Commit f3b39d47 authored Jun 16, 2009 by Miao Xie Committed by Linus Torvalds Jun 16, 2009

cpusets: restructure the function cpuset_update_task_memory_state()



The kernel still allocates the page caches on old node after modifying its
cpuset's mems when 'memory_spread_page' was set, or it didn't spread the
page cache evenly over all the nodes that faulting task is allowed to usr
after memory_spread_page was set.  it is caused by the old mem_allowed and
flags of the task, the current kernel doesn't updates them unless some
function invokes cpuset_update_task_memory_state(), it is too late
sometimes.We must update the mem_allowed and the flags of the tasks in
time.

Slab has the same problem.

The following patches fix this bug by updating tasks' mem_allowed and
spread flag after its cpuset's mems or spread flag is changed.

This patch:

Extract a function from cpuset_update_task_memory_state().  It will be
used later for update tasks' page/slab spread flags after its cpuset's
flag is set

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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent dcf975d5

kernel/cpuset.c

+19 −8

Original line number	Diff line number	Diff line
		@@ -331,6 +331,24 @@ static void guarantee_online_mems(const struct cpuset cs, nodemask_t pmask)
		BUG_ON(!nodes_intersects(*pmask, node_states[N_HIGH_MEMORY]));
		}

		/*
		* update task's spread flag if cpuset's page/slab spread flag is set
		*
		* Called with callback_mutex/cgroup_mutex held
		*/
		static void cpuset_update_task_spread_flag(struct cpuset *cs,
		struct task_struct *tsk)
		{
		if (is_spread_page(cs))
		tsk->flags \|= PF_SPREAD_PAGE;
		else
		tsk->flags &= ~PF_SPREAD_PAGE;
		if (is_spread_slab(cs))
		tsk->flags \|= PF_SPREAD_SLAB;
		else
		tsk->flags &= ~PF_SPREAD_SLAB;
		}

		/**
		* cpuset_update_task_memory_state - update task memory placement
		*
		@@ -388,14 +406,7 @@ void cpuset_update_task_memory_state(void)
		cs = task_cs(tsk); /* Maybe changed when task not locked */
		guarantee_online_mems(cs, &tsk->mems_allowed);
		tsk->cpuset_mems_generation = cs->mems_generation;
		if (is_spread_page(cs))
		tsk->flags \|= PF_SPREAD_PAGE;
		else
		tsk->flags &= ~PF_SPREAD_PAGE;
		if (is_spread_slab(cs))
		tsk->flags \|= PF_SPREAD_SLAB;
		else
		tsk->flags &= ~PF_SPREAD_SLAB;
		cpuset_update_task_spread_flag(cs, tsk);
		task_unlock(tsk);
		mutex_unlock(&callback_mutex);
		mpol_rebind_task(tsk, &tsk->mems_allowed);

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