From mboxrd@z Thu Jan 1 00:00:00 1970 Received: by wa-out-1112.google.com with SMTP id m33so3017978wag.8 for ; Mon, 24 Mar 2008 10:34:19 -0700 (PDT) Message-ID: <4cefeab80803241034m6f62c01fq669129db9959f47f@mail.gmail.com> Date: Mon, 24 Mar 2008 23:04:18 +0530 From: "Nitin Gupta" Subject: Re: [PATCH 3/6] compcache: TLSF Allocator interface In-Reply-To: <1206377777.6437.123.camel@lappy> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <200803242034.24264.nitingupta910@gmail.com> <1206377777.6437.123.camel@lappy> Sender: owner-linux-mm@kvack.org Return-Path: To: Peter Zijlstra Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: On Mon, Mar 24, 2008 at 10:26 PM, Peter Zijlstra wrote: > On Mon, 2008-03-24 at 20:34 +0530, Nitin Gupta wrote: > > Two Level Segregate Fit (TLSF) Allocator is used to allocate memory for > > variable size compressed pages. Its fast and gives low fragmentation. > > Following links give details on this allocator: > > - http://rtportal.upv.es/rtmalloc/files/tlsf_paper_spe_2007.pdf > > - http://code.google.com/p/compcache/wiki/TLSFAllocator > > > > This kernel port of TLSF (v2.3.2) introduces several changes but underlying > > algorithm remains the same. > > > > Changelog TLSF v2.3.2 vs this kernel port > > - Pool now dynamically expands/shrinks. > > It is collection of contiguous memory regions. > > - Changes to pool create interface as a result of above change. > > - Collect and export stats (/proc/tlsfinfo) > > - Cleanups: kernel coding style, added comments, macros -> static inline, etc. > > Can you explain why you need this allocator, why don't the current > kernel allocators work for you? > > kmalloc() allocates one of pre-defined sizes (as defined in kmalloc_sizes.h). This will surely cause severe fragmentation with these variable sized compressed pages. Whereas, TLSF maintains very fine grained size lists. In all the workloads I tested, it showed <5% fragmentation. Also, its very simple as just ~700 LOC. - Nitin -- 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