From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: blk_congestion_wait racy? Message-ID: From: Martin Schwidefsky Date: Thu, 11 Mar 2004 19:24:48 +0100 MIME-Version: 1.0 Content-type: text/plain; charset=ISO-8859-1 Content-transfer-encoding: 8BIT Sender: owner-linux-mm@kvack.org Return-Path: To: Nick Piggin Cc: Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: > Martin, have you tried adding this printk? Sorry for the delay. I had to get 2.6.4-mm1 working before doing the "ouch" test. The new pte_to_pgprot/pgoff_prot_to_pte stuff wasn't easy. I tested 2.6.4-mm1 with the blk_run_queues move and the ouch printk. The first interesting observation is that 2.6.4-mm1 behaves MUCH better then 2.6.4: 2.6.4-mm1 with 1 cpu # time ./mempig 600 Count (1Meg blocks) = 600 600 of 600 Done. real 0m2.587s user 0m0.100s sys 0m0.730s # 2.6.4-mm1 with 2 cpus # time ./mempig 600 Count (1Meg blocks) = 600 600 of 600 Done. real 0m10.313s user 0m0.160s sys 0m0.780s # 2.6.4 takes > 1min for the test with 2 cpus. The second observation is that I get only a few "ouch" messages. They all come from the blk_congestion_wait in try_to_free_pages, as expected. What I did not expect is that I only got 9 "ouches" for the run with 2 cpus. blue skies, Martin Linux/390 Design & Development, IBM Deutschland Entwicklung GmbH Schonaicherstr. 220, D-71032 Boblingen, Telefon: 49 - (0)7031 - 16-2247 E-Mail: schwidefsky@de.ibm.com -- 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