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[2003:cb:c745:2300:653:c844:4858:570f]) by smtp.gmail.com with ESMTPSA id f6-20020a05600c154600b00418a02674edsm3469787wmg.38.2024.04.17.10.05.49 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 17 Apr 2024 10:05:50 -0700 (PDT) Message-ID: Date: Wed, 17 Apr 2024 19:05:49 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v8 3/3] mm/madvise: optimize lazyfreeing with mTHP in madvise_free To: Lance Yang , akpm@linux-foundation.org Cc: ryan.roberts@arm.com, 21cnbao@gmail.com, mhocko@suse.com, fengwei.yin@intel.com, zokeefe@google.com, shy828301@gmail.com, xiehuan09@gmail.com, wangkefeng.wang@huawei.com, songmuchun@bytedance.com, peterx@redhat.com, minchan@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20240417141436.77963-1-ioworker0@gmail.com> <20240417141436.77963-4-ioworker0@gmail.com> From: David Hildenbrand 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: <20240417141436.77963-4-ioworker0@gmail.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 59D14A0010 X-Stat-Signature: 74g8xxuhukre6hniozsnyok3gzpp7nh4 X-Rspam-User: X-HE-Tag: 1713373555-500017 X-HE-Meta: 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 ekVnBF83 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 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 17.04.24 16:14, Lance Yang wrote: > This patch optimizes lazyfreeing with PTE-mapped mTHP[1] > (Inspired by David Hildenbrand[2]). We aim to avoid unnecessary folio > splitting if the large folio is fully mapped within the target range. > > If a large folio is locked or shared, or if we fail to split it, we just > leave it in place and advance to the next PTE in the range. But note that > the behavior is changed; previously, any failure of this sort would cause > the entire operation to give up. As large folios become more common, > sticking to the old way could result in wasted opportunities. > > On an Intel I5 CPU, lazyfreeing a 1GiB VMA backed by PTE-mapped folios of > the same size results in the following runtimes for madvise(MADV_FREE) in > seconds (shorter is better): > > Folio Size | Old | New | Change > ------------------------------------------ > 4KiB | 0.590251 | 0.590259 | 0% > 16KiB | 2.990447 | 0.185655 | -94% > 32KiB | 2.547831 | 0.104870 | -95% > 64KiB | 2.457796 | 0.052812 | -97% > 128KiB | 2.281034 | 0.032777 | -99% > 256KiB | 2.230387 | 0.017496 | -99% > 512KiB | 2.189106 | 0.010781 | -99% > 1024KiB | 2.183949 | 0.007753 | -99% > 2048KiB | 0.002799 | 0.002804 | 0% > > [1] https://lkml.kernel.org/r/20231207161211.2374093-5-ryan.roberts@arm.com > [2] https://lore.kernel.org/linux-mm/20240214204435.167852-1-david@redhat.com > > Signed-off-by: Lance Yang Some of the changes could have been moved into separate patches to ease review ;) At least the folio_pte_batch() change and factoring out some stuff from madvise_cold_or_pageout_pte_range(). But see below on the latter. > --- > mm/internal.h | 12 ++++- > mm/madvise.c | 141 ++++++++++++++++++++++++++++---------------------- > mm/memory.c | 4 +- > 3 files changed, 91 insertions(+), 66 deletions(-) [...] > diff --git a/mm/madvise.c b/mm/madvise.c > index f5e3699e7b54..d6f1889d6308 100644 > --- a/mm/madvise.c > +++ b/mm/madvise.c > @@ -321,6 +321,39 @@ static inline bool can_do_file_pageout(struct vm_area_struct *vma) > file_permission(vma->vm_file, MAY_WRITE) == 0; > } > > +static inline int madvise_folio_pte_batch(unsigned long addr, unsigned long end, > + struct folio *folio, pte_t *ptep, > + pte_t pte, bool *any_young, > + bool *any_dirty) > +{ > + int max_nr = (end - addr) / PAGE_SIZE; > + const fpb_t fpb_flags = FPB_IGNORE_DIRTY | FPB_IGNORE_SOFT_DIRTY; Reverse Christmas tree looks nicer ;) > + > + return folio_pte_batch(folio, addr, ptep, pte, max_nr, fpb_flags, NULL, > + any_young, any_dirty); > +} > + > +static inline bool madvise_pte_split_folio(struct mm_struct *mm, pmd_t *pmd, > + unsigned long addr, > + struct folio *folio, pte_t **pte, > + spinlock_t **ptl) > +{ > + int err; > + > + if (!folio_trylock(folio)) > + return false; > + > + folio_get(folio); > + pte_unmap_unlock(*pte, *ptl); > + err = split_folio(folio); > + folio_unlock(folio); > + folio_put(folio); > + > + *pte = pte_offset_map_lock(mm, pmd, addr, ptl); Staring at this helper again, I am really not sure if we should have it. Calling semantics are "special" and that pte_t **pte is just ... "special" as well ;) Can we just leave that part as is, in the caller? That would also mean less madvise_cold_or_pageout_pte_range() churn ... which i would welcome as part of this patch. [...] > @@ -741,19 +767,10 @@ static int madvise_free_pte_range(pmd_t *pmd, unsigned long addr, > } > > if (pte_young(ptent) || pte_dirty(ptent)) { > - /* > - * Some of architecture(ex, PPC) don't update TLB > - * with set_pte_at and tlb_remove_tlb_entry so for > - * the portability, remap the pte with old|clean > - * after pte clearing. > - */ > - ptent = ptep_get_and_clear_full(mm, addr, pte, > - tlb->fullmm); > - > - ptent = pte_mkold(ptent); > - ptent = pte_mkclean(ptent); > - set_pte_at(mm, addr, pte, ptent); > - tlb_remove_tlb_entry(tlb, pte, addr); > + clear_young_dirty_ptes(vma, addr, pte, nr, > + CYDP_CLEAR_YOUNG | > + CYDP_CLEAR_DIRTY); That indent looks odd. I suggest simply having a local variable const cydp_t cydp_flags = CYDP_CLEAR_YOUNG | CYDP_CLEAR_DIRTY; and then use cydp_flags here that will make this easier to read. -- Cheers, David / dhildenb