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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id B95CAC48BC1 for ; Tue, 13 Feb 2024 15:15:39 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2EA0B8D0011; Tue, 13 Feb 2024 10:15:39 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 273768D0001; Tue, 13 Feb 2024 10:15:39 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1144E8D0011; Tue, 13 Feb 2024 10:15:39 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id EEF3E8D0001 for ; Tue, 13 Feb 2024 10:15:38 -0500 (EST) Received: from smtpin25.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id BE09B1208A0 for ; Tue, 13 Feb 2024 15:15:38 +0000 (UTC) X-FDA: 81787129956.25.E7D62F0 Received: from out-172.mta0.migadu.com (out-172.mta0.migadu.com [91.218.175.172]) by imf01.hostedemail.com (Postfix) with ESMTP id 030C940026 for ; Tue, 13 Feb 2024 15:15:34 +0000 (UTC) Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=sJ5JlmaL; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf01.hostedemail.com: domain of gang.li@linux.dev designates 91.218.175.172 as permitted sender) smtp.mailfrom=gang.li@linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1707837335; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=XIaty3z7Z757dXnIxnECy1zx9DTTw+93Glqw9JJsdD4=; b=Al9cLyFIwGRnh96oqeOJwTWW3lAuzSsBXKvMJX2H4eFDUiogau4oROMpUHdtIw+4f5lz8X v7vcqkEnJAUSycN13lQtiHHN/0hhxHAHqcKWJ68ELsPuADx+BinU3uHK2ITWoRv0/Csqd2 ovurcKJRATF2IlHMs+NtgRaza4yHw4Y= ARC-Authentication-Results: i=1; imf01.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=sJ5JlmaL; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf01.hostedemail.com: domain of gang.li@linux.dev designates 91.218.175.172 as permitted sender) smtp.mailfrom=gang.li@linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1707837335; a=rsa-sha256; cv=none; b=n1i7jHGJsDJCQa72K8esnc/zwyodLWa/61XGAIbsUJyzi10Kec1eMAwYYcA4oOKJG6nmTj 6jT//goKk70wbAahnJDpK44qEvDJo//iEKy1Ivu0YSK2UdS+d3AEemxfhwCQwKTdsRVOZf Vnk0YakTnOBZCrYs12jcGZy/aYDZHIY= Message-ID: <146c8a41-8864-4cff-80ce-173812441844@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1707837332; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=XIaty3z7Z757dXnIxnECy1zx9DTTw+93Glqw9JJsdD4=; b=sJ5JlmaL7tdAo/xSpNwms2zr99C8iwBVaUDwvBf/vZDNDsjHwCo2mn+8g33o8Sao94rY3l r5n2gOh80IBhZOIHRueT6CWZGkeccf8jMd+PuI5tK9mSVHeUGqCSGtixoOkJw3FyR1ZHzS 27nL20e8f5C1njfJjabODJtMsato0Cg= Date: Tue, 13 Feb 2024 23:15:19 +0800 MIME-Version: 1.0 Subject: Re: [PATCH v1 1/2] padata: downgrade padata_do_multithreaded to serial execution for non-SMP To: Muchun Song , Andrew Morton , Steffen Klassert , Daniel Jordan , Jane Chu , "Paul E . McKenney" , Randy Dunlap , kernel test robot , Gang Li Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20240213111347.3189206-1-gang.li@linux.dev> <20240213111347.3189206-2-gang.li@linux.dev> <89b3bee3-5ee3-4b75-99e3-881b759e79de@linux.dev> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Gang Li In-Reply-To: <89b3bee3-5ee3-4b75-99e3-881b759e79de@linux.dev> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Queue-Id: 030C940026 X-Rspam-User: X-Rspamd-Server: rspam04 X-Stat-Signature: xwctebx4i6u7y5mhm3nthtntma784crj X-HE-Tag: 1707837334-324781 X-HE-Meta: U2FsdGVkX1/IaonM55V43t3JasQK+w2QW6ilIdC2VIE6zCn51fyppSaagU6R/CutL+RXrHaKNK1o8jJvW9zCpk7+szL6FwOTay+Z+NmyUrvTI1+GY6q7sMLPEJuwvzL3WJZ/T82eOK7panQjm7cRFB6yImXZdUK5YilESrFLPf9E+l86nyHwJVQuHCfUGG8mnhywCsmMmUgNVkJ/KJHiQexJ/qAosrk9HzgBzN0ilbttDc57XxEf92QfQ6d6jiknG0gmB2pmmVWwf41Uda9DpZ43NSYQiVeXr7Rwhcaj55WG+1V/ZyZSal3i6YaumLVnx1etZFQ+IrsFlQDdWddiPyewOoErrEDZNOxBLt5I52aHCpgkvAFxKUmHvSMJmxmGANUfXVT6Kaz3bVi/bFSWISdLogfCqGhXSmAPwJgl2afMGhlIX+9IPBnyfmyTKUDLwhrxTst/1ftYTJu5dOTh3HIh0/UKEHVwrlUPOHaTn2vig2AEFdbd59/tv1aQ/BubfDcNgGAFmcY9Gp63CF03JQIu3EyFkJpf40vPG4o2zy54ZDNcp99OZZaMZ9ec0yqTAfldbzd8TE54ZAV/E59J6jRAhB8EGDHe/zbjEHVzO+lUwB+z0cM2c6gMj7aJScOr/tTcehraTHGHWic/tFDf3oTeC1y5Q5Ktakxz8/VUxLADe3/OwwTSdXQTxp8YbDmgt0eOPRjXtXzNI+85Oblsj/iGmyV/WBvfYx7ztm+jdVvZVpa0av3aFJ/MptqXXgvGjdjwymyQAqhYAVG9oIWBe2MTsSLgZqDxIBmsbIVXlNKAwLMhzClZZQ+yV8987kN149hjiOUf7dbgA8C1l5QDnnD5lN5wYZWoFyrFS4QqVdmPNHpL4zlroOsV4mcBd/FxrRdYlAH+enCMJPtCrZgLyC+BrsA7UnT0AwQgHbuuQ4r1loH4SdVh3MYuV1gv1+6ETulnhfM+WsyVHeSQzCa BOcZOc0i kcSLl0gi1S2CszCW0f9axzyIE9BWxOG5/n0CoZ0aD9K5KqMTOMugUbDc3A6HirXdeNcJBzOi41UIW2h43SURHD77122NCNX5A41Y1p4I5kuDfO5EpPxOG/E4r/BAZSBPKoxvbjrw8+23ZbGTMa5rv2bH4ydPV3Zj+DqV7MfdvCU2/LcLyBt5z/1hrcR9HjAtXkSGnZ2JPAcuzrL91K0KMmN0/YzNaHIY9E5Oyfqc6v50hcM3YnzzOT+LOSTSrJrFFzQ/4fuVc4JwtKrnYqnC6BA+5VO3SuOysXxMBhoNPDD0aqxEn0MCKkxZi3/Gk/yr0FYbiYxb1EdSPpHY= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2024/2/13 22:52, Muchun Song wrote: > On 2024/2/13 19:13, Gang Li wrote: >> Randy Dunlap and kernel test robot reported a warning: >> >> ``` >> WARNING: unmet direct dependencies detected for PADATA >>    Depends on [n]: SMP [=n] >>    Selected by [y]: >>    - HUGETLBFS [=y] && (X86 [=y] || SPARC64 || ARCH_SUPPORTS_HUGETLBFS >> [=n] || BROKEN [=n]) && (SYSFS [=y] || SYSCTL [=n]) >> ``` >> >> hugetlb parallelization depends on PADATA, and PADATA depends on SMP. >> >> PADATA consists of two distinct functionality: One part is >> padata_do_multithreaded which disregards order and simply divides >> tasks into several groups for parallel execution. Hugetlb >> init parallelization depends on padata_do_multithreaded. >> >> The other part is composed of a set of APIs that, while handling data in >> an out-of-order parallel manner, can eventually return the data with >> ordered sequence. Currently Only `crypto/pcrypt.c` use them. >> >> All users of PADATA of non-SMP case currently only use >> padata_do_multithreaded. It is easy to implement a serial one in >> include/linux/padata.h. And it is not necessary to implement another >> functionality unless the only user of crypto/pcrypt.c does not depend on >> SMP in the future. >> >> Fixes: a2cefb08be66 ("hugetlb: have CONFIG_HUGETLBFS select >> CONFIG_PADATA") >> Reported-by: Randy Dunlap >> Closes: >> https://lore.kernel.org/lkml/ec5dc528-2c3c-4444-9e88-d2c48395b433@infradead.org/ >> Reported-by: kernel test robot >> Closes: >> https://lore.kernel.org/oe-kbuild-all/202402020454.6EPkP1hi-lkp@intel.com/ >> Signed-off-by: Gang Li >> --- >>   fs/Kconfig             |  2 +- >>   include/linux/padata.h | 13 +++++++++---- >>   2 files changed, 10 insertions(+), 5 deletions(-) >> >> diff --git a/fs/Kconfig b/fs/Kconfig >> index 4a51331f172e5..7963939592d70 100644 >> --- a/fs/Kconfig >> +++ b/fs/Kconfig >> @@ -261,7 +261,7 @@ menuconfig HUGETLBFS >>       depends on X86 || SPARC64 || ARCH_SUPPORTS_HUGETLBFS || BROKEN >>       depends on (SYSFS || SYSCTL) >>       select MEMFD_CREATE >> -    select PADATA >> +    select PADATA if SMP > > I'd like to drop this dependence since HugeTLB does not depend > on PADATA anymore. If some users take care about the kernel > image size, it also can disable PADATA individually. > Only CRYPTO_PCRYPT, HUGETLBFS and DEFERRED_STRUCT_PAGE_INIT select PADATA. If drop this dependence, hugetlb init parallelization may not work at all. Maybe we can set PADATA enabled on default? >>       help >>         hugetlbfs is a filesystem backing for HugeTLB pages, based on >>         ramfs. For architectures that support it, say Y here and read >> diff --git a/include/linux/padata.h b/include/linux/padata.h >> index 8f418711351bc..7b84eb7d73e7f 100644 >> --- a/include/linux/padata.h >> +++ b/include/linux/padata.h >> @@ -180,10 +180,6 @@ struct padata_instance { >>   #ifdef CONFIG_PADATA >>   extern void __init padata_init(void); >> -#else >> -static inline void __init padata_init(void) {} >> -#endif >> - >>   extern struct padata_instance *padata_alloc(const char *name); >>   extern void padata_free(struct padata_instance *pinst); >>   extern struct padata_shell *padata_alloc_shell(struct >> padata_instance *pinst); >> @@ -194,4 +190,13 @@ extern void padata_do_serial(struct padata_priv >> *padata); >>   extern void __init padata_do_multithreaded(struct padata_mt_job *job); >>   extern int padata_set_cpumask(struct padata_instance *pinst, int >> cpumask_type, >>                     cpumask_var_t cpumask); >> +#else >> +static inline void __init padata_init(void) {} >> +static inline void __init padata_do_multithreaded(struct >> padata_mt_job *job) >> +{ >> +    if (job->size) > > I think we could drop this check, at least now there is no users will > pass a zero of ->size to this function, and even if someone does in the > future, I think it is really a corner case, it is unnecessary to optimize > it and ->thread_fn is supporsed to handle case of zero size if it dose > pass a zero size. > > Thanks. > >> +        job->thread_fn(job->start, job->start + job->size, job->fn_arg); >> +} >> +#endif >> + >>   #endif >