mm: remove migration for HugePage in isolate_single_pageblock()

The gigantic page size may larger than memory block size, so memory
offline always fails in this case after commit b2c9e2fbba32 ("mm: make
alloc_contig_range work at pageblock granularity"),

offline_pages
  start_isolate_page_range
    start_isolate_page_range(isolate_before=true)
      isolate [isolate_start, isolate_start + pageblock_nr_pages)
    start_isolate_page_range(isolate_before=false)
      isolate [isolate_end - pageblock_nr_pages, isolate_end) pageblock
       	__alloc_contig_migrate_range
          isolate_migratepages_range
            isolate_migratepages_block
              isolate_or_dissolve_huge_page
                if (hstate_is_gigantic(h))
                    return -ENOMEM;

[   15.815756] memory offlining [mem 0x3c0000000-0x3c7ffffff] failed due to failure to isolate range

Gigantic PageHuge is bigger than a pageblock, but since it is freed as
order-0 pages, its pageblocks after being freed will get to the right
free list.  There is no need to have special handling code for them in
start_isolate_page_range().  For both alloc_contig_range() and memory
offline cases, the migration code after start_isolate_page_range() will
be able to migrate gigantic PageHuge when possible.  Let's clean up
start_isolate_page_range() and fix the aforementioned memory offline
failure issue all together.

Let's clean up start_isolate_page_range() and fix the aforementioned
memory offline failure issue all together.

Link: https://lkml.kernel.org/r/20240820032630.1894770-1-wangkefeng.wang@huawei.com
Fixes: b2c9e2fbba32 ("mm: make alloc_contig_range work at pageblock granularity")
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Zi Yan <ziy@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index 39fb8c07aeb78ccd86e20c71e77ebb2e2aecc40a..7e04047977cfea54e860b80d992758f2daf7fe5d 100644 (file)
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -403,30 +403,8 @@ static int isolate_single_pageblock(unsigned long boundary_pfn, int flags,
                        unsigned long head_pfn = page_to_pfn(head);
                        unsigned long nr_pages = compound_nr(head);
 
-                       if (head_pfn + nr_pages <= boundary_pfn) {
-                               pfn = head_pfn + nr_pages;
-                               continue;
-                       }
-
-#if defined CONFIG_COMPACTION || defined CONFIG_CMA
-                       if (PageHuge(page)) {
-                               int page_mt = get_pageblock_migratetype(page);
-                               struct compact_control cc = {
-                                       .nr_migratepages = 0,
-                                       .order = -1,
-                                       .zone = page_zone(pfn_to_page(head_pfn)),
-                                       .mode = MIGRATE_SYNC,
-                                       .ignore_skip_hint = true,
-                                       .no_set_skip_hint = true,
-                                       .gfp_mask = gfp_flags,
-                                       .alloc_contig = true,
-                               };
-                               INIT_LIST_HEAD(&cc.migratepages);
-
-                               ret = __alloc_contig_migrate_range(&cc, head_pfn,
-                                                       head_pfn + nr_pages, page_mt);
-                               if (ret)
-                                       goto failed;
+                       if (head_pfn + nr_pages <= boundary_pfn ||
+                           PageHuge(page)) {
                                pfn = head_pfn + nr_pages;
                                continue;
                        }
@@ -440,7 +418,7 @@ static int isolate_single_pageblock(unsigned long boundary_pfn, int flags,
                         */
                        VM_WARN_ON_ONCE_PAGE(PageLRU(page), page);
                        VM_WARN_ON_ONCE_PAGE(__PageMovable(page), page);
-#endif
+
                        goto failed;
                }