From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sun, 4 Aug 2002 15:47:36 -0700 From: William Lee Irwin III Subject: Re: how not to write a search algorithm Message-ID: <20020804224736.GI4010@holomorphy.com> References: <3D4CE74A.A827C9BC@zip.com.au> <3D4D87CE.25198C28@zip.com.au> <20020804203804.GD4010@holomorphy.com> <3D4D9802.D1F208F0@zip.com.au> <20020804220218.GF4010@holomorphy.com> <3D4DAE2C.F45BC9D4@zip.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Description: brief message Content-Disposition: inline In-Reply-To: <3D4DAE2C.F45BC9D4@zip.com.au> Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: Rik van Riel , "linux-mm@kvack.org" List-ID: On Sun, Aug 04, 2002 at 03:43:56PM -0700, Andrew Morton wrote: > Getting the kernel back to the level of performance and stability > which it had before the rmap patch has to be the first step. > 1) 50% increase in system load on fork/exec/exit workloads > 2) Will oops on pte_chain oom > 3) pte_highmem is bust > 4) tripled ZONE_NORMAL consumption > 5) pte chains go wrong with ntpd > The first three or four here are fatal to the retention of the > reverse map, IMO. Futzing around fixing them is taking time > and is holding up other work. > I may have a handle on 1). Still working it. (2) only needs the reservation bits from the preceding post if it's just dealing with kmem_cache_alloc() returning NULL. (3) I ground out the half-assed quick & dirty "fish the pfn out of the kmap pte" a.k.a. virt_to_fix() and use physaddrs in pte_chains thingie and handed it off to others to debug/clean up/push. (4) is part of the known tradeoff AFAIK, but phillips may have something taking it down to only double or so Cheers, Bill -- 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/