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Howlett" , "Liam R. Howlett" Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, Breno Leitao , linux-trace-kernel@vger.kernel.org, kernel-team@meta.com, Lance Yang X-Mailer: b4 0.16-dev-d5d98 X-Developer-Signature: v=1; a=openpgp-sha256; l=3194; i=leitao@debian.org; h=from:subject:message-id; bh=dRzYu8tKgN6EjEgu5H7QOpWd9i5LbDMZJK2X6dDuigk=; b=owEBbQKS/ZANAwAIATWjk5/8eHdtAcsmYgBqFvpb1t1yv21tSoXdpd9OeX7lVUqVxBfmBWhRO 7QMfvqcuUqJAjMEAAEIAB0WIQSshTmm6PRnAspKQ5s1o5Of/Hh3bQUCahb6WwAKCRA1o5Of/Hh3 bRLSD/9hra+31QED97u48QP55twrygQyNcmxlYKWygJmoyU4xa7l6enHBboEvlIJi7I/r2D8812 ZM1O1RL4Rl0bxPeX4dQDLD21S+aNapyrEP/X1Nc+z7O5xECZK1gAiTXa1ZDG/jna6TbAIT8iUKu 3c5LPqKasQzx6QwGZuf+PfZRicIkAxftwTNEdUB4+M74p8Jic0eGsydOMR23W0dzm75MsjGe39B wna0s/IXdcK1m7Qw4lpXQNdmbiWapHcmEUOqMezfMugMkUCiz8bgSfRRG7gLPG4EX1D5o2eNaMu itOnCL/dX/AUwCSE2eKiIMNZwf3Aey9zc6Msb3yVwKdRDxu0yLIHvUFQUI9jvIWRMjQu9fjNWOh yUUzXaDncvCoJA1LL1oVJzi/mEHe5YrHkLKOC6DMhYYMts7Cgj8s8OiXiGmngwT43XyL64x8VmO EHmlfnY9FVJY57gVvOP06yMEq6HJKpcHUD9mjcpdba4L24qncka7JHwbu0x1O7DOQSKi0M0IgDO +FZqA2sNAf4etbyVSm9aV6mCYLbt2jO3o0ItIeV3SpI+A40KNmuo1a8DcjrltK9R9NV+p3+dXvT WwZtY5lCZVJU/v+gePAT8u/k+VN1IZFPgWbIO4BcMcIw/zU4l1HWhqIFCsikew7x7FiAyA1/QKY 1Xr7zhi5EBlO9Cg== X-Developer-Key: i=leitao@debian.org; a=openpgp; fpr=AC8539A6E8F46702CA4A439B35A3939FFC78776D X-Debian-User: leitao X-Rspamd-Server: rspam11 X-Stat-Signature: o4ce1h7j7keranjcmpw7htaouw7h8j4f X-Rspamd-Queue-Id: 784ECA0016 X-Rspam-User: X-HE-Tag: 1779890800-508202 X-HE-Meta: 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 lmKGBK3N +9MHyti4Qv9I9U5aqDD8j5GHUeByf7C3fmwXmAY1kzVrokL1j1pURDDwqUD5rUneRr87y39iVcmfbTZP8OTjazMJWGuj0jmftBTCuurjD9cAF0TcdnSCMR8iQNtF6pLWuyGjsRxSDa8uNoJIPTWk4g1gruHRiy5q8j54aoChuNZAPyv01JOW4WtCXIt6IQt3Q1z4vXeWccAZ8ijIHqKyq4iiJ0QYDF/Juc6GcVyr84KZv+Q8M4wnmy//BW55coRuhttP7TOBo9p/z3hJNOjQ2HxtV4bRdGAZNKwf447MdUHqjRR5/5/Kclb420vbXWmefa0/jbID1q0ANd9EkHJidLiYur1GlSLkpha8XkXBdOvrEe9N69KL5FyBlhqqHRitnYPgMe8daX6nfy6XleoW9ydnjIygoJCUsUhmIUX6qNExa+mREoSvJM5elrmYyn9aasrpl1tlvArlKbC0= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: The first entry of error_states[], { reserved, reserved, MF_MSG_KERNEL, me_kernel }, is unreachable. identify_page_state() has two callers, and neither one can dispatch a PG_reserved page to me_kernel(): * memory_failure() reaches identify_page_state() only after get_hwpoison_page() returned 1. get_any_page() reaches that return only via __get_hwpoison_page(), which only takes a refcount when the page is HWPoisonHandlable(). HWPoisonHandlable() is an allowlist for LRU, free-buddy, and (for soft-offline) movable_ops pages -- PG_reserved pages do not satisfy any of these, so they fail with -EBUSY/-EIO long before identify_page_state() runs. * try_memory_failure_hugetlb() reaches identify_page_state() only via the MF_HUGETLB_IN_USED branch, where the page is necessarily a hugetlb folio. hugetlb folios don't carry PG_reserved at that point: hugetlb_folio_init_vmemmap() calls __folio_clear_reserved() during init, so the reserved entry would not match even if it were still present. me_kernel() never executes and the entry exists only to be matched against by code that cannot see it. Drop the entry, the me_kernel() helper, and the now-unused "reserved" macro. Leave the MF_MSG_KERNEL enum value in place: it remains part of the tracepoint and pr_err() string tables, and follow-on work to classify unrecoverable kernel pages can reuse it without churning the user-visible enum. No functional change. Suggested-by: David Hildenbrand Acked-by: David Hildenbrand (Arm) Reviewed-by: Lance Yang Acked-by: Miaohe Lin Signed-off-by: Breno Leitao --- mm/memory-failure.c | 14 -------------- 1 file changed, 14 deletions(-) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 51508a55c405..f4d3e6e20e13 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -980,17 +980,6 @@ static bool has_extra_refcount(struct page_state *ps, struct page *p, return false; } -/* - * Error hit kernel page. - * Do nothing, try to be lucky and not touch this instead. For a few cases we - * could be more sophisticated. - */ -static int me_kernel(struct page_state *ps, struct page *p) -{ - unlock_page(p); - return MF_IGNORED; -} - /* * Page in unknown state. Do nothing. * This is a catch-all in case we fail to make sense of the page state. @@ -1199,10 +1188,8 @@ static int me_huge_page(struct page_state *ps, struct page *p) #define mlock (1UL << PG_mlocked) #define lru (1UL << PG_lru) #define head (1UL << PG_head) -#define reserved (1UL << PG_reserved) static struct page_state error_states[] = { - { reserved, reserved, MF_MSG_KERNEL, me_kernel }, /* * free pages are specially detected outside this table: * PG_buddy pages only make a small fraction of all free pages. @@ -1234,7 +1221,6 @@ static struct page_state error_states[] = { #undef mlock #undef lru #undef head -#undef reserved static void update_per_node_mf_stats(unsigned long pfn, enum mf_result result) -- 2.54.0