diff options
| author | Qian Cai <cai@lca.pw> | 2019-03-28 20:43:34 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-03-29 10:01:37 -0700 |
| commit | 9b7ea46a82b31c74a37e6ff1c2a1df7d53e392ab (patch) | |
| tree | 2cb350d34d5fa97854324511572bb38d6b2c474d /include/linux/page-isolation.h | |
| parent | 73601ea5b7b18eb234219ae2adf77530f389da79 (diff) | |
mm/hotplug: fix offline undo_isolate_page_range()
Commit f1dd2cd13c4b ("mm, memory_hotplug: do not associate hotadded
memory to zones until online") introduced move_pfn_range_to_zone() which
calls memmap_init_zone() during onlining a memory block.
memmap_init_zone() will reset pagetype flags and makes migrate type to
be MOVABLE.
However, in __offline_pages(), it also call undo_isolate_page_range()
after offline_isolated_pages() to do the same thing. Due to commit
2ce13640b3f4 ("mm: __first_valid_page skip over offline pages") changed
__first_valid_page() to skip offline pages, undo_isolate_page_range()
here just waste CPU cycles looping around the offlining PFN range while
doing nothing, because __first_valid_page() will return NULL as
offline_isolated_pages() has already marked all memory sections within
the pfn range as offline via offline_mem_sections().
Also, after calling the "useless" undo_isolate_page_range() here, it
reaches the point of no returning by notifying MEM_OFFLINE. Those pages
will be marked as MIGRATE_MOVABLE again once onlining. The only thing
left to do is to decrease the number of isolated pageblocks zone counter
which would make some paths of the page allocation slower that the above
commit introduced.
Even if alloc_contig_range() can be used to isolate 16GB-hugetlb pages
on ppc64, an "int" should still be enough to represent the number of
pageblocks there. Fix an incorrect comment along the way.
[cai@lca.pw: v4]
Link: http://lkml.kernel.org/r/20190314150641.59358-1-cai@lca.pw
Link: http://lkml.kernel.org/r/20190313143133.46200-1-cai@lca.pw
Fixes: 2ce13640b3f4 ("mm: __first_valid_page skip over offline pages")
Signed-off-by: Qian Cai <cai@lca.pw>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org> [4.13+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/page-isolation.h')
| -rw-r--r-- | include/linux/page-isolation.h | 10 |
1 files changed, 0 insertions, 10 deletions
diff --git a/include/linux/page-isolation.h b/include/linux/page-isolation.h index 4eb26d278046..280ae96dc4c3 100644 --- a/include/linux/page-isolation.h +++ b/include/linux/page-isolation.h @@ -41,16 +41,6 @@ int move_freepages_block(struct zone *zone, struct page *page, /* * Changes migrate type in [start_pfn, end_pfn) to be MIGRATE_ISOLATE. - * If specified range includes migrate types other than MOVABLE or CMA, - * this will fail with -EBUSY. - * - * For isolating all pages in the range finally, the caller have to - * free all pages in the range. test_page_isolated() can be used for - * test it. - * - * The following flags are allowed (they can be combined in a bit mask) - * SKIP_HWPOISON - ignore hwpoison pages - * REPORT_FAILURE - report details about the failure to isolate the range */ int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn, |