7AmSwqqkGS5EsYJK31pzgSYXA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Anw3k28OxNx+aKzId/IrGt7MpT+Z1/F11WZes45Zq7ao1//Qp5N6AgMOOqD4mBUAMdl5ZrE23wojPI7cbMsx099f5fO9njEODUxyTXVumreJq+NECsE23rRaAkMfNWJAOz25BY7UZ/vi7Hwajacd0h8MTGq1m8CusmrMT8zcuRE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=LeEZBqXs; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="LeEZBqXs" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5A7FFC2BD10; Wed, 29 May 2024 05:32:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1716960739; bh=aBznwI196mCXdIjypa7AmSwqqkGS5EsYJK31pzgSYXA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=LeEZBqXsaFwHKqq22xYJkq1anme+3hC9y4dtkgVlEK8L0HpFZWUwdSNmDY9Dkw6NW jmYzLhjePapm2TqQULKLIdowZXJ5+4rkJdUNI6remV3ooCQ/tnpDnrCOCjxWLhxWUa wnIWzdQOEkuJE9hEeHvETExo8PPpuO700JnCabxsCN0WeaNU6RsdbqNH06C052cUbz pcYHVG/nEm6xkBGENDwx7i0hAa/WwhPnHmaFiBu7FRjnOtZfVtTI158ewx8yBQdXzA 2PEUKqEd3KrOUZjq6zO2DU3cPgp149y+59wWRzK4VAWqxaA4LAIaxHdvKkBqK7f830 Q8mHay2aWjJlg== Date: Wed, 29 May 2024 08:30:27 +0300 From: Mike Rapoport To: Eric Chanudet Cc: Dave Hansen , Andy Lutomirski , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Andrew Morton , Baoquan He , Michael Ellerman , Nick Piggin , x86@kernel.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH v3] mm/mm_init: use node's number of cpus in deferred_page_init_max_threads Message-ID: References: <20240528185455.643227-4-echanude@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240528185455.643227-4-echanude@redhat.com> On Tue, May 28, 2024 at 02:54:58PM -0400, Eric Chanudet wrote: > When DEFERRED_STRUCT_PAGE_INIT=y, use a node's cpu count as maximum > thread count for the deferred initialization of struct pages via padata. > This should result in shorter boot times for these configurations by > going through page_alloc_init_late() faster as systems tend not to be > under heavy load that early in the bootstrap. > > Only x86_64 does that now. Make it archs agnostic when > DEFERRED_STRUCT_PAGE_INIT is set. With the default defconfigs, that > includes powerpc and s390. > > It used to be so before offering archs to override the function for > tuning with commit ecd096506922 ("mm: make deferred init's max threads > arch-specific"). > > Setting DEFERRED_STRUCT_PAGE_INIT and testing on a few arm64 platforms > shows faster deferred_init_memmap completions: > | | x13s | SA8775p-ride | Ampere R137-P31 | Ampere HR330 | > | | Metal, 32GB | VM, 36GB | VM, 58GB | Metal, 128GB | > | | 8cpus | 8cpus | 8cpus | 32cpus | > |---------|-------------|--------------|-----------------|--------------| > | threads | ms (%) | ms (%) | ms (%) | ms (%) | > |---------|-------------|--------------|-----------------|--------------| > | 1 | 108 (0%) | 72 (0%) | 224 (0%) | 324 (0%) | > | cpus | 24 (-77%) | 36 (-50%) | 40 (-82%) | 56 (-82%) | > > Michael Ellerman on a powerpc machine (1TB, 40 cores, 4KB pages) reports > faster deferred_init_memmap from 210-240ms to 90-110ms between nodes. > > Signed-off-by: Eric Chanudet > Tested-by: Michael Ellerman (powerpc) Acked-by: Mike Rapoport (IBM) > --- > - v1: https://lore.kernel.org/linux-arm-kernel/20240520231555.395979-5-echanude@redhat.com > - Changes since v1: > - Make the generic function return the number of cpus of the node as > max threads limit instead overriding it for arm64. > - Drop Baoquan He's R-b on v1 since the logic changed. > - Add CCs according to patch changes (ppc and s390 set > DEFERRED_STRUCT_PAGE_INIT by default). > > - v2: https://lore.kernel.org/linux-arm-kernel/20240522203758.626932-4-echanude@redhat.com/ > - Changes since v2: > - deferred_page_init_max_threads returns unsigned and use max instead > of max_t. > - Make deferred_page_init_max_threads static since there are no more > override. > - Rephrase description. > - Add T-b and report from Michael Ellerman. > > arch/x86/mm/init_64.c | 12 ------------ > include/linux/memblock.h | 2 -- > mm/mm_init.c | 5 ++--- > 3 files changed, 2 insertions(+), 17 deletions(-) > > diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c > index 7e177856ee4f..adec42928ec1 100644 > --- a/arch/x86/mm/init_64.c > +++ b/arch/x86/mm/init_64.c > @@ -1354,18 +1354,6 @@ void __init mem_init(void) > preallocate_vmalloc_pages(); > } > > -#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT > -int __init deferred_page_init_max_threads(const struct cpumask *node_cpumask) > -{ > - /* > - * More CPUs always led to greater speedups on tested systems, up to > - * all the nodes' CPUs. Use all since the system is otherwise idle > - * now. > - */ > - return max_t(int, cpumask_weight(node_cpumask), 1); > -} > -#endif > - > int kernel_set_to_readonly; > > void mark_rodata_ro(void) > diff --git a/include/linux/memblock.h b/include/linux/memblock.h > index e2082240586d..40c62aca36ec 100644 > --- a/include/linux/memblock.h > +++ b/include/linux/memblock.h > @@ -335,8 +335,6 @@ void __next_mem_pfn_range_in_zone(u64 *idx, struct zone *zone, > for (; i != U64_MAX; \ > __next_mem_pfn_range_in_zone(&i, zone, p_start, p_end)) > > -int __init deferred_page_init_max_threads(const struct cpumask *node_cpumask); > - > #endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */ > > /** > diff --git a/mm/mm_init.c b/mm/mm_init.c > index f72b852bd5b8..acfeba508796 100644 > --- a/mm/mm_init.c > +++ b/mm/mm_init.c > @@ -2122,11 +2122,10 @@ deferred_init_memmap_chunk(unsigned long start_pfn, unsigned long end_pfn, > } > } > > -/* An arch may override for more concurrency. */ > -__weak int __init > +static unsigned int __init > deferred_page_init_max_threads(const struct cpumask *node_cpumask) > { > - return 1; > + return max(cpumask_weight(node_cpumask), 1U); > } > > /* Initialise remaining memory on a node */ > -- > 2.44.0 > -- Sincerely yours, Mike.