From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 838225339F for ; Wed, 11 Sep 2024 09:27:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726046852; cv=none; b=ppG5cseqwuvzLgwiitglWcOGD6BbPQC/pIs9TmfyCRGyxacSZkW4UcKCyjZ2BynStt++kLHCmqOS3900AKg3jL906ZN0wyMhUj+PGbvxhypMElkjwQ2zc7nDSB60CkTqT0Zd1xLLYICLasds6y33JJwfRYSNvgUi2GuJTF0pgsI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726046852; c=relaxed/simple; bh=5nNp16CeC3Jnh/g80+hofqDJQcRTQmF83vE06HozTaU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=oe72zzCEytFEL4Af6L/Fxg7DEcAE9SrtZ7ATzT/a9O1Nm6cUeBHESJG95CFBmmLzzKYX0HdJWwIhrBMgbwpiU0N+jpJGUK4/0Ewx5727CK96TKRKpg8yCf/V82VUp9+vAcxSEXHnScaTNpYVwJ+nj2HhK898sp5ibeYq2PQQlYY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=eC2EuO+2; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="eC2EuO+2" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1726046849; 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:autocrypt:autocrypt; bh=R/GUWn+SGa4XRFyfz/TpXCrIn72ftmILC3/riPse6xQ=; b=eC2EuO+2hVqVLaZ+AQfP9AV9K4xlfZ4OMnn2XJoA3eJG1OqPqwmEbVUkkpJ++tK1LX3nm3 wbDff4FpY2ZQUJimSzZo+xf+sEK8Hm/YJwn6kUlEdPaVRel3QKXn/dwFVAPSZTK8LZAYJ8 rw5N8yqad/xIZa18T6QY0szogDc4Tiw= Received: from mail-wr1-f72.google.com (mail-wr1-f72.google.com [209.85.221.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-54-NMXQWliOOImEEEqOfPBq8g-1; Wed, 11 Sep 2024 05:27:28 -0400 X-MC-Unique: NMXQWliOOImEEEqOfPBq8g-1 Received: by mail-wr1-f72.google.com with SMTP id ffacd0b85a97d-3756212a589so4367377f8f.2 for ; Wed, 11 Sep 2024 02:27:28 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1726046847; x=1726651647; h=content-transfer-encoding:in-reply-to:organization:autocrypt :content-language:from:references:cc:to:subject:user-agent :mime-version:date:message-id:x-gm-message-state:from:to:cc:subject :date:message-id:reply-to; bh=R/GUWn+SGa4XRFyfz/TpXCrIn72ftmILC3/riPse6xQ=; b=LCW+Xx5gJq6Wmwsn9lSKGpO9b+SpuPtKTr4aMFbp/1Nf4d8kpVIl5Vt3mqsxQBhXVZ u+ZyT1U752sjelezHvZP2UP/ekw5IUsxVJ8Blx9wGwFEn4yEH5uU/GQsb01OdsKtOG+M mcIlfpfJzMo1eDsH4p0SbBxNelN11/NnZrW/yf0yWU5ATw7jFQs+sCgYaZr1Bc8N1esg 5BMT6VuHk4RIeEZbw0Pj/dlkEMbNLLWyN057fGFeUj+Ec58o6EsweTZrnO1YElvSyOJD Y7dnD6GZB34bNXPv1AHreM0mUlzCeuNvIWhD9jZuFT3d3sp4yQxr6QR7ulDdoeilBMrL YXpQ== X-Forwarded-Encrypted: i=1; AJvYcCWexdm7njtDvL4IWb5vyj0FbnUZzYmlb61YbJFCxOiJTjS/lJSRK7YzKdo9Llakhr6KQR8WQ8lBoUSNWYU=@vger.kernel.org X-Gm-Message-State: AOJu0YwkzHTOoBIJIPm3yjuWYXd1sUXcdts8rKmT8U8mWmDFYRoKH7uh is/lTzklhe0FmG1uSahBVobTcv4V/fBLsMVAW2AI6MOozpIePmm/CN9CRiiAAc5g5jjboyy41ZD oBluD50ezFXv3bblbz/VSxfUHfKFE997SRFzWf7JhhbGNOd911FHv+QW1rPr1lA== X-Received: by 2002:adf:ee8e:0:b0:374:c948:f4db with SMTP id ffacd0b85a97d-378922b6acemr10515016f8f.26.1726046846901; Wed, 11 Sep 2024 02:27:26 -0700 (PDT) X-Google-Smtp-Source: AGHT+IGDWipS+ccf93/Q0bM7IybEh17v7dD9fkq7xYbLCpvjB5awsqPm17rnk80P/e9cQ9lhxXIgMA== X-Received: by 2002:adf:ee8e:0:b0:374:c948:f4db with SMTP id ffacd0b85a97d-378922b6acemr10514947f8f.26.1726046845645; Wed, 11 Sep 2024 02:27:25 -0700 (PDT) Received: from ?IPV6:2003:cb:c70c:1e00:4443:eaa9:9f5d:1497? (p200300cbc70c1e004443eaa99f5d1497.dip0.t-ipconnect.de. [2003:cb:c70c:1e00:4443:eaa9:9f5d:1497]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-378956dbc28sm11013622f8f.91.2024.09.11.02.27.23 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 11 Sep 2024 02:27:24 -0700 (PDT) Message-ID: Date: Wed, 11 Sep 2024 11:27:23 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 1/2] mm: Abstract THP allocation To: Dev Jain , akpm@linux-foundation.org, willy@infradead.org, kirill.shutemov@linux.intel.com Cc: ryan.roberts@arm.com, anshuman.khandual@arm.com, catalin.marinas@arm.com, cl@gentwo.org, vbabka@suse.cz, mhocko@suse.com, apopple@nvidia.com, dave.hansen@linux.intel.com, will@kernel.org, baohua@kernel.org, jack@suse.cz, mark.rutland@arm.com, hughd@google.com, aneesh.kumar@kernel.org, yang@os.amperecomputing.com, peterx@redhat.com, ioworker0@gmail.com, jglisse@google.com, wangkefeng.wang@huawei.com, ziy@nvidia.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20240911065600.1002644-1-dev.jain@arm.com> <20240911065600.1002644-2-dev.jain@arm.com> From: David Hildenbrand Content-Language: en-US Autocrypt: addr=david@redhat.com; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZgEEwEIAEICGwMGCwkIBwMCBhUIAgkKCwQW AgMBAh4BAheAAhkBFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAl8Ox4kFCRKpKXgACgkQTd4Q 9wD/g1oHcA//a6Tj7SBNjFNM1iNhWUo1lxAja0lpSodSnB2g4FCZ4R61SBR4l/psBL73xktp rDHrx4aSpwkRP6Epu6mLvhlfjmkRG4OynJ5HG1gfv7RJJfnUdUM1z5kdS8JBrOhMJS2c/gPf wv1TGRq2XdMPnfY2o0CxRqpcLkx4vBODvJGl2mQyJF/gPepdDfcT8/PY9BJ7FL6Hrq1gnAo4 3Iv9qV0JiT2wmZciNyYQhmA1V6dyTRiQ4YAc31zOo2IM+xisPzeSHgw3ONY/XhYvfZ9r7W1l pNQdc2G+o4Di9NPFHQQhDw3YTRR1opJaTlRDzxYxzU6ZnUUBghxt9cwUWTpfCktkMZiPSDGd KgQBjnweV2jw9UOTxjb4LXqDjmSNkjDdQUOU69jGMUXgihvo4zhYcMX8F5gWdRtMR7DzW/YE BgVcyxNkMIXoY1aYj6npHYiNQesQlqjU6azjbH70/SXKM5tNRplgW8TNprMDuntdvV9wNkFs 9TyM02V5aWxFfI42+aivc4KEw69SE9KXwC7FSf5wXzuTot97N9Phj/Z3+jx443jo2NR34XgF 89cct7wJMjOF7bBefo0fPPZQuIma0Zym71cP61OP/i11ahNye6HGKfxGCOcs5wW9kRQEk8P9 M/k2wt3mt/fCQnuP/mWutNPt95w9wSsUyATLmtNrwccz63XOwU0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAHCwXwEGAEIACYCGwwWIQQb2cqtc1xMOkYN/MpN3hD3 AP+DWgUCXw7HsgUJEqkpoQAKCRBN3hD3AP+DWrrpD/4qS3dyVRxDcDHIlmguXjC1Q5tZTwNB boaBTPHSy/Nksu0eY7x6HfQJ3xajVH32Ms6t1trDQmPx2iP5+7iDsb7OKAb5eOS8h+BEBDeq 3ecsQDv0fFJOA9ag5O3LLNk+3x3q7e0uo06XMaY7UHS341ozXUUI7wC7iKfoUTv03iO9El5f XpNMx/YrIMduZ2+nd9Di7o5+KIwlb2mAB9sTNHdMrXesX8eBL6T9b+MZJk+mZuPxKNVfEQMQ a5SxUEADIPQTPNvBewdeI80yeOCrN+Zzwy/Mrx9EPeu59Y5vSJOx/z6OUImD/GhX7Xvkt3kq Er5KTrJz3++B6SH9pum9PuoE/k+nntJkNMmQpR4MCBaV/J9gIOPGodDKnjdng+mXliF3Ptu6 3oxc2RCyGzTlxyMwuc2U5Q7KtUNTdDe8T0uE+9b8BLMVQDDfJjqY0VVqSUwImzTDLX9S4g/8 kC4HRcclk8hpyhY2jKGluZO0awwTIMgVEzmTyBphDg/Gx7dZU1Xf8HFuE+UZ5UDHDTnwgv7E th6RC9+WrhDNspZ9fJjKWRbveQgUFCpe1sa77LAw+XFrKmBHXp9ZVIe90RMe2tRL06BGiRZr jPrnvUsUUsjRoRNJjKKA/REq+sAnhkNPPZ/NNMjaZ5b8Tovi8C0tmxiCHaQYqj7G2rgnT0kt WNyWQQ== Organization: Red Hat In-Reply-To: <20240911065600.1002644-2-dev.jain@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 11.09.24 08:55, Dev Jain wrote: > In preparation for the second patch, abstract away the THP allocation > logic present in the create_huge_pmd() path, which corresponds to the > faulting case when no page is present. > > There should be no functional change as a result of applying > this patch. > Hi, > Signed-off-by: Dev Jain > --- > mm/huge_memory.c | 110 +++++++++++++++++++++++++++++------------------ > 1 file changed, 67 insertions(+), 43 deletions(-) > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index 67c86a5d64a6..b96a1ff2bf40 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -943,47 +943,88 @@ unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, > } > EXPORT_SYMBOL_GPL(thp_get_unmapped_area); > > -static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf, > - struct page *page, gfp_t gfp) > +static struct folio *pmd_thp_fault_alloc(gfp_t gfp, struct vm_area_struct *vma, > + unsigned long haddr, unsigned long addr) I suggest calling this something like "vma_alloc_anon_folio_pmd()"? Then it's more consistent with vma_alloc_folio(). Also, likely we should just only pass in "addr" and calculate "haddr" ourselves, it's cheap and reduces the number of function parameters. > { > - struct vm_area_struct *vma = vmf->vma; > - struct folio *folio = page_folio(page); > - pgtable_t pgtable; > - unsigned long haddr = vmf->address & HPAGE_PMD_MASK; > - vm_fault_t ret = 0; > + const int order = HPAGE_PMD_ORDER; > + struct folio *folio = vma_alloc_folio(gfp, order, vma, haddr, true); > > - VM_BUG_ON_FOLIO(!folio_test_large(folio), folio); > + if (unlikely(!folio)) { > + count_vm_event(THP_FAULT_FALLBACK); > + count_mthp_stat(order, MTHP_STAT_ANON_FAULT_FALLBACK); > + goto out; > + } > > + VM_BUG_ON_FOLIO(!folio_test_large(folio), folio); > if (mem_cgroup_charge(folio, vma->vm_mm, gfp)) { > folio_put(folio); > count_vm_event(THP_FAULT_FALLBACK); > count_vm_event(THP_FAULT_FALLBACK_CHARGE); > - count_mthp_stat(HPAGE_PMD_ORDER, MTHP_STAT_ANON_FAULT_FALLBACK); > - count_mthp_stat(HPAGE_PMD_ORDER, MTHP_STAT_ANON_FAULT_FALLBACK_CHARGE); > - return VM_FAULT_FALLBACK; > + count_mthp_stat(order, MTHP_STAT_ANON_FAULT_FALLBACK); > + count_mthp_stat(order, MTHP_STAT_ANON_FAULT_FALLBACK_CHARGE); > + goto out; > } > folio_throttle_swaprate(folio, gfp); > > - pgtable = pte_alloc_one(vma->vm_mm); > - if (unlikely(!pgtable)) { > - ret = VM_FAULT_OOM; > - goto release; > - } > - > - folio_zero_user(folio, vmf->address); > + folio_zero_user(folio, addr); > /* > * The memory barrier inside __folio_mark_uptodate makes sure that > * folio_zero_user writes become visible before the set_pmd_at() > * write. > */ > __folio_mark_uptodate(folio); > +out: > + return folio; > +} > + > +static void __pmd_thp_fault_success_stats(struct vm_area_struct *vma) > +{ > + count_vm_event(THP_FAULT_ALLOC); > + count_mthp_stat(HPAGE_PMD_ORDER, MTHP_STAT_ANON_FAULT_ALLOC); > + count_memcg_event_mm(vma->vm_mm, THP_FAULT_ALLOC); > +} Why isn't that moved into map_pmd_thp() Note that in this patch you do: map_pmd_thp(folio, vmf, vma, haddr); spin_unlock(vmf->ptl); __pmd_thp_fault_success_stats(vma); But in patch #2 map_pmd_thp(folio, vmf, vma, haddr); __pmd_thp_fault_success_stats(vma); goto unlock; release: folio_put(folio); unlock: spin_unlock(vmf->ptl); Please make that consistent, meaning: 1) Inline __pmd_thp_fault_success_stats() into map_pmd_thp(). No need to have the separated out. 2) Either do the PTL unlocking in __pmd_thp_fault_success_stats() or in the caller. In the caller is likely easiest. Adjusting the counters should be cheap, if not we could revisit this later with real data. > + > +static void map_pmd_thp(struct folio *folio, struct vm_fault *vmf, > + struct vm_area_struct *vma, unsigned long haddr) > +{ > + pmd_t entry; > + > + entry = mk_huge_pmd(&folio->page, vma->vm_page_prot); > + entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); > + folio_add_new_anon_rmap(folio, vma, haddr, RMAP_EXCLUSIVE); > + folio_add_lru_vma(folio, vma); > + set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); > + update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); It's quite weird to see a mixture of haddr and vmf->address, and likely this mixture is wrong or not not required. Looking at arc's update_mmu_cache_pmd() implementation, I cannot see how passing in the unaligned address would do the right thing. But maybe arc also doesn't trigger that code path ... who knows :) Staring at some other update_mmu_cache_pmd() users, it's quite inconsistent. Primarily only do_huge_pmd_numa_page() and __do_huge_pmd_anonymous_page() use the unaligned address. The others seem to use the aligned address ... as one would expect when modifying a PMD. I suggest to change this function to *not* pass in the vmf, and rename it to something like: static void folio_map_anon_pmd(struct folio *folio, struct vm_area_struct *vma, pmd_t *pmd, unsigned long haddr) Then use haddr also to do the update_mmu_cache_pmd(). > + add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); > + mm_inc_nr_ptes(vma->vm_mm); > +} > + > +static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf) > +{ > + struct vm_area_struct *vma = vmf->vma; > + struct folio *folio; > + pgtable_t pgtable; > + unsigned long haddr = vmf->address & HPAGE_PMD_MASK; > + vm_fault_t ret = 0; > + gfp_t gfp = vma_thp_gfp_mask(vma); Nit: While at it, try to use reverse christmas-tree where possible, makes things more reasible. You could make haddr const. struct vm_area_struct *vma = vmf->vma; unsigned long haddr = vmf->address & HPAGE_PMD_MASK; gfp_t gfp = vma_thp_gfp_mask(vma); struct folio *folio; vm_fault_t ret = 0; ... > + > + folio = pmd_thp_fault_alloc(gfp, vma, haddr, vmf->address); > + if (unlikely(!folio)) { > + ret = VM_FAULT_FALLBACK; > + goto release; > + } > + > + pgtable = pte_alloc_one(vma->vm_mm); > + if (unlikely(!pgtable)) { > + ret = VM_FAULT_OOM; > + goto release; > + } > > vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); > + Nit Unrelated change. > if (unlikely(!pmd_none(*vmf->pmd))) { > goto unlock_release; -- Cheers, David / dhildenb