From mboxrd@z Thu Jan 1 00:00:00 1970 From: Simon Jeons Subject: Re: PAGE_CACHE_SIZE vs. PAGE_SIZE Date: Tue, 19 Feb 2013 18:32:36 +0800 Message-ID: <512354C4.2040705@gmail.com> References: <20130118155724.GA8507@otc-wbsnb-06> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Andrew Morton , Linus Torvalds , Al Viro , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Wu Fengguang , Jan Kara , Nick Piggin , Andrea Arcangeli , Andi Kleen , "Kirill A. Shutemov" To: "Kirill A. Shutemov" Return-path: In-Reply-To: <20130118155724.GA8507@otc-wbsnb-06> Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.vger.kernel.org On 01/18/2013 11:57 PM, Kirill A. Shutemov wrote: > Hi, > > PAGE_CACHE_* macros were introduced long time ago in hope to implement > page cache with larger chunks than one page in future. > > In fact it was never done. > > Some code paths assume PAGE_CACHE_SIZE <= PAGE_SIZE. E.g. we use > zero_user_segments() to clear stale parts of page on cache filling, but > the function is implemented only for individual small page. > > It's unlikely that global switch to PAGE_CACHE_SIZE > PAGE_SIZE will never > happen since it will affect to much code at once. > > I think support of larger chunks in page cache can be in implemented in > some form of THP with per-fs enabling. IIRC, you try to implement THP support page cache, then PAGE_CACHE_SIZE maybe don't need any more. > > Is it time to get rid of PAGE_CACHE_* macros? > I can prepare patchset if it's okay. > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org