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authorMiao Xie <miaox@cn.fujitsu.com>2009-06-16 18:31:49 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2009-06-16 22:47:31 -0400
commit58568d2a8215cb6f55caf2332017d7bdff954e1c (patch)
treeffcdee457494ac78d6550b0aeac86536ca152e7b /init
parent950592f7b991f267d707d372b90f508bbe72acbc (diff)
cpuset,mm: update tasks' mems_allowed in time
Fix allocating page cache/slab object on the unallowed node when memory spread is set by updating tasks' mems_allowed after its cpuset's mems is changed. In order to update tasks' mems_allowed in time, we must modify the code of memory policy. Because the memory policy is applied in the process's context originally. After applying this patch, one task directly manipulates anothers mems_allowed, and we use alloc_lock in the task_struct to protect mems_allowed and memory policy of the task. But in the fast path, we didn't use lock to protect them, because adding a lock may lead to performance regression. But if we don't add a lock,the task might see no nodes when changing cpuset's mems_allowed to some non-overlapping set. In order to avoid it, we set all new allowed nodes, then clear newly disallowed ones. [lee.schermerhorn@hp.com: The rework of mpol_new() to extract the adjusting of the node mask to apply cpuset and mpol flags "context" breaks set_mempolicy() and mbind() with MPOL_PREFERRED and a NULL nodemask--i.e., explicit local allocation. Fix this by adding the check for MPOL_PREFERRED and empty node mask to mpol_new_mpolicy(). Remove the now unneeded 'nodes = NULL' from mpol_new(). Note that mpol_new_mempolicy() is always called with a non-NULL 'nodes' parameter now that it has been removed from mpol_new(). Therefore, we don't need to test nodes for NULL before testing it for 'empty'. However, just to be extra paranoid, add a VM_BUG_ON() to verify this assumption.] [lee.schermerhorn@hp.com: I don't think the function name 'mpol_new_mempolicy' is descriptive enough to differentiate it from mpol_new(). This function applies cpuset set context, usually constraining nodes to those allowed by the cpuset. However, when the 'RELATIVE_NODES flag is set, it also translates the nodes. So I settled on 'mpol_set_nodemask()', because the comment block for mpol_new() mentions that we need to call this function to "set nodes". Some additional minor line length, whitespace and typo cleanup.] Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Paul Menage <menage@google.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Yasunori Goto <y-goto@jp.fujitsu.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'init')
-rw-r--r--init/main.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/init/main.c b/init/main.c
index f6204f712e7c..5e0d3f047eaf 100644
--- a/init/main.c
+++ b/init/main.c
@@ -670,7 +670,6 @@ asmlinkage void __init start_kernel(void)
670 initrd_start = 0; 670 initrd_start = 0;
671 } 671 }
672#endif 672#endif
673 cpuset_init_early();
674 page_cgroup_init(); 673 page_cgroup_init();
675 enable_debug_pagealloc(); 674 enable_debug_pagealloc();
676 cpu_hotplug_init(); 675 cpu_hotplug_init();
@@ -867,6 +866,11 @@ static noinline int init_post(void)
867static int __init kernel_init(void * unused) 866static int __init kernel_init(void * unused)
868{ 867{
869 lock_kernel(); 868 lock_kernel();
869
870 /*
871 * init can allocate pages on any node
872 */
873 set_mems_allowed(node_possible_map);
870 /* 874 /*
871 * init can run on any cpu. 875 * init can run on any cpu.
872 */ 876 */