From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 21 Jan 2005 12:28:54 -0200 From: Marcelo Tosatti Subject: Re: [PATCH] Avoiding fragmentation through different allocator Message-ID: <20050121142854.GH19973@logos.cnet> References: <20050120101300.26FA5E598@skynet.csn.ul.ie> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050120101300.26FA5E598@skynet.csn.ul.ie> Sender: owner-linux-mm@kvack.org Return-Path: To: Mel Gorman Cc: William Lee Irwin III , linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: On Thu, Jan 20, 2005 at 10:13:00AM +0000, Mel Gorman wrote: > Changelog since V5 > o Fixed up gcc-2.95 errors > o Fixed up whitespace damage > > Changelog since V4 > o No changes. Applies cleanly against 2.6.11-rc1 and 2.6.11-rc1-bk6. Applies > with offsets to 2.6.11-rc1-mm1 > > Changelog since V3 > o inlined get_pageblock_type() and set_pageblock_type() > o set_pageblock_type() now takes a zone parameter to avoid a call to page_zone() > o When taking from the global pool, do not scan all the low-order lists > > Changelog since V2 > o Do not to interfere with the "min" decay > o Update the __GFP_BITS_SHIFT properly. Old value broke fsync and probably > anything to do with asynchronous IO > > Changelog since V1 > o Update patch to 2.6.11-rc1 > o Cleaned up bug where memory was wasted on a large bitmap > o Remove code that needed the binary buddy bitmaps > o Update flags to avoid colliding with __GFP_ZERO changes > o Extended fallback_count bean counters to show the fallback count for each > allocation type > o In-code documentation Hi Mel, I was thinking that it would be nice to have a set of high-order intensive workloads, and I wonder what are the most common high-order allocation paths which fail. It mostly depends on hardware because most high-order allocations happen inside device drivers? What are the kernel codepaths which try to do high-order allocations and fallback if failed? To measure whether the cost of page migration offsets the ability to be able to deliver high-order allocations we want a set of meaningful performance tests? Its quite possible that not all unsatisfiable high-order allocations want to force page migration (which is quite expensive in terms of CPU/cache). Only migrate on __GFP_NOFAIL ? William, that same tradeoff exists for the zone balancing through migration idea you propose... -- 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: aart@kvack.org