diff options
| author | Kaitao Cheng <chengkaitao@kylinos.cn> | 2026-05-14 16:57:54 +0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2026-05-28 21:31:19 -0700 |
| commit | 44ce36456cd5fccbf10d8fbc4da61977bfcdb635 (patch) | |
| tree | 6ff62faea80302d4d4d9188876596f3dedb65cbb /mm | |
| parent | dfc528020988d1e56caec322968c7136a297a660 (diff) | |
| download | linux-next-history-44ce36456cd5fccbf10d8fbc4da61977bfcdb635.tar.gz | |
mm/memory-failure: use zone_pcp_disable() for poison handling
__page_handle_poison() used drain_all_pages() instead of
zone_pcp_disable() because dissolve_free_hugetlb_folio() could restore HVO
vmemmap pages and decrement hugetlb_optimize_vmemmap_key. That static key
update took cpu_hotplug_lock through static_key_slow_dec(), while
zone_pcp_disable() holds pcp_batch_high_lock. CPU hotplug takes the locks
in the opposite order through page_alloc_cpu_online/dead(), so the
combination could deadlock.
That dependency no longer exists. Commit da3e2d1ca43d ("mm/hugetlb:
remove hugetlb_optimize_vmemmap_key static key") removed the HVO static
key and the static_branch_dec() from hugetlb_vmemmap_restore_folio(). The
dissolve_free_hugetlb_folio() path no longer reaches
static_key_slow_dec().
Use zone_pcp_disable() again while dissolving the hugetlb folio and taking
the target page off the buddy allocator. This prevents the drained PCP
lists from being refilled before take_page_off_buddy() runs, making the
page isolation deterministic.
Link: https://lore.kernel.org/20260514085754.84097-1-kaitao.cheng@linux.dev
Signed-off-by: Kaitao Cheng <chengkaitao@kylinos.cn>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/memory-failure.c | 18 |
1 files changed, 3 insertions, 15 deletions
diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 1b8d0bade04a7..51508a55c4055 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -172,23 +172,11 @@ static int __page_handle_poison(struct page *page) { int ret; - /* - * zone_pcp_disable() can't be used here. It will - * hold pcp_batch_high_lock and dissolve_free_hugetlb_folio() might hold - * cpu_hotplug_lock via static_key_slow_dec() when hugetlb vmemmap - * optimization is enabled. This will break current lock dependency - * chain and leads to deadlock. - * Disabling pcp before dissolving the page was a deterministic - * approach because we made sure that those pages cannot end up in any - * PCP list. Draining PCP lists expels those pages to the buddy system, - * but nothing guarantees that those pages do not get back to a PCP - * queue if we need to refill those. - */ + zone_pcp_disable(page_zone(page)); ret = dissolve_free_hugetlb_folio(page_folio(page)); - if (!ret) { - drain_all_pages(page_zone(page)); + if (!ret) ret = take_page_off_buddy(page); - } + zone_pcp_enable(page_zone(page)); return ret; } |