From 7c88a292dfcd6979e839493ef18d04770eb3bad0 Mon Sep 17 00:00:00 2001 From: Xishi Qiu Date: Thu, 28 Apr 2016 16:19:11 -0700 Subject: Documentation/sysctl/vm.txt: update numa_zonelist_order description Commit 3193913ce62c ("mm: page_alloc: default node-ordering on 64-bit NUMA, zone-ordering on 32-bit") changes the default value of numa_zonelist_order. Update the document. Signed-off-by: Xishi Qiu Cc: Mel Gorman Cc: Johannes Weiner Cc: Rik van Riel Cc: David Rientjes Cc: Kamezawa Hiroyuki Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/sysctl/vm.txt | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) (limited to 'Documentation/sysctl') diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt index cb0368459da3..34a5fece3121 100644 --- a/Documentation/sysctl/vm.txt +++ b/Documentation/sysctl/vm.txt @@ -581,15 +581,16 @@ Specify "[Nn]ode" for node order "Zone Order" orders the zonelists by zone type, then by node within each zone. Specify "[Zz]one" for zone order. -Specify "[Dd]efault" to request automatic configuration. Autoconfiguration -will select "node" order in following case. -(1) if the DMA zone does not exist or -(2) if the DMA zone comprises greater than 50% of the available memory or -(3) if any node's DMA zone comprises greater than 70% of its local memory and - the amount of local memory is big enough. - -Otherwise, "zone" order will be selected. Default order is recommended unless -this is causing problems for your system/application. +Specify "[Dd]efault" to request automatic configuration. + +On 32-bit, the Normal zone needs to be preserved for allocations accessible +by the kernel, so "zone" order will be selected. + +On 64-bit, devices that require DMA32/DMA are relatively rare, so "node" +order will be selected. + +Default order is recommended unless this is causing problems for your +system/application. ============================================================== -- cgit