From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <45BBCFE9.5010600@redhat.com> Date: Sat, 27 Jan 2007 17:19:21 -0500 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [RFC] Track mlock()ed pages References: <45B9A00C.4040701@yahoo.com.au> <20070126031300.59f75b06.akpm@osdl.org> <20070126101027.90bf3e63.akpm@osdl.org> <20070126104206.f0b45f74.akpm@osdl.org> In-Reply-To: <20070126104206.f0b45f74.akpm@osdl.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: Christoph Lameter , Nick Piggin , linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: Andrew Morton wrote: > Of course it would. But how do you know it is "too expensive"? We "scan > all the vmas mapping a page" as a matter of course in the page scanner - > millions of times a minute. If that's "too expensive" then ouch. We can do it lazily. At mlock time, move pages onto the mlocked list, unless they are there already. On munlock, move pages to the active list. For mlock-only memory (shared memory segments?) we could add a simple check to see if the next process on the list has the page mlocked, checking only that one. While scanning the active list, move mlocked pages that are found back onto the mlocked list. This lazy movement of pages will impact shared libraries, but probably not shared memory segments. Does this sound workable? -- Politics is the struggle between those who want to make their country the best in the world, and those who believe it already is. Each group calls the other unpatriotic. -- 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