From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: RE: [Lhms-devel] [PATCH 0/7] Fragmentation Avoidance V19 From: Rohit Seth In-Reply-To: <1131389934.25133.69.camel@localhost.localdomain> References: <20051107003452.3A0B41855A0@thermo.lanl.gov> <1131389934.25133.69.camel@localhost.localdomain> Content-Type: text/plain Date: Mon, 07 Nov 2005 12:51:01 -0800 Message-Id: <1131396662.18176.41.camel@akash.sc.intel.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Adam Litke Cc: Andy Nelson , ak@suse.de, nickpiggin@yahoo.com.au, akpm@osdl.org, arjan@infradead.org, arjanv@infradead.org, gmaxwell@gmail.com, haveblue@us.ibm.com, kravetz@us.ibm.com, lhms-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mbligh@mbligh.org, mel@csn.ul.ie, mingo@elte.hu, torvalds@osdl.org List-ID: On Mon, 2005-11-07 at 12:58 -0600, Adam Litke wrote: > I am currently working on an new approach to what you tried. It > requires fewer changes to the kernel and implements the special large > page usage entirely in an LD_PRELOAD library. And on newer kernels, > programs linked with the .x ldscript you mention above can run using all > small pages if not enough large pages are available. > Isn't it true that most of the times we'll need to be worrying about run-time allocation of memory (using malloc or such) as compared to static. > For the curious, here's how this all works: > 1) Link the unmodified application source with a custom linker script which > does the following: > - Align elf segments to large page boundaries > - Assert a non-standard Elf program header flag (PF_LINUX_HTLB) > to signal something (see below) to use large pages. We'll need a similar flag for even code pages to start using hugetlb pages. In this case to keep the kernel changes to minimum, RTLD will need to modified. > 2) Boot a kernel that supports copy-on-write for PRIVATE hugetlb pages > 3) Use an LD_PRELOAD library which reloads the PF_LINUX_HTLB segments into > large pages and transfers control back to the application. > COW, swap etc. are all very nice (little!) features that make hugetlb to get used more transparently. -rohit -- 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