Messages in this thread Patch in this message | | | Date | Tue, 27 Nov 2007 16:09:41 -0800 (PST) | From | Christoph Lameter <> | Subject | Re: [PATCH 1/1] mm: Prevent dereferencing non-allocated per_cpu variables |
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On Tue, 27 Nov 2007, Andrew Morton wrote:
> I don't recall anyone ever demonstrating that prefetch is useful in-kernel.
vmstat: remove prefetch
Remove the prefetch logic in order to avoid touching impossible per cpu areas.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
--- mm/vmstat.c | 11 ++--------- 1 file changed, 2 insertions(+), 9 deletions(-)
Index: linux-2.6/mm/vmstat.c =================================================================== --- linux-2.6.orig/mm/vmstat.c 2007-11-27 16:04:15.345713812 -0800 +++ linux-2.6/mm/vmstat.c 2007-11-27 16:07:00.552713192 -0800 @@ -21,21 +21,14 @@ EXPORT_PER_CPU_SYMBOL(vm_event_states); static void sum_vm_events(unsigned long *ret, cpumask_t *cpumask) { - int cpu = 0; + int cpu; int i; memset(ret, 0, NR_VM_EVENT_ITEMS * sizeof(unsigned long)); - cpu = first_cpu(*cpumask); - while (cpu < NR_CPUS) { + for_each_cpu_mask(cpu, *cpumask) { struct vm_event_state *this = &per_cpu(vm_event_states, cpu); - cpu = next_cpu(cpu, *cpumask); - - if (cpu < NR_CPUS) - prefetch(&per_cpu(vm_event_states, cpu)); - - for (i = 0; i < NR_VM_EVENT_ITEMS; i++) ret[i] += this->event[i]; } - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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