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[2003:cb:c709:1700:969:8e2b:e8bb:46be]) by smtp.gmail.com with ESMTPSA id l19-20020a05600c2cd300b003dfefe115b9sm19847507wmc.0.2023.02.14.09.52.49 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 14 Feb 2023 09:52:50 -0800 (PST) Message-ID: <5064ee08-792f-14f2-6f2d-26e81af8a239@redhat.com> Date: Tue, 14 Feb 2023 18:52:49 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.6.0 Subject: Re: [PATCH v2 0/4] Change the return value for page isolation functions To: Baolin Wang , akpm@linux-foundation.org Cc: torvalds@linux-foundation.org, sj@kernel.org, hannes@cmpxchg.org, mhocko@kernel.org, roman.gushchin@linux.dev, shakeelb@google.com, muchun.song@linux.dev, naoya.horiguchi@nec.com, linmiaohe@huawei.com, osalvador@suse.de, mike.kravetz@oracle.com, willy@infradead.org, damon@lists.linux.dev, cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: From: David Hildenbrand Organization: Red Hat In-Reply-To: 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: rspam03 X-Stat-Signature: dzd5dje334gm8siixywi6ish54geagnz X-Rspamd-Queue-Id: BA2B980004 X-HE-Tag: 1676397174-902989 X-HE-Meta: U2FsdGVkX19XRcDIOvlt+dg4qEVj4AnfD6w4jxLIllZdYa8L2rd8auVPrL0RtVnV/8X8dCt2cnV4ZlvTL1aXMr1kXm7HwcEu+QGd4y7GnVdimVVq+FQiYeoqTI1deWy6EzHyGYdjMnX4KdZb8V1GKSolncq5Vyj8f5D/B0YIvJeRhbGhA7lSxnNdeepaBRwK6jLLqMOVT+/WowIRcP+IbZ/7sv4YWtAMPsYb0+fT21UrL1wKtyAY1KgvD8wod+Zj0XpijbBWJMhv+oM2oaZsM//FHkqK+Gth4UkiYbkx2/1fZUcTiYS/8IKNA7IEw7ZzTe4+mHJHxEVaZMCpDsM8RzjjkucZKiSjUzYW/3+ZQXKlKveq4SCUxbESw486g0ypxpRcCYwRtv5y1ipJQ0oHuflDxvn6KkQLoFMSQMYbiDczmNmh4rIAPj1CsaVv64eGY4wb2QkECQkpoomhW/2uHhd3IFelBejQEyA7wo63y7hY/mV9QsOCfFTNE24DtP0IHf8h7dNztP9lpNbpt89+pCHW/SKy+eu9TFRtJPxoIDiFOss/W8/eRvhbV4HaGbbQD/tje5Twn8Zy3r1lbVzD7w2johlRcIZ8VijrunlOoY+7s9HGdW76Mav6iSB1AuF1rNdldrNiQlKOTqU7SkfTu8rPazC5OJTGt6uRzV9YXt41fw35Tmq3gx+w+pMxx+BkmIqSNL5vnt1aJkTFKTT/CzdZCWiU6kp1pF210m3gOH7mMpsXnhpPUit5BOyIvV6OPcFJlPOlZDjsXbHneezIcHEyP1wWY+wPVbqgkuLwykSzJp8jwB+XVym6VS2ouXSS8hLzq7SGb2T/v/Es4kaf0I/dqJ70W+toZAUlZo/YUKa667ewMQc++W2f67pcP/kCuvuKQlSD3F5Jx/ZCw4kM1wFyYpZ/0RDwfRCOET85wnVto+5UvcMkvNrZobCP/UR9Q/cjAVorw9tyyVvls44 QxTG/MW9 b4wlLTuz2XL/fGhtyOTfe8JMKGjNm/Z3p1++eqawuP+QlPx/8uZL+OpBrEord5GGvv/KWYmfXsORMwPH99/j0CxgTo0W4y2+bAq+JS9UV28HFNctW4TJNf3VTWJFayejLFbSvPMWlpUC9ItY0NgtZHDxv4J6KfFYiOua2ykJnCrf26yb+JgFXVq9xguScsvKU+uHPUeYNeCaD9NSpB+IZDBh4YdQ8OaHIoayV9ZGuJjLjAK+sArKY4DZ9aTR/ygFaqx8ru3dnzgtcg37riFDPjviQkXudlqZV6fv3TZUdLJy5RCPypexZ0bZYQJC9HgR4wvX2i+SKjnOGXvI= 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: On 14.02.23 14:59, Baolin Wang wrote: > Now the page isolation functions did not return a boolean to indicate > success or not, instead it will return a negative error when failed > to isolate a page. So below code used in most places seem a boolean > success/failure thing, which can confuse people whether the isolation > is successful. > > if (folio_isolate_lru(folio)) > continue; > > Moreover the page isolation functions only return 0 or -EBUSY, and > most users did not care about the negative error except for few users, > thus we can convert all page isolation functions to return a boolean > value, which can remove the confusion to make code more clear. > > No functional changes intended in this patch series. > > Changes from v1: > - Convert all isolation functions to return bool. Acked-by: David Hildenbrand Although it's controversial if if (!ret) ret = -EBUSY; else ret = 0; is really appealing to the readers eye :) ret = ret ? 0 : -EBUSY; It's still confusing. would be better as ret = isolated ? 0 : -EBUSY; IOW, not reusing the "int ret" variable. -- Thanks, David / dhildenb