From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 21 Feb 2003 00:43:17 -0300 (BRT) From: Rik van Riel Subject: Re: [PATCH 2.5.62] Support for remap_page_range in objrmap In-Reply-To: <178650000.1045782627@flay> Message-ID: References: <121000000.1045777999@baldur.austin.ibm.com> <178650000.1045782627@flay> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: "Martin J. Bligh" Cc: Dave McCracken , Andrew Morton , Linux Memory Management List-ID: On Thu, 20 Feb 2003, Martin J. Bligh wrote: > > Here's the fix we discussed for remap_page_range. It sets the anon flag > > for pages in any vma used for nonlinear. It also requires that > > MAP_NONLINEAR be passed in at mmap time to flag the vma. > > Using the page based mechanism might also clear up some people's > concerns about small windows onto large shared areas for Oracle, > which will probably be using these nonlinear mappings anyway. Good point. Object based reverse mappings become unwieldy at about the same point where the objects themselves get unwieldy. A hybrid system with object based mappings in some cases and page based mappings in other cases might work very nicely... > Yes, I'm sure there are other corner cases that need to be addressed > as well ;-) There are, but at the moment I can't remember any as serious as the "1000 tasks with 1000 small mappings of the same shared memory segment" scenario. This hybrid system looks like it is worth exploring. regards, Rik -- Engineers don't grow up, they grow sideways. http://www.surriel.com/ http://kernelnewbies.org/ -- 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