From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f46.google.com (mail-pj1-f46.google.com [209.85.216.46]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1250D5CAD for ; Wed, 16 Nov 2022 12:49:41 +0000 (UTC) Received: by mail-pj1-f46.google.com with SMTP id w3-20020a17090a460300b00218524e8877so2545349pjg.1 for ; Wed, 16 Nov 2022 04:49:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=iDgEMkQKaoP0nhYxIU0Ohu7ZkC7Py1Uf1KZ5o6BJIpE=; b=cSFNYKR4V0VfYoA8CgFHjvGHHYmkUa1gf2ZJHnciB89Sa8TItaXxWSUVX/AVZO68qM oWk7S9MK3rWvdhrf6TQcxCpYT4ZD4ROGOi7Ab1ZaH8RJhYKhBUS/u4KJ9oyNsJvlNOcW zGo3wP7Wto5CTAPNTCDchCjDaFFjEWkVqccV36B4jDVMoAWB9RsDTpwEe+9MERdstdHE v/+8evhd/FzM7JmBoW1QHDxKTfgV4Q4LeFonSTQSg5GK4yrDTYkkabLpzghfcXoOSe2V 7zQQQUuHg8sg7kCPsSQPiitfvWgkuafdx7legzqPHNENa/SOWuuAAV+BA/3c2VVLyHwm FjOA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=iDgEMkQKaoP0nhYxIU0Ohu7ZkC7Py1Uf1KZ5o6BJIpE=; b=K2i3TeoTpVnEc8tsHPhUfcJyIfFnpqArIUt16SEs3BulSkiUB0svTH/zm3/d8ZVefc azlESHCnGSC9w/OnI5/+1JVAuy9cDqICXqOWke28hc3VHV9qqbXwxVbEc+tygnO3RRnt 9Yy5G9znxwOMeazb32k11uTb2H5pV+PyNKX6a+bzyU5es382qcc7MLwX0iZhclFV2ucF 2gCl9DFqm4Gpz26Wpc6ibRjiyNQh90z2iKKL/oh4ak1W4rx7WrDHU6InEyCeybA7T7Qo 5CE/CoVvgkGhqY5u+ECRocSoxije+2mF/t9OPdxjt456sLoFepMG6i8qakl6q6yj5/JR aSmA== X-Gm-Message-State: ANoB5plY19tbaeNEAfALzQ2rMh8j33qj9ba08uUDbyWtnRA1As3cy0zp IDF+eFfa5ZykSnlmspZH8lQ= X-Google-Smtp-Source: AA0mqf4LlK5FsbuLksuV7PPLsN3QTZCjVycQLJFPpkJlNvfNGAyWVsHlNefE1gf3jYFNJ+V3vmzG+w== X-Received: by 2002:a17:90a:718a:b0:205:a550:e529 with SMTP id i10-20020a17090a718a00b00205a550e529mr3663353pjk.25.1668602981324; Wed, 16 Nov 2022 04:49:41 -0800 (PST) Received: from hyeyoo ([114.29.91.56]) by smtp.gmail.com with ESMTPSA id b5-20020a170903228500b00186881e1feasm12208114plh.112.2022.11.16.04.49.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Nov 2022 04:49:40 -0800 (PST) Date: Wed, 16 Nov 2022 21:49:35 +0900 From: Hyeonggon Yoo <42.hyeyoo@gmail.com> To: Dennis Zhou Cc: Baoquan He , Vlastimil Babka , kernel test robot , oe-kbuild-all@lists.linux.dev, Linux Memory Management List Subject: Re: [linux-next:master 5002/7443] include/linux/compiler_types.h:357:45: error: call to '__compiletime_assert_474' declared with attribute error: BUILD_BUG_ON failed: PERCPU_DYNAMIC_EARLY_SIZE < NR_KMALLOC_TYPES * KMALLOC_SHIFT_HIGH * sizeof(struct kmem_cache_cpu) Message-ID: References: <202211120436.HzD1i2yQ-lkp@intel.com> Precedence: bulk X-Mailing-List: oe-kbuild-all@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Nov 15, 2022 at 12:00:16PM -0800, Dennis Zhou wrote: > On Tue, Nov 15, 2022 at 05:08:52PM +0800, Baoquan He wrote: > > Hi Dennis, > > > > On 11/14/22 at 08:13pm, Dennis Zhou wrote: > > > Hi Vlastimil & Baoquan, > > > > > > On Mon, Nov 14, 2022 at 06:58:13PM +0100, Vlastimil Babka wrote: > > > > On 11/14/22 08:44, Baoquan He wrote: > > > > > Hi, > > > > > > > > > > I reproduced the build failure according to lkp report and made a patch > > > > > as below to fix it. > > > > > > > > > > From dae7dd9705015ce36db757e88c78802584f949b1 Mon Sep 17 00:00:00 2001 > > > > > From: Baoquan He > > > > > Date: Sun, 13 Nov 2022 18:08:27 +0800 > > > > > Subject: [PATCH] percpu: adjust the value of PERCPU_DYNAMIC_EARLY_SIZE > > > > > Content-type: text/plain > > > > > > > > > > LKP reported a build failure as below on the patch "mm/slub, percpu: > > > > > correct the calculation of early percpu allocation size" > > > > > > > > Since I have that patch in slab.git exposed to -next, should I take this fix > > > > too, to make things simpler? Dennis? > > > > > > > > > > I don't have any problems with you running a fix, but I'm not quite sure > > > this is the right fix. Though this might cause a trivial merge conflict > > > with: d667c94962c1 ("mm/percpu: remove unused PERCPU_DYNAMIC_EARLY_SLOTS") > > > in my percpu#for-6.2 branch. > > > > > > If I'm understanding this correctly, slub requires additional percpu > > > memory due to the use of 64k pages. By increasing > > > PERCPU_DYNAMIC_EARLY_SIZE, we solve the problem for 64k page users, but > > > require a few unnecessary pages that can bloat the size of subsequent > > > percpu chunks. Though, I'm not sure if that's an issue today for > > > embedded devices. > > > > Thanks for looking into this. > > > > I guess you are talking about PERCPU_DYNAMIC_EARLY_SIZE will impact the > > first dynamic chunk size of page first chunk, because the embed first > > chunk will take PERCPU_DYNAMIC_RESERVE. And the impact is done in below > > max() invacation. > > > > static struct pcpu_alloc_info * __init __flatten pcpu_build_alloc_info( > > size_t reserved_size, size_t dyn_size, > > size_t atom_size, > > pcpu_fc_cpu_distance_fn_t cpu_distance_fn) > > { > > ...... > > /* calculate size_sum and ensure dyn_size is enough for early alloc */ > > size_sum = PFN_ALIGN(static_size + reserved_size + > > max_t(size_t, dyn_size, PERCPU_DYNAMIC_EARLY_SIZE)); > > ...... > > } > > > > > > > > I think adding parity to PERCPU_DYNAMIC_EARLY_SIZE with > > > PERCPU_DYNAMIC_RESERVE is defined by BITS_PER_LONG is a safer option > > > here. A small TODO item would be to make PERCPU_DYNAMIC_RESERVE be a + > > > value instead of a max() with PERCPU_DYNAMIC_EARLY_SIZE. > > > > Hmm, the below change may not take power arch into account. Please > > check arch/powerpc/include/asm/page.h, seems the 32bit ppc could have > > 256K pages too. Adding PERCPU_DYNAMIC_EARLY_SIZE to 20K may cost extra > > memory during boot. But th left space of 1st dynamic chunk will join > > the later percpu dynamic allocation, it's not wasted, right? > > > > Not sure if I got your point. > > > > > > Ah, I'm not familiar with all the PAGE_SIZE and word length > combinations. > > The first chunk is smaller in the embedded case with the assumption that > static percpu variables are highly accessed along with the limited > initial allocations. While adding an additional 8KB is not the biggest > deal to the first chunk, this can cause the unit_size for subsequent > chunks to be larger. For example, x86 unit size jumps in powers of 2 due > to alignment and packing against an allocation size of 2MB. So if we're > at say 60KB for the first chunk, subsequent chunks could be 64KB. But > adding 8KB, we'd go from 60KB -> 68KB and a chunk size of 64KB -> 128KB. > > If not `BITS_PER_LONG >32`, we could do `PAGE_SHIFT > 12`. You may want to use #ifdef CONFIG_SLUB_STATS. That's primary reason that makes SLUB require bigger early percpu memory area. > > Thanks, > Dennis > > > > > > > --- > > > diff --git a/include/linux/percpu.h b/include/linux/percpu.h > > > index f1ec5ad1351c..22ce3271eed2 100644 > > > --- a/include/linux/percpu.h > > > +++ b/include/linux/percpu.h > > > @@ -42,7 +42,11 @@ > > > * larger than PERCPU_DYNAMIC_EARLY_SIZE. > > > */ > > > #define PERCPU_DYNAMIC_EARLY_SLOTS 128 > > > +#if BITS_PER_LONG > 32 > > > +#define PERCPU_DYNAMIC_EARLY_SIZE (20 << 10) > > > +#else > > > #define PERCPU_DYNAMIC_EARLY_SIZE (12 << 10) > > > +#endif > > > > > > /* > > > * PERCPU_DYNAMIC_RESERVE indicates the amount of free area to piggy > > > > > > > -- Thanks, Hyeonggon