From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: [PATCH] ummunotify: Userspace support for MMU notifications Date: Tue, 13 Apr 2010 20:02:54 +0200 Message-ID: <1271181774.4807.1868.camel@twins> References: <1271053337-7121-1-git-send-email-ebmunson@us.ibm.com> <20100412160359.1d9074dc.akpm@linux-foundation.org> <20100412235937.GF15629@obsidianresearch.com> <3251DDDA-D705-4B1E-9595-9C24709EF146@Sun.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Return-path: In-Reply-To: Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Roland Dreier Cc: =?ISO-8859-1?Q?H=E5kon?= Bugge , Jason Gunthorpe , Andrew Morton , Eric B Munson , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, rolandd-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org, pavel-+ZI9xUNit7I@public.gmane.org, mingo-X9Un+BFzKDI@public.gmane.org, jsquyres-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org List-Id: linux-rdma@vger.kernel.org On Tue, 2010-04-13 at 10:57 -0700, Roland Dreier wrote: > Are those system calls the only possible way that virtual to physical > mappings can change? Can't page migration or something like that > potentially affect things? And even if you did have hooks into every > system call that mattered (keep in mind that relying on glibc is not > enough, since an MPI application may not use glibc) would decoding them > and figuring out what happened really be preferable to a single event > type that tells you exactly what address range was affected? Yeah, virtual<->physical maps can change through swapping, page migration, memory compaction, huge-page aggregation (the latter two not yet being upstream). Even mlock() doesn't pin virtual<->physical maps. -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html