Commit 0dcc48c15f63ee86c2fcd33968b08d651f0360a5
Committed by
Linus Torvalds
Linus Torvalds
1 parent
bc69304574
Exists in
master
and in
20 other branches
memory hotplug: fix next block calculation in is_removable
next_active_pageblock() is for finding next _used_ freeblock. It skips several blocks when it finds there are a chunk of free pages lager than pageblock. But it has 2 bugs. 1. We have no lock. page_order(page) - pageblock_order can be minus. 2. pageblocks_stride += is wrong. it should skip page_order(p) of pages. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Showing 1 changed file with 8 additions and 8 deletions Side-by-side Diff
mm/memory_hotplug.c
| ... | ... | @@ -584,19 +584,19 @@ |
| 584 | 584 | /* Return the start of the next active pageblock after a given page */ |
| 585 | 585 | static struct page *next_active_pageblock(struct page *page) |
| 586 | 586 | { |
| 587 | - int pageblocks_stride; | |
| 588 | - | |
| 589 | 587 | /* Ensure the starting page is pageblock-aligned */ |
| 590 | 588 | BUG_ON(page_to_pfn(page) & (pageblock_nr_pages - 1)); |
| 591 | 589 | |
| 592 | - /* Move forward by at least 1 * pageblock_nr_pages */ | |
| 593 | - pageblocks_stride = 1; | |
| 594 | - | |
| 595 | 590 | /* If the entire pageblock is free, move to the end of free page */ |
| 596 | - if (pageblock_free(page)) | |
| 597 | - pageblocks_stride += page_order(page) - pageblock_order; | |
| 591 | + if (pageblock_free(page)) { | |
| 592 | + int order; | |
| 593 | + /* be careful. we don't have locks, page_order can be changed.*/ | |
| 594 | + order = page_order(page); | |
| 595 | + if ((order < MAX_ORDER) && (order >= pageblock_order)) | |
| 596 | + return page + (1 << order); | |
| 597 | + } | |
| 598 | 598 | |
| 599 | - return page + (pageblocks_stride * pageblock_nr_pages); | |
| 599 | + return page + pageblock_nr_pages; | |
| 600 | 600 | } |
| 601 | 601 | |
| 602 | 602 | /* Checks if this range of memory is likely to be hot-removable. */ |