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=-9.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 6ED46C388F9 for ; Sat, 24 Oct 2020 02:09:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B47C02176B for ; Sat, 24 Oct 2020 02:09:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="AD2j7Mmh" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758901AbgJXCJe (ORCPT ); Fri, 23 Oct 2020 22:09:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53664 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756462AbgJXCJe (ORCPT ); Fri, 23 Oct 2020 22:09:34 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 31DD4C0613CE for ; Fri, 23 Oct 2020 19:09:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=RzNHOCYQ4xJRdKe5TcT6iQTXGCT7yybZ343knApl/AA=; b=AD2j7MmhRRxAwLhKomRXF3tlDJ CpvodUK4U4D9S5o2yX+9N2c0hZ2izTgcwzrAIjBEAt0YN0gL97/UUpWt8S8rSt6RWuRCQHww86g3V Z0RHtsOuXlrZ272JVhhtIYePWYhRzF5DMaGyLn5m9MOdb2mT1oWDtrGPHK3Z9daemIXsrPaP6+UHo 8G2oLQbRBTYUlldc29uenjMaJA3n+2AuZvkdfPcH0i2Hg/HoCsJuFFT7NBFdzYd8PsHYTroJu28sP 6hmBhaciBE0oJ2fHDNTXCpmCp8/NCF4NUgoDa7T+IZLFuCrdbVuDA3XZVwfb9355G6wygXNf3s9Xj s+PluDkQ==; Received: from willy by casper.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1kW8zi-00086a-3F; Sat, 24 Oct 2020 02:09:22 +0000 Date: Sat, 24 Oct 2020 03:09:22 +0100 From: Matthew Wilcox To: Rik van Riel Cc: Hugh Dickins , Yu Xu , Andrew Morton , Mel Gorman , Andrea Arcangeli , linux-kernel@vger.kernel.org, kernel-team@fb.com, linux-mm@kvack.org, Vlastimil Babka , Michal Hocko Subject: Re: [PATCH v4] mm,thp,shmem: limit shmem THP alloc gfp_mask Message-ID: <20201024020922.GH20115@casper.infradead.org> References: <20201023204804.3f8d19c1@imladris.surriel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201023204804.3f8d19c1@imladris.surriel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 23, 2020 at 08:48:04PM -0400, 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. > > With this patch applied, THP allocations for tmpfs will be a little > more aggressive than today for files mmapped with MADV_HUGEPAGE, > and a little less aggressive for files that are not mmapped or > mapped without that flag. How about this code path though? shmem_get_pages() [ in i915 ] shmem_read_mapping_page_gfp(__GFP_NORETRY | __GFP_NOWARN) shmem_getpage_gfp() shmem_alloc_and_acct_page() shmem_alloc_hugepage() I feel like the NORETRY from i915 should override whatever is set in sysfs for anon THPs. What do others think? > Signed-off-by: Rik van Riel > --- > v4: rename alloc_hugepage_direct_gfpmask to vma_thp_gfp_mask (Matthew Wilcox) > v3: fix NULL vma issue spotted by Hugh Dickins & tested > 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..c7615c9ba03c 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 vma_thp_gfp_mask(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..c5d03b2f2f2f 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -649,9 +649,9 @@ 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 vma_thp_gfp_mask(struct vm_area_struct *vma) > { > - const bool vma_madvised = !!(vma->vm_flags & VM_HUGEPAGE); > + const bool vma_madvised = vma && (vma->vm_flags & VM_HUGEPAGE); > > /* Always do synchronous compaction */ > if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) > @@ -744,7 +744,7 @@ vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf) > pte_free(vma->vm_mm, pgtable); > return ret; > } > - gfp = alloc_hugepage_direct_gfpmask(vma); > + gfp = vma_thp_gfp_mask(vma); > page = alloc_hugepage_vma(gfp, vma, haddr, HPAGE_PMD_ORDER); > if (unlikely(!page)) { > count_vm_event(THP_FAULT_FALLBACK); > diff --git a/mm/shmem.c b/mm/shmem.c > index 537c137698f8..6c3cb192a88d 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 = vma_thp_gfp_mask(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,