From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 15 Feb 2005 07:21:06 -0800 From: Paul Jackson Subject: Re: [RFC 2.6.11-rc2-mm2 0/7] mm: manual page migration -- overview Message-Id: <20050215072106.508f65d2.pj@sgi.com> In-Reply-To: <4211BD88.70904@sgi.com> References: <20050212032535.18524.12046.26397@tomahawk.engr.sgi.com> <20050212155426.GA26714@logos.cnet> <20050212212914.GA51971@muc.de> <20050214163844.GB8576@lnx-holt.americas.sgi.com> <20050214191509.GA56685@muc.de> <42113921.7070807@sgi.com> <20050214191651.64fc3347.pj@sgi.com> <4211BD88.70904@sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Ray Bryant Cc: ak@muc.de, holt@sgi.com, marcelo.tosatti@cyclades.com, raybry@austin.rr.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: Ray wrote: > The exact ordering of when a task is moved to a new cpuset and when the > migration occurs doesn't matter, AFAIK, if we accept the notion that > a migrated task is in suspended state until after everything associated > with it (including the new cpuset definition) is done. The existance of _some_ sequence of system calls such that user space could, if it so chose, do the 'right' thing does not exonerate the kernel from enforcing its rules, on each call. The kernel certainly does not have a crystal ball that lets it say "ok - let this violation of my rules pass - I know that the caller will straighten things out before it lets anything ontoward occur (before it removes the suspension, in this case.) In other words, more directly, the kernel must return from each system call with everything in order, all its rules enforced. I still think that migration should honor cpusets, unless you can show me a good reason why that's too cumbersome. At least a migration patch for *-mm should honor cpusets. When the migration patch goes into Linus's main tree, then it should honor cpusets there too, if cpusets are already there. Or if migration goes into Linus's tree before cpusets, the onus would be on cpusets to add the changes to the migration code honoring cpusets, when and if cpusets followed along. -- I won't rest till it's the best ... Programmer, Linux Scalability Paul Jackson 1.650.933.1373, 1.925.600.0401 -- 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