From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: [Patch] shm cleanups References: Mime-Version: 1.0 (generated by tm-edit 7.108) Content-Type: text/plain; charset=US-ASCII From: Christoph Rohland Date: 04 Nov 1999 13:40:11 +0100 In-Reply-To: Ingo Molnar's message of "Thu, 4 Nov 1999 09:10:46 +0100 (CET)" Message-ID: Sender: owner-linux-mm@kvack.org Return-Path: To: Ingo Molnar Cc: MM mailing list , woodman@missioncriticallinux.com List-ID: Hi Ingo, Ingo Molnar writes: > On 3 Nov 1999, Christoph Rohland wrote: > > > I did test it a lot on SMP/HIGHMEM. Since 2.3.25 with and without this > > breaks on swapping shm and other high memory load conditions I could > > not verify everything. But I would like to see this in the mainstream > > kernel. I will then proceed debugging the swapping issues. > > (i can see the problems too, but i've got no explanation either, working > on it as well.) > > -- mingo After applying the following patch against ipc/shm.c (thanks to Larry Woodman for the first one): --- 2.3.25/ipc/shm.c Tue Nov 2 12:46:29 1999 +++ make25/ipc/shm.c Thu Nov 4 12:47:14 1999 @@ -788,10 +789,10 @@ unlock_kernel(); return 0; } - if (page_count(page_map)) + if (page_count(page_map) != 1) goto check_table; if (!(page_map = prepare_highmem_swapout(page_map))) - goto check_table; + goto failed; shp->shm_pages[idx] = swp_entry_to_pte(swap_entry); swap_successes++; shm_swp++; 791c791 < if (page_count(page_map)) --- > if (page_count(page_map) != 1) I get the same behaviour for shm swapping as on 2.3.22 as long as I only use 1G memory (HIGHMEM setting is always 64GB). I do get swapping also with 8GB of RAM, but it runs out of memory before running out of swap space since prepare_highmem_swapout is failing way to often. (It then locks up since it cannot free the shm segments and so is unable to free the memory. This should be perhaps addressed later in the oom handler. It cannot handle the case where nearly all memory is allocted in shm segments) Greetings Christoph -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://humbolt.geo.uu.nl/Linux-MM/