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Mon, 13 May 2024 08:58:27 -0700 (PDT) Received: from [172.21.1.2] ([50.204.89.31]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-1ef0bf311d0sm80781775ad.132.2024.05.13.08.58.27 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 13 May 2024 08:58:27 -0700 (PDT) Message-ID: Date: Mon, 13 May 2024 17:58:21 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH linux-next] mm/huge_memory: remove redundant locking when parsing THP sysfs input To: xu.xin16@zte.com.cn, akpm@linux-foundation.org Cc: willy@infradead.org, shy828301@gmail.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20240511144048767fdB7EqYoMHEw6A5b6FrXM@zte.com.cn> 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: <20240511144048767fdB7EqYoMHEw6A5b6FrXM@zte.com.cn> 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-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: E1D3340028 X-Stat-Signature: x94wrab1z7qcumwmo45jrxqsceyfssnh X-HE-Tag: 1715616284-784391 X-HE-Meta: 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 1+/LWjOH 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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 11.05.24 08:40, xu.xin16@zte.com.cn wrote: > From: Ran Xiaokai > > Since sysfs_streq() only performs a simple memory comparison operation > and will not introduce any sleepable operation, So there is no > need to drop the lock when parsing input. Remove redundant lock > and unlock operations to make code cleaner. > > Signed-off-by: Ran Xiaokai > --- > mm/huge_memory.c | 10 ++-------- > 1 file changed, 2 insertions(+), 8 deletions(-) > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index 89f58c7603b2..87123a87cb21 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -478,32 +478,26 @@ static ssize_t thpsize_enabled_store(struct kobject *kobj, > int order = to_thpsize(kobj)->order; > ssize_t ret = count; > > + spin_lock(&huge_anon_orders_lock); > if (sysfs_streq(buf, "always")) { > - spin_lock(&huge_anon_orders_lock); > clear_bit(order, &huge_anon_orders_inherit); > clear_bit(order, &huge_anon_orders_madvise); > set_bit(order, &huge_anon_orders_always); > - spin_unlock(&huge_anon_orders_lock); > } else if (sysfs_streq(buf, "inherit")) { > - spin_lock(&huge_anon_orders_lock); > clear_bit(order, &huge_anon_orders_always); > clear_bit(order, &huge_anon_orders_madvise); > set_bit(order, &huge_anon_orders_inherit); > - spin_unlock(&huge_anon_orders_lock); > } else if (sysfs_streq(buf, "madvise")) { > - spin_lock(&huge_anon_orders_lock); > clear_bit(order, &huge_anon_orders_always); > clear_bit(order, &huge_anon_orders_inherit); > set_bit(order, &huge_anon_orders_madvise); > - spin_unlock(&huge_anon_orders_lock); > } else if (sysfs_streq(buf, "never")) { > - spin_lock(&huge_anon_orders_lock); > clear_bit(order, &huge_anon_orders_always); > clear_bit(order, &huge_anon_orders_inherit); > clear_bit(order, &huge_anon_orders_madvise); > - spin_unlock(&huge_anon_orders_lock); > } else > ret = -EINVAL; > + spin_unlock(&huge_anon_orders_lock); > > return ret; > } No strong opinion Reviewed-by: David Hildenbrand -- Cheers, David / dhildenb