From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: [rfc][patch] mm: madvise(WILLNEED) for anonymous memory From: Peter Zijlstra In-Reply-To: <20071220171143.GV19691@waste.org> References: <1198155938.6821.3.camel@twins> <1198162078.6821.27.camel@twins> <1198169621.6821.44.camel@twins> <20071220171143.GV19691@waste.org> Content-Type: text/plain Date: Thu, 20 Dec 2007 18:15:59 +0100 Message-Id: <1198170959.30889.0.camel@lappy> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Matt Mackall Cc: Hugh Dickins , linux-kernel , linux-mm , Nick Piggin , riel , Lennart Poettering List-ID: On Thu, 2007-12-20 at 11:11 -0600, Matt Mackall wrote: > On Thu, Dec 20, 2007 at 05:53:41PM +0100, Peter Zijlstra wrote: > > > > On Thu, 2007-12-20 at 15:26 +0000, Hugh Dickins wrote: > > > > > The asynch code: perhaps not worth doing for MADV_WILLNEED alone, > > > but might prove useful for more general use when swapping in. > > > Not really the same as Con's swap prefetch, but worth looking > > > at that for reference. But I guess this becomes a much bigger > > > issue than you were intending to get into here. > > > > heh, yeah, got somewhat more complex that I'd hoped for. > > > > last patch for today (not even compile tested), will do a proper patch > > and test it tomorrow. > > > > --- > > A best effort MADV_WILLNEED implementation for anonymous memory. > > > > It adds a batch method to the page table walk routines so we can > > copy a few ptes while holding the kmap, which makes it possible to > > allocate the backing pages using GFP_KERNEL. > > Yuck. We actually need to just fix the atomic kmap issue in the > existing pagemap code rather than add a new method, I think. > > If performance of map/unmap is too slow at a granularity of 1, we can > add some internal batching in the CONFIG_HIGHPTE case. OK, sounds like a much better idea indeed. Will implement that. -- 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