At 07/05/2012 05:45 PM, Jiang Liu Wrote:
> When a zone becomes empty after memory offlining, free zone->pageset.
> Otherwise it will cause memory leak when adding memory to the empty
> zone again because build_all_zonelists() will allocate zone->pageset
> for an empty zone.
>
> Signed-off-by: Jiang Liu <liu...@gmail.com>
> Signed-off-by: Wei Wang <bessel.w...@huawei.com>
> ---
> include/linux/mm.h | 1 +
> mm/memory_hotplug.c | 3 +++
> mm/page_alloc.c | 13 +++++++++++++
> 3 files changed, 17 insertions(+), 0 deletions(-)
>
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index b36d08c..f8b62f2 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -1331,6 +1331,7 @@ void warn_alloc_failed(gfp_t gfp_mask, int order, const
> char *fmt, ...);
> extern void setup_per_cpu_pageset(void);
>
> extern void zone_pcp_update(struct zone *zone);
> +extern void zone_pcp_reset(struct zone *zone);
>
> /* nommu.c */
> extern atomic_long_t mmap_pages_allocated;
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index bce80c7..998b792 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -966,6 +966,9 @@ repeat:
>
> init_per_zone_wmark_min();
>
> + if (!populated_zone(zone))
> + zone_pcp_reset(zone);
> +
> if (!node_present_pages(node)) {
> node_clear_state(node, N_HIGH_MEMORY);
> kswapd_stop(node);
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index ebf319d..5964b7a 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -5872,6 +5872,19 @@ void free_contig_range(unsigned long pfn, unsigned
> nr_pages)
> #endif
>
> #ifdef CONFIG_MEMORY_HOTREMOVE
> +void zone_pcp_reset(struct zone *zone)
> +{
> + unsigned long flags;
> +
> + /* avoid races with drain_pages() */
> + local_irq_save(flags);
drain_pages() may run on another cpu, so it cann't avoid
races with drain_pages().
Thanks
Wen Congyang
> + if (zone->pageset != &boot_pageset) {
> + free_percpu(zone->pageset);
> + zone->pageset = &boot_pageset;
> + }
> + local_irq_restore(flags);
> +}
> +
> /*
> * All pages in the range must be isolated before calling this.
> */
--
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