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a458431e17
Commit702d1a6e07
("memory-hotplug: fix kswapd looping forever problem") added an isolated pageblocks counter (nr_pageblock_isolate in struct zone) and used it to adjust free pages counter in zone_watermark_ok_safe() to prevent kswapd looping forever problem. Then later, commit2139cbe627
("cma: fix counting of isolated pages") fixed accounting of isolated pages in global free pages counter. It made the previous zone_watermark_ok_safe() fix unnecessary and potentially harmful (cause now isolated pages may be accounted twice making free pages counter incorrect). This patch removes the special isolated pageblocks counter altogether which fixes zone_watermark_ok_safe() free pages check. Reported-by: Tomasz Stanislawski <t.stanislaws@samsung.com> Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Cc: Minchan Kim <minchan@kernel.org> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Aaditya Kumar <aaditya.kumar.30@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@suse.cz> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
260 lines
7.0 KiB
C
260 lines
7.0 KiB
C
/*
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* linux/mm/page_isolation.c
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*/
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#include <linux/mm.h>
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#include <linux/page-isolation.h>
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#include <linux/pageblock-flags.h>
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#include <linux/memory.h>
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#include "internal.h"
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int set_migratetype_isolate(struct page *page, bool skip_hwpoisoned_pages)
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{
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struct zone *zone;
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unsigned long flags, pfn;
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struct memory_isolate_notify arg;
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int notifier_ret;
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int ret = -EBUSY;
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zone = page_zone(page);
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spin_lock_irqsave(&zone->lock, flags);
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pfn = page_to_pfn(page);
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arg.start_pfn = pfn;
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arg.nr_pages = pageblock_nr_pages;
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arg.pages_found = 0;
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/*
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* It may be possible to isolate a pageblock even if the
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* migratetype is not MIGRATE_MOVABLE. The memory isolation
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* notifier chain is used by balloon drivers to return the
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* number of pages in a range that are held by the balloon
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* driver to shrink memory. If all the pages are accounted for
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* by balloons, are free, or on the LRU, isolation can continue.
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* Later, for example, when memory hotplug notifier runs, these
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* pages reported as "can be isolated" should be isolated(freed)
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* by the balloon driver through the memory notifier chain.
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*/
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notifier_ret = memory_isolate_notify(MEM_ISOLATE_COUNT, &arg);
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notifier_ret = notifier_to_errno(notifier_ret);
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if (notifier_ret)
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goto out;
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/*
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* FIXME: Now, memory hotplug doesn't call shrink_slab() by itself.
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* We just check MOVABLE pages.
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*/
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if (!has_unmovable_pages(zone, page, arg.pages_found,
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skip_hwpoisoned_pages))
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ret = 0;
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/*
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* immobile means "not-on-lru" paes. If immobile is larger than
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* removable-by-driver pages reported by notifier, we'll fail.
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*/
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out:
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if (!ret) {
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unsigned long nr_pages;
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int migratetype = get_pageblock_migratetype(page);
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set_pageblock_migratetype(page, MIGRATE_ISOLATE);
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nr_pages = move_freepages_block(zone, page, MIGRATE_ISOLATE);
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__mod_zone_freepage_state(zone, -nr_pages, migratetype);
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}
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spin_unlock_irqrestore(&zone->lock, flags);
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if (!ret)
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drain_all_pages();
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return ret;
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}
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void unset_migratetype_isolate(struct page *page, unsigned migratetype)
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{
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struct zone *zone;
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unsigned long flags, nr_pages;
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zone = page_zone(page);
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spin_lock_irqsave(&zone->lock, flags);
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if (get_pageblock_migratetype(page) != MIGRATE_ISOLATE)
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goto out;
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nr_pages = move_freepages_block(zone, page, migratetype);
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__mod_zone_freepage_state(zone, nr_pages, migratetype);
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set_pageblock_migratetype(page, migratetype);
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out:
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spin_unlock_irqrestore(&zone->lock, flags);
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}
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static inline struct page *
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__first_valid_page(unsigned long pfn, unsigned long nr_pages)
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{
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int i;
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for (i = 0; i < nr_pages; i++)
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if (pfn_valid_within(pfn + i))
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break;
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if (unlikely(i == nr_pages))
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return NULL;
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return pfn_to_page(pfn + i);
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}
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/*
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* start_isolate_page_range() -- make page-allocation-type of range of pages
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* to be MIGRATE_ISOLATE.
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* @start_pfn: The lower PFN of the range to be isolated.
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* @end_pfn: The upper PFN of the range to be isolated.
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* @migratetype: migrate type to set in error recovery.
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*
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* Making page-allocation-type to be MIGRATE_ISOLATE means free pages in
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* the range will never be allocated. Any free pages and pages freed in the
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* future will not be allocated again.
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*
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* start_pfn/end_pfn must be aligned to pageblock_order.
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* Returns 0 on success and -EBUSY if any part of range cannot be isolated.
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*/
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int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
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unsigned migratetype, bool skip_hwpoisoned_pages)
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{
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unsigned long pfn;
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unsigned long undo_pfn;
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struct page *page;
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BUG_ON((start_pfn) & (pageblock_nr_pages - 1));
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BUG_ON((end_pfn) & (pageblock_nr_pages - 1));
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for (pfn = start_pfn;
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pfn < end_pfn;
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pfn += pageblock_nr_pages) {
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page = __first_valid_page(pfn, pageblock_nr_pages);
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if (page &&
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set_migratetype_isolate(page, skip_hwpoisoned_pages)) {
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undo_pfn = pfn;
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goto undo;
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}
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}
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return 0;
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undo:
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for (pfn = start_pfn;
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pfn < undo_pfn;
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pfn += pageblock_nr_pages)
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unset_migratetype_isolate(pfn_to_page(pfn), migratetype);
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return -EBUSY;
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}
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/*
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* Make isolated pages available again.
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*/
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int undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
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unsigned migratetype)
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{
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unsigned long pfn;
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struct page *page;
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BUG_ON((start_pfn) & (pageblock_nr_pages - 1));
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BUG_ON((end_pfn) & (pageblock_nr_pages - 1));
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for (pfn = start_pfn;
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pfn < end_pfn;
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pfn += pageblock_nr_pages) {
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page = __first_valid_page(pfn, pageblock_nr_pages);
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if (!page || get_pageblock_migratetype(page) != MIGRATE_ISOLATE)
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continue;
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unset_migratetype_isolate(page, migratetype);
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}
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return 0;
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}
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/*
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* Test all pages in the range is free(means isolated) or not.
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* all pages in [start_pfn...end_pfn) must be in the same zone.
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* zone->lock must be held before call this.
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*
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* Returns 1 if all pages in the range are isolated.
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*/
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static int
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__test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn,
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bool skip_hwpoisoned_pages)
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{
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struct page *page;
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while (pfn < end_pfn) {
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if (!pfn_valid_within(pfn)) {
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pfn++;
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continue;
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}
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page = pfn_to_page(pfn);
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if (PageBuddy(page)) {
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/*
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* If race between isolatation and allocation happens,
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* some free pages could be in MIGRATE_MOVABLE list
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* although pageblock's migratation type of the page
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* is MIGRATE_ISOLATE. Catch it and move the page into
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* MIGRATE_ISOLATE list.
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*/
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if (get_freepage_migratetype(page) != MIGRATE_ISOLATE) {
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struct page *end_page;
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end_page = page + (1 << page_order(page)) - 1;
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move_freepages(page_zone(page), page, end_page,
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MIGRATE_ISOLATE);
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}
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pfn += 1 << page_order(page);
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}
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else if (page_count(page) == 0 &&
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get_freepage_migratetype(page) == MIGRATE_ISOLATE)
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pfn += 1;
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else if (skip_hwpoisoned_pages && PageHWPoison(page)) {
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/*
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* The HWPoisoned page may be not in buddy
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* system, and page_count() is not 0.
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*/
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pfn++;
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continue;
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}
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else
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break;
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}
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if (pfn < end_pfn)
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return 0;
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return 1;
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}
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int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn,
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bool skip_hwpoisoned_pages)
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{
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unsigned long pfn, flags;
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struct page *page;
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struct zone *zone;
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int ret;
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/*
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* Note: pageblock_nr_page != MAX_ORDER. Then, chunks of free page
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* is not aligned to pageblock_nr_pages.
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* Then we just check pagetype fist.
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*/
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for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
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page = __first_valid_page(pfn, pageblock_nr_pages);
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if (page && get_pageblock_migratetype(page) != MIGRATE_ISOLATE)
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break;
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}
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page = __first_valid_page(start_pfn, end_pfn - start_pfn);
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if ((pfn < end_pfn) || !page)
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return -EBUSY;
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/* Check all pages are free or Marked as ISOLATED */
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zone = page_zone(page);
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spin_lock_irqsave(&zone->lock, flags);
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ret = __test_page_isolated_in_pageblock(start_pfn, end_pfn,
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skip_hwpoisoned_pages);
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spin_unlock_irqrestore(&zone->lock, flags);
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return ret ? 0 : -EBUSY;
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}
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struct page *alloc_migrate_target(struct page *page, unsigned long private,
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int **resultp)
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{
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gfp_t gfp_mask = GFP_USER | __GFP_MOVABLE;
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if (PageHighMem(page))
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gfp_mask |= __GFP_HIGHMEM;
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return alloc_page(gfp_mask);
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}
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