On Wed, 9 May 2007, Yasunori Goto wrote:
Isolate all freed pages (means in buddy_list) in the range.
See page_buddy() and free_one_page() function if unsure.
Signed-Off-By: KAMEZAWA Hiroyuki <[email protected]>
Signed-off-by: Yasunori Goto <[email protected]>
include/linux/page_isolation.h | 1
mm/page_alloc.c | 45 +++++++++++++++++++++++++++++++++++++++++
2 files changed, 46 insertions(+)
Index: current_test/mm/page_alloc.c
===================================================================
--- current_test.orig/mm/page_alloc.c 2007-05-08 15:08:04.000000000 +0900
+++ current_test/mm/page_alloc.c 2007-05-08 15:08:26.000000000 +0900
@@ -4411,6 +4411,51 @@ free_all_isolated_pages(struct isolation
}
}
+/*
+ * Isolate already freed pages.
+ */
+int
+capture_isolate_freed_pages(struct isolation_info *info)
+{
+ struct zone *zone;
+ unsigned long pfn;
+ struct page *page;
+ int order, order_size;
+ int nr_pages = 0;
+ unsigned long last_pfn = info->end_pfn - 1;
+ pfn = info->start_pfn;
+ if (!pfn_valid(pfn))
+ return -EINVAL;
This may lead to boundary cases where pages cannot be captured at the
start and end of non-aligned zones due to memory holes.
+ zone = info->zone;
+ if ((zone != page_zone(pfn_to_page(pfn))) ||
+ (zone != page_zone(pfn_to_page(last_pfn))))
+ return -EINVAL;
Is this check really necessary? Surely a caller to
capture_isolate_freed_pages() will have already made all the necessary
checks when adding the struct insolation_info ?
+ drain_all_pages();
+ spin_lock(&zone->lock);
+ while (pfn < info->end_pfn) {
+ if (!pfn_valid(pfn)) {
+ pfn++;
+ continue;
+ }
+ page = pfn_to_page(pfn);
+ /* See page_is_buddy() */
+ if (page_count(page) == 0 && PageBuddy(page)) {
If PageBuddy is set it's free, you shouldn't have to check the page_count.
+ order = page_order(page);
+ order_size = 1 << order;
+ zone->free_area[order].nr_free--;
+ __mod_zone_page_state(zone, NR_FREE_PAGES, -order_size);
+ list_del(&page->lru);
+ rmv_page_order(page);
+ isolate_page_nolock(info, page, order);
+ nr_pages += order_size;
+ pfn += order_size;
+ } else {
+ pfn++;
+ }
+ }
+ spin_unlock(&zone->lock);
+ return nr_pages;
+}
#endif /* CONFIG_PAGE_ISOLATION */
This is all similar to move_freepages() other than the locking part. It
would be worth checking if there is code that could be shared or at least
have similar styles.
Index: current_test/include/linux/page_isolation.h
===================================================================
--- current_test.orig/include/linux/page_isolation.h 2007-05-08 15:08:04.000000000 +0900
+++ current_test/include/linux/page_isolation.h 2007-05-08 15:08:27.000000000 +0900
@@ -40,6 +40,7 @@ extern void free_isolation_info(struct i
extern void unuse_all_isolated_pages(struct isolation_info *info);
extern void free_all_isolated_pages(struct isolation_info *info);
extern void drain_all_pages(void);
+extern int capture_isolate_freed_pages(struct isolation_info *info);
#else
--
Yasunori Goto
--
Mel Gorman
Part-time Phd Student Linux Technology Center
University of Limerick IBM Dublin Software Lab
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