From mboxrd@z Thu Jan 1 00:00:00 1970 From: Con Kolivas Subject: Re: [PATCH] mm: swap prefetch improvements Date: Sat, 12 May 2007 17:28:34 +1000 References: <20070430162007.ad46e153.akpm@linux-foundation.org> <200705121516.00070.kernel@kolivas.org> <20070511225111.fee05bb9.pj@sgi.com> In-Reply-To: <20070511225111.fee05bb9.pj@sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200705121728.34987.kernel@kolivas.org> Sender: owner-linux-mm@kvack.org Return-Path: To: Paul Jackson Cc: nickpiggin@yahoo.com.au, ray-lk@madrabbit.org, mingo@elte.hu, ck@vds.kolivas.org, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: On Saturday 12 May 2007 15:51, Paul Jackson wrote: > Con wrote: > > Hmm I'm not really sure what it takes to make it cpuset aware; > > ... > > It is numa aware to some degree. It stores the node id and when it starts > > prefetching it only prefetches to nodes that are suitable for prefetching > > to ... > > It would be absolutely trivial to add a check for 'number_of_cpusets' <= > > 1 in the prefetch_enabled() function. Would you like that? > > Hmmm ... it seems that we shadow boxing here ... trying to pick a solution > to solve a problem when we aren't even sure we have a problem, much less > what the problem is. > > That does not usually lead to the right path. > > Could you put some more effort into characterizing what problems > can arise if one has prefetch and cpusets active at the same time? > > My first wild guess is that the only incompatibility would have been that > prefetch might mess up NUMA placement (get pages on wrong nodes), which > it seems you have tried to address in your current patches. So it would > not surprise me if there was no problem here. Ummm this is what I've been saying for over a year now but noone has been listening. > We may just have to lean on Nick some more, if he is the only one who > understands what the problem is, to try again to explain it to us. -- -ck -- 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