From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: Query re: mempolicy for page cache pages From: Lee Schermerhorn In-Reply-To: <20060518111416.51de0127.akpm@osdl.org> References: <1147974599.5195.96.camel@localhost.localdomain> <20060518111416.51de0127.akpm@osdl.org> Content-Type: text/plain Date: Thu, 18 May 2006 15:10:18 -0400 Message-Id: <1147979418.5195.157.camel@localhost.localdomain> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: linux-mm@kvack.org, clameter@sgi.com, ak@suse.de, stevel@mvista.com List-ID: On Thu, 2006-05-18 at 11:14 -0700, Andrew Morton wrote: > Lee Schermerhorn wrote: > > > > 1) What ever happened to Steve's patch set? > > They were based on Andi's 4-level-pagetable work. Then we merged Nick's > 4-level-pagetable work instead, so > numa-policies-for-file-mappings-mpol_mf_move.patch broke horridly and I > dropped it. Steve said he'd redo the patch based on the new pagetable code > and would work with SGI on getting it benchmarked, but that obviously > didn't happen. Thanks for the info Andrew. > > I was a bit concerned about the expansion in sizeof(address_space), but we > ended up agreeing that it's numa-only and NUMA machines tend to have lots > of memory anyway. That being said, it would still be better to have a > pointer to a refcounted shared_policy in the address_space if poss, rather > than aggregating the whole thing. Yes, I was concerned about that, too. I do use a pointer to the shared policy struct in the address space, allocating it only if one actually applies a policy. A null pointer results in current behavior: fall back to process then global default policy. Even so, the pointer member would only be included under CONFIG_NUMA. As far as reference counting: I didn't think it would be necessary, because it appears to me that the address space structs are one to one with the inodes and persists as long as the inode does. Is this correct? If so, then the shared policy struct would only be deleted when the inode goes away. I may have a race, but I didn't think one could be doing an insert or lookup w/o holding locks/references on structs that would prevent the inode from being destroyed. But, may turn out to be moot, heh? Lee -- 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