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=-11.4 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 6D6F3C388F7 for ; Thu, 22 Oct 2020 16:52:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 14CA92168B for ; Thu, 22 Oct 2020 16:52:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2902091AbgJVQwU (ORCPT ); Thu, 22 Oct 2020 12:52:20 -0400 Received: from mx2.suse.de ([195.135.220.15]:35334 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2898218AbgJVQwU (ORCPT ); Thu, 22 Oct 2020 12:52:20 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id B56BCADEC; Thu, 22 Oct 2020 16:52:18 +0000 (UTC) Subject: Re: [PATCH v2] mm,thp,shmem: limit shmem THP alloc gfp_mask To: Rik van Riel , Hugh Dickins Cc: Yu Xu , Andrew Morton , Mel Gorman , Andrea Arcangeli , Matthew Wilcox , linux-mm@kvack.org, kernel-team@fb.com, linux-kernel@vger.kernel.org References: <20201022124511.72448a5f@imladris.surriel.com> From: Vlastimil Babka Message-ID: <4f98ea59-a9df-de6d-1084-8a8867c20052@suse.cz> Date: Thu, 22 Oct 2020 18:52:18 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.3.2 MIME-Version: 1.0 In-Reply-To: <20201022124511.72448a5f@imladris.surriel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/22/20 6:45 PM, Rik van Riel wrote: > The allocation flags of anonymous transparent huge pages can be controlled > through the files in /sys/kernel/mm/transparent_hugepage/defrag, which can > help the system from getting bogged down in the page reclaim and compaction > code when many THPs are getting allocated simultaneously. > > However, the gfp_mask for shmem THP allocations were not limited by those > configuration settings, and some workloads ended up with all CPUs stuck > on the LRU lock in the page reclaim code, trying to allocate dozens of > THPs simultaneously. > > This patch applies the same configurated limitation of THPs to shmem > hugepage allocations, to prevent that from happening. > > This way a THP defrag setting of "never" or "defer+madvise" will result > in quick allocation failures without direct reclaim when no 2MB free > pages are available. > > Signed-off-by: Rik van Riel Acked-by: Vlastimil Babka > --- > v2: move gfp calculation to shmem_getpage_gfp as suggested by Yu Xu > > diff --git a/include/linux/gfp.h b/include/linux/gfp.h > index c603237e006c..0a5b164a26d9 100644 > --- a/include/linux/gfp.h > +++ b/include/linux/gfp.h > @@ -614,6 +614,8 @@ bool gfp_pfmemalloc_allowed(gfp_t gfp_mask); > extern void pm_restrict_gfp_mask(void); > extern void pm_restore_gfp_mask(void); > > +extern gfp_t alloc_hugepage_direct_gfpmask(struct vm_area_struct *vma); > + > #ifdef CONFIG_PM_SLEEP > extern bool pm_suspended_storage(void); > #else > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index 9474dbc150ed..9b08ce5cc387 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -649,7 +649,7 @@ static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf, > * available > * never: never stall for any thp allocation > */ > -static inline gfp_t alloc_hugepage_direct_gfpmask(struct vm_area_struct *vma) > +gfp_t alloc_hugepage_direct_gfpmask(struct vm_area_struct *vma) > { > const bool vma_madvised = !!(vma->vm_flags & VM_HUGEPAGE); > > diff --git a/mm/shmem.c b/mm/shmem.c > index 537c137698f8..9710b9df91e9 100644 > --- a/mm/shmem.c > +++ b/mm/shmem.c > @@ -1545,8 +1545,8 @@ static struct page *shmem_alloc_hugepage(gfp_t gfp, > return NULL; > > shmem_pseudo_vma_init(&pvma, info, hindex); > - page = alloc_pages_vma(gfp | __GFP_COMP | __GFP_NORETRY | __GFP_NOWARN, > - HPAGE_PMD_ORDER, &pvma, 0, numa_node_id(), true); > + page = alloc_pages_vma(gfp, HPAGE_PMD_ORDER, &pvma, 0, numa_node_id(), > + true); > shmem_pseudo_vma_destroy(&pvma); > if (page) > prep_transhuge_page(page); > @@ -1802,6 +1802,7 @@ static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, > struct page *page; > enum sgp_type sgp_huge = sgp; > pgoff_t hindex = index; > + gfp_t huge_gfp; > int error; > int once = 0; > int alloced = 0; > @@ -1887,7 +1888,8 @@ static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, > } > > alloc_huge: > - page = shmem_alloc_and_acct_page(gfp, inode, index, true); > + huge_gfp = alloc_hugepage_direct_gfpmask(vma); > + page = shmem_alloc_and_acct_page(huge_gfp, inode, index, true); > if (IS_ERR(page)) { > alloc_nohuge: > page = shmem_alloc_and_acct_page(gfp, inode, >