On 2013/5/24 17:30, Tang Chen wrote:
> In memory offline procedure, skip pages marked as LOCAL_NODE_DATA.
> For now, this kind of pages are used to store local node pagetables.
>
> The minimum unit of memory online/offline is a memory block. In a
> block, the movable pages will be offlined as usual (unmapped and
> isolated), and the pagetable pages will be skipped. After the iteration
> of all page, the block will be set as offline, but the kernel can
> still access the pagetable pages. This is user transparent.
>
> Signed-off-by: Tang Chen <tangchen@xxxxxxxxxxxxxx>
> ---
> mm/page_alloc.c | 18 ++++++++++++++++--
> mm/page_isolation.c | 6 ++++++
> 2 files changed, 22 insertions(+), 2 deletions(-)
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 557b21b..73b8f0b 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -5701,11 +5701,18 @@ bool has_unmovable_pages(struct zone *zone, struct page *page, int count,
> pfn = page_to_pfn(page);
> for (found = 0, iter = 0; iter < pageblock_nr_pages; iter++) {
> unsigned long check = pfn + iter;
> + unsigned long magic;
>
> if (!pfn_valid_within(check))
> continue;
>
> page = pfn_to_page(check);
> +
> + /* Skip pages storing local node kernel data. */
> + magic = (unsigned long)page->lru.next;
> + if (magic == LOCAL_NODE_DATA)
Hi Tang,
I think can define this as a macro, and can be reused in the other places.
Thanks,
Jianguo Wu.
> + continue;
> +
> /*
> * We can't use page_count without pin a page
> * because another CPU can free compound page.
> @@ -6029,8 +6036,7 @@ __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
> struct page *page;
> struct zone *zone;
> int order, i;
> - unsigned long pfn;
> - unsigned long flags;
> + unsigned long pfn, flags, magic;
> /* find the first valid pfn */
> for (pfn = start_pfn; pfn < end_pfn; pfn++)
> if (pfn_valid(pfn))
> @@ -6046,6 +6052,14 @@ __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
> continue;
> }
> page = pfn_to_page(pfn);
> +
> + /* Skip pages storing local node kernel data. */
> + magic = (unsigned long)page->lru.next;
> + if (magic == LOCAL_NODE_DATA) {
> + pfn++;
> + continue;
> + }
> +
> /*
> * The HWPoisoned page may be not in buddy system, and
> * page_count() is not 0.
> diff --git a/mm/page_isolation.c b/mm/page_isolation.c
> index 383bdbb..fb60a27 100644
> --- a/mm/page_isolation.c
> +++ b/mm/page_isolation.c
> @@ -174,6 +174,7 @@ __test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn,
> bool skip_hwpoisoned_pages)
> {
> struct page *page;
> + unsigned long magic;
>
> while (pfn < end_pfn) {
> if (!pfn_valid_within(pfn)) {
> @@ -181,6 +182,8 @@ __test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn,
> continue;
> }
> page = pfn_to_page(pfn);
> + magic = (unsigned long)page->lru.next;
> +
> if (PageBuddy(page)) {
> /*
> * If race between isolatation and allocation happens,
> @@ -208,6 +211,9 @@ __test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn,
> */
> pfn++;
> continue;
> + } else if (magic == LOCAL_NODE_DATA) {
> + pfn++;
> + continue;
> }
> else
> break;
--
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