From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: text/plain; charset="iso-8859-1" From: Ed Tomlinson Subject: Re: severely bloated slabs Date: Tue, 30 Jul 2002 20:13:01 -0400 References: <20020730172341.GD29537@holomorphy.com> <649629297.1028025550@[10.10.2.3]> <20020730175339.GF29537@holomorphy.com> In-Reply-To: <20020730175339.GF29537@holomorphy.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Message-Id: <200207302013.01958.tomlins@cam.org> Sender: owner-linux-mm@kvack.org Return-Path: To: William Lee Irwin III , "Martin J. Bligh" Cc: linux-mm@kvack.org List-ID: On July 30, 2002 01:53 pm, William Lee Irwin III wrote: > At some point in the past, I wrote: > >> 132MB of ZONE_NORMAL on a 16GB i386 box tied up in buffer_head slabs > >> when all of 3% of it is in use gives me the willies. Periodic slab > >> pruning anyone? Might be useful in addition to slab-in-lru. > > On Tue, Jul 30, 2002 at 10:39:35AM -0700, Martin J. Bligh wrote: > > As long as we give this up under memory pressure, why does this > > matter? > > Mostly a question of response time and long idle times being a good > indicator of upcoming workload shifts. I'd say it's behaving as > designed, but not as desired. Was this with full rmap + slablru or with a linus kernel? With slablru I would expect this to happen to some extent. When vm pressure picks up slablru is fast to free the 'old' slabs... On the other hand, if periodic prunes are really a good idea, it would be easy to have slablru do them for us. As it stands now, slablru adds a flag bit to each slab cache telling slablru to prune the cache instead of just the page encounted. This flag gets set when we are able to add a page to the lru (when the pagemap_lru lock is busy). I would not be hard to set this flag under other conditions. Ed -- 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/