From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nick Piggin Subject: Re: [rfc] more granular page table lock for hugepages Date: Sun, 14 Oct 2007 09:27:46 +1000 References: <20071008225234.GC27824@linux-os.sc.intel.com> <200710112139.51354.nickpiggin@yahoo.com.au> <20071012203421.GC19625@linux-os.sc.intel.com> In-Reply-To: <20071012203421.GC19625@linux-os.sc.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200710140927.46478.nickpiggin@yahoo.com.au> Sender: owner-linux-mm@kvack.org Return-Path: To: "Siddha, Suresh B" Cc: Ken Chen , Badari Pulavarty , linux-mm , tony.luck@intel.com List-ID: On Saturday 13 October 2007 06:34, Siddha, Suresh B wrote: > On Thu, Oct 11, 2007 at 04:39:51AM -0700, Nick Piggin wrote: > > Attached is the really basic sketch of how it will work. Any > > party poopers care tell me why I'm an idiot? :) > > I tried to be a party pooper but no. This sounds like a good idea as you > are banking on the 'mm' being the 'active mm'. Yeah, I think that's the common case, and definitely required for this lockless path to work. > sounds like two birds in one shot, I think. OK, I'll flesh it out a bit more and see if I can actually get something working (and working with hugepages too). > On ia64, we have "tpa" instruction which does the virtual to physical > address conversion for us. But talking to Tony, that will fault during not > present or vhpt misses. > > Well, for now, manual walk is probably the best we have. Hmm, we'd actually want it to fault, and go through the full handle_mm_fault path if possible, and somehow just give an -EFAULT if it can't be satisfied. The common case will be that a mapping does actually exist, but sometimes there won't be a pte entry... depending on the application, it may even be the common case to have a hot TLB entry too... I don't know, obviously the manual walk is needed to get a simple baseline. -- 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