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Mon, 26 Oct 2026 08:03:25 +0000 X-Mizu-Trace-ID: 63343c3c8e1494da X-Migadu-Flow: FLOW_OUT From: Hao Ge To: Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , "Christophe Leroy (CS GROUP)" , "Ritesh Harjani (IBM)" , Shrikanth Hegde , Alexander Potapenko , Marco Elver , Dmitry Vyukov , Andrew Morton , Dennis Zhou , Tejun Heo , Christoph Lameter , Uladzislau Rezki , Hao Ge , Suren Baghdasaryan , Dev Jain Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-mm@kvack.org Subject: [PATCH v3 10/10] mm/percpu: stop unmapping the CPU that failed to map Date: Mon, 26 Oct 2026 16:03:29 +0800 Message-Id: <20261026080329.140244-11-hao.ge@linux.dev> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20261026080329.140244-1-hao.ge@linux.dev> References: <20261026080329.140244-1-hao.ge@linux.dev> X-Archived-By: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 6D09840005 X-Rspam-User: X-Stat-Signature: pxahzpstu1j8drwegkbo3o5r3zrn4skw X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=4.0.1 X-Rspamd-Server: rspam03 X-HE-Tag: 1793001807-690207 X-HE-Meta: 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 vzq7BAZ2 UlWR0DKuLUmOMdL4nakOmPD5crlyCMiuf6Dp+MOZwWlRq+lDJA7op3GpLGp6uSmpSkOy5pA3HEN1ZdF51L6P+qNu3uXjqL53EJ43hPISVfTejL+E5+z45MgMrpagJK/tQRrYWsZKjjQ6SeYcw9BPHG6evIUn2ZoePLAcBSHbL7PzzSsHCmv41h+BzbfFacTVd8zYWiApg5NBVSwyp9jvG4XXQEPkkA5Cyqp3ftAfhiwf+ZL1zz1eDljSE5epIryffF7RowASX8/6nU+T9b0exl3YmMAseMlaFKc8d2xwV3AMgQtVRSSwlveXvmloZPnlUwsPmq8nATbSgFm0AEnxmj3U3eWHEM7FuFgLc Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 __pcpu_map_pages() clears the PTEs it installed when it fails, so pcpu_map_pages() only has to tear down the CPUs it mapped before the failing one. Reviewed-by: Suren Baghdasaryan Reviewed-by: Uladzislau Rezki (Sony) Signed-off-by: Hao Ge --- mm/percpu-vm.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/mm/percpu-vm.c b/mm/percpu-vm.c index 509d8901835c..59d3a336a6bd 100644 --- a/mm/percpu-vm.c +++ b/mm/percpu-vm.c @@ -252,10 +252,11 @@ static int pcpu_map_pages(struct pcpu_chunk *chunk, struct page **pages, return 0; err: for_each_possible_cpu(tcpu) { - __pcpu_unmap_pages(pcpu_chunk_addr(chunk, tcpu, page_start), - page_end - page_start); + /* The failing CPU's partial mapping undoes itself */ if (tcpu == cpu) break; + __pcpu_unmap_pages(pcpu_chunk_addr(chunk, tcpu, page_start), + page_end - page_start); } pcpu_post_unmap_tlb_flush(chunk, page_start, page_end); return err; -- 2.25.1