From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <428B55E3.1000201@engr.sgi.com> Date: Wed, 18 May 2005 09:49:07 -0500 From: Ray Bryant MIME-Version: 1.0 Subject: Re: [Lhms-devel] Re: [PATCH 2.6.12-rc3 1/8] mm: manual page migration-rc2 -- xfs-extended-attributes-rc2.patch References: <20050511043756.10876.72079.60115@jackhammer.engr.sgi.com> <20050511043802.10876.60521.51027@jackhammer.engr.sgi.com> <20050511071538.GA23090@infradead.org> <4281F650.2020807@engr.sgi.com> <20050511125932.GW25612@wotan.suse.de> <42825236.1030503@engr.sgi.com> <20050511193207.GE11200@wotan.suse.de> <20050512104543.GA14799@infradead.org> <4289719A.20807@engr.sgi.com> <20050517232007.018d52ab.pj@sgi.com> In-Reply-To: <20050517232007.018d52ab.pj@sgi.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Paul Jackson Cc: hch@infradead.org, ak@suse.de, raybry@sgi.com, taka@valinux.co.jp, marcelo.tosatti@cyclades.com, haveblue@us.ibm.com, linux-mm@kvack.org, nathans@sgi.com, raybry@austin.rr.com, lhms-devel@lists.sourceforge.net, jes@wildopensource.com List-ID: Paul Jackson wrote: > Ray wrote: > >>If one were to use madvise() or mbind() to apply the migration >>policy flags ... then ... it's necessary to reach down to a common subobject, >>(such as the file struct, address space struct, or inode) and mark >>that. > > > As I wrote Ray offline earlier today (before noticing this thread), I > suggested considering adding another flag to fcntl(), not madvise/mbind, > since fcntl() is sometimes used to make changes to the underlying > in-core inode. > > My rough idea was to have a S_SKIPMIGRATE flag in the in-core > inode->i_flag's, defaulting to off, which could be set and gotten via > fcntl on any file descriptor open on that inode. The value set would > persist so long as some file held that dentry->inode open, or until > changed again. Just before invoking the call to migrate a task, user > code could examine each named file mapped into the task, and by opening > each said file and performing the appropriate fcntl(), mark whether or > not pages from that mapped file should be migrated. > Actually, we need two flags: S_SKIPMIGRATE, and S_MIGRATE_NON_SHARED. I personally prefer using mbind() to set these attributes in the address space object that maps a particular virtual address range, I guess I don't see the advantage of invoking file system operations to describe how memory should be dealt with in a migration operation. So I'd prefer to keep all of the operations in the memory space, hence mbind(). This makes sense to me since the migration operation is a policy issue, and mbind() is in the business of setting memory policy. -- Best Regards, Ray ----------------------------------------------- Ray Bryant 512-453-9679 (work) 512-507-7807 (cell) raybry@sgi.com raybry@austin.rr.com The box said: "Requires Windows 98 or better", so I installed Linux. ----------------------------------------------- -- 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