From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from max.phys.uu.nl (max.phys.uu.nl [131.211.32.73]) by kvack.org (8.8.7/8.8.7) with ESMTP id TAA03916 for ; Thu, 26 Nov 1998 19:00:49 -0500 Received: from mirkwood.dummy.home (root@anx1p7.phys.uu.nl [131.211.33.96]) by max.phys.uu.nl (8.8.7/8.8.7/hjm) with ESMTP id BAA22165 for ; Fri, 27 Nov 1998 01:00:45 +0100 (MET) Received: from localhost (riel@localhost) by mirkwood.dummy.home (8.9.0/8.8.3) with SMTP id AAA00557 for ; Fri, 27 Nov 1998 00:23:35 +0100 Date: Fri, 27 Nov 1998 00:23:33 +0100 (CET) From: Rik van Riel Reply-To: Rik van Riel Subject: [PATCH] swapin readahead Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org To: Linux MM List-ID: Hi, here is a very first primitive version of as swapin readahead patch. It seems to give much increased throughput to swap and the desktop switch time has decreased noticably. The checks are all needed. The first two checks are there to avoid annoying messages from swap_state.c :)) The third check is to make sure we always keep at least as much swapout bandwidth as swapin bandwidth. We need that to keep the system alive under heavy circumstances. I am now testing the patch quite heavily (200+ swap IOs/second) without any errors showing up in my xconsole, so I guess that means you can have fun too :) cheers, Rik -- now completely used to dvorak kbd layout... +-------------------------------------------------------------------+ | Linux memory management tour guide. H.H.vanRiel@phys.uu.nl | | Scouting Vries cubscout leader. http://www.phys.uu.nl/~riel/ | +-------------------------------------------------------------------+ --- mm/page_alloc.c.orig Thu Nov 26 11:26:49 1998 +++ mm/page_alloc.c Thu Nov 26 23:48:42 1998 @@ -370,9 +370,28 @@ pte_t * page_table, unsigned long entry, int write_access) { unsigned long page; + int i; struct page *page_map; + unsigned long offset = SWP_OFFSET(entry); + struct swap_info_struct *swapdev = SWP_TYPE(entry) + swap_info; page_map = read_swap_cache(entry); + + /* + * Primitive swap readahead code. We simply read the + * next 16 entries in the swap area. The break below + * is needed or else the request queue will explode :) + */ + for (i = 1; i++ < 16;) { + offset++; + if (!swapdev->swap_map[offset] || offset >= swapdev->max + || atomic_read(&nr_async_pages) > + pager_daemon.swap_cluster / 2) + break; + read_swap_cache_async(SWP_ENTRY(SWP_TYPE(entry), offset), +0); + break; + } if (pte_val(*page_table) != entry) { if (page_map) --- mm/page_io.c.orig Thu Nov 26 11:26:49 1998 +++ mm/page_io.c Thu Nov 26 11:30:43 1998 @@ -60,7 +60,7 @@ } /* Don't allow too many pending pages in flight.. */ - if (atomic_read(&nr_async_pages) > SWAP_CLUSTER_MAX) + if (atomic_read(&nr_async_pages) > pager_daemon.swap_cluster) wait = 1; p = &swap_info[type]; -- This is a majordomo managed list. To unsubscribe, send a message with the body 'unsubscribe linux-mm me@address' to: majordomo@kvack.org