From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 8 Apr 2008 19:47:40 -0700 From: Andrew Morton Subject: Re: [RFC][PATCH 0/6] compcache: Compressed Caching Message-Id: <20080408194740.1219e8b8.akpm@linux-foundation.org> In-Reply-To: <200803210129.59299.nitingupta910@gmail.com> References: <200803210129.59299.nitingupta910@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: nitingupta910@gmail.com Cc: linux-mm@kvack.org List-ID: On Fri, 21 Mar 2008 01:29:58 +0530 Nitin Gupta wrote: > Subject: [RFC][PATCH 0/6] compcache: Compressed Caching Didn't get many C's, did it? Be sure to cc linux-kernel on the next version. > Hi All, > > This implements a RAM based block device which acts as swap disk. > Pages swapped to this disk are compressed and stored in memory itself. > This allows more applications to fit in given amount of memory. This is > especially useful for embedded devices, OLPC and small desktops > (aka virtual machines). > > Project home: http://code.google.com/p/compcache/ > > It consists of following components: > - compcache.ko: Creates RAM based block device > - tlsf.ko: Two Level Segregate Fit (TLSF) allocator > - LZO de/compressor: (Already in mainline) > > Project home contains some performance numbers for TLSF and LZO. > For general desktop use, this is giving *significant* performance gain > under memory pressure. For now, it has been tested only on x86. The values of "*significant*" should be exhaustively documented in the patch changelogs. That is 100%-the-entire-whole-point of the patchset! Omitting that information tends to reduce the number of C's. Please feed all diffs through scripts/checkpatch.pl, contemplate the result. kmap_atomic() is (much) preferred over kmap(). flush_dcache_page() is needed after the CPU modifies pagecache or anon page by hand (generally linked to kmap[_atomic]()). The changelogs should include *complete* justification for the introduction of a new allocator. What problem is it solving, what are the possible solutions to that problem, why this one was chosen, etc. It's a fairly big deal. -- 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