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a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1701896857; x=1702501657; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=FWiJVJee8Ae6eLRLe/k0sR+dOBFv9TJldm8F95K/pME=; b=OvYWWJQe14sMIu0GJs0yFm77K9kfaLFTdYE3OaZjDZW3AebvMQ5jX7ZXq1muWhJE6/ Fv/IDRMgdbL1Xoa6pWdmfvR8sgckdPq+NADwt/LESHwfCoIjuylS9ltquG6HgyOVRYzj sUIcAFM4o0bPN+V3hK7o134EYaAHBDvTInZs9VXEzAp5ACbCPzZUZaiUUzJU5LrZncBu OeuKhKdzqAIxxvyl5UtzREOJ3OaU/tPa2K58HimdGgNfnAO8MsPrBZ9cPWiiWGb6Tp/t qjjZj/oqdLYzQM7qr9sbNMPTyH7J3r4TV/vnFwiowSkh+9ZzIv7FBXNwUr/qaWHES1od 0jOw== X-Gm-Message-State: AOJu0YxvvgjwhHhM5Y1EdTTCBtK7HCNBJceVwEKlxEgC4CWQYhtA+PkY U+nmVianpSxDK/JkPfC2F4z0sNYNrJr6GNa+3IdkIQ== X-Google-Smtp-Source: AGHT+IFQjAKqMvzci7bqRXKnmQiuPN2tBzZy5yeK5J2Q2g/TCKcGOpN0MrSz6JauubgQZ62nAWBZ0HCbCU0eSEHJpHE= X-Received: by 2002:a17:906:185:b0:a1d:d900:271b with SMTP id 5-20020a170906018500b00a1dd900271bmr1351024ejb.2.1701896857444; Wed, 06 Dec 2023 13:07:37 -0800 (PST) MIME-Version: 1.0 References: <20231206204442.771430-1-willy@infradead.org> In-Reply-To: <20231206204442.771430-1-willy@infradead.org> From: Yosry Ahmed Date: Wed, 6 Dec 2023 13:07:01 -0800 Message-ID: Subject: Re: [PATCH] mm: Support order-1 folios in the page cache To: "Matthew Wilcox (Oracle)" Cc: Andrew Morton , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Hugh Dickins , Viacheslav Dubeyko , "Kirill A. Shutemov" , Luis Chamberlain , Hannes Reinecke Content-Type: text/plain; charset="UTF-8" X-Rspam-User: X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 0575D100017 X-Stat-Signature: 53boytas98feryb66378t1ffqzrggkyn X-HE-Tag: 1701896858-920976 X-HE-Meta: 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 AsLJGDD4 BEfl+062XE20IabZcfnqf7pktgV8MvcOU65CiVo/SqLKYNjpOOM91NEWiI9k3Cu3y0Ezfz8rLDJhojtD5lsc9Z8VDF8nTA9eS6DdsWSiSc/XS8WSQDy0HUDaBhWyOGg355j+qgvdb9TAfkXc/INMegAD7fEHlvNdrOfu6cg2NkOMPMOGEzEcn/SofRcc7q6pzJv7jqWbeeAFiJIRuvhR8aNEjfZB1Di4fNJvX 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: [..] > @@ -2836,7 +2844,12 @@ void deferred_split_folio(struct folio *folio) > #endif > unsigned long flags; > > - VM_BUG_ON_FOLIO(folio_order(folio) < 2, folio); > + /* > + * Order 1 folios have no space for a deferred list, but we also > + * won't waste much memory by not adding them to the deferred list. > + */ > + if (folio_order(folio) <= 1) > + return; Would it be clearer if we have a folio_has_deferred_list() helper that has the check and the comment, instead of having this comment here and commentless checks elsewhere (or repeating the comment)?