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Tue, 10 Nov 2026 11:25:41 +0000 X-Mizu-Trace-ID: 0846a03f7f9c0cfe X-Migadu-Flow: FLOW_OUT From: Hao Ge To: Uladzislau Rezki , Dev Jain , Suren Baghdasaryan , Andrew Morton , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , "Christophe Leroy (CS GROUP)" , "Ritesh Harjani (IBM)" , Shrikanth Hegde , Alexander Potapenko , Marco Elver , Dmitry Vyukov , Dennis Zhou , Tejun Heo , Christoph Lameter Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-mm@kvack.org, Hao Ge Subject: [PATCH v4 9/9] mm/percpu: stop unmapping the CPU that failed to map Date: Tue, 10 Nov 2026 19:25:46 +0800 Message-Id: <20261110112546.261415-10-hao.ge@linux.dev> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20261110112546.261415-1-hao.ge@linux.dev> References: <20261110112546.261415-1-hao.ge@linux.dev> X-Archived-By: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Stat-Signature: f8nki1ntpofr8fxfyhf5n64c5h7ibz5o X-Rspamd-Queue-Id: F38F7100006 X-Rspam-User: X-Rspamd-Server: rspam11 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-HE-Tag: 1794309952-265019 X-HE-Meta: U2FsdGVkX18Zn1mNWj24IEkUYrWJiqO8zc4VVWDQAeoMCci86arTuNIbtixTOU+GZYes3uOBKW+bVrgCdpqspiZhcI8euZ4MUcBgBB1KVKZc/fS2d2AdrnSRUDSdfGU7tgKfaQeLrBhfZuCTrVw3/Xo19QefmUZCkQL1IqYwgXu+YGKGjpO3HGif2XgvaiqMp2wFwO/Qk5NESu8n1xg+tDlAnxeUeEBxi6DogN7+qVXgxwNik8iYShAghUQqF8V9PhKwDtVCj7LIsHLZU4HtuCMiKSk1j9eOT8OqDQMMvNH4N7FMD+bsqETkv2SdogUYWtqNLf72vOiIVD+BDcDUrYvX/KElDyaQ7OD/VONFS/oPb/0xk0R3/7qd9vLiq4wO4Xj4gZ45uDN02SFJxHT4D2j/Yop91VJ+/b9caRjbKKZjQTvrgOhd2AhS8xTB++ZqHx6DLGQGsa5eQlRY9q81CGuNBR2FcMgTfzXTSgUI39xGkD5VMcf2kxUOXNAxXei7Si/lP6G0N3JQ61be/HmUm19zd6eFGRNRldaMWYqdoJK++uxi/8jRxSP8ParfKYYv/8tjkUbofhncE97fCtu3JjPgBe41LZvqaX6jNy/rYa19z2nocSSaUDm6wFM0f/DlHDdrljrGUG6E72iV8LbGhsaTzpvjCPr0ldKJSoRTln/rBM/zlYrFKSiJbX6ak6wqyB8OP7W1siUxYL7uNz6pEST1++h1WsKovmPgZ4dGf0Yx9vZd9Vc5bUj2ruE987q3jS8XuE8dZ8D7ABAzJwg46zb9ckD+0YlS7g/AyOtdzcaYXwjE9T17vKkoejsdv75dIhswQhyeRPxIrdXVnbit8FMtrR6ufbF2vLoboXexkyB1+8D20Or0gVA52lN8ZdzAUhDcHKCqKXSsjeoMKsBPx8SCeBQMCRNda4PATJC6lRJZ8WweJK3DROne8Wo+4iK2huI4h37Sc7vhu7j0GRA /ZtVQMjX MCRfZ+qogn0OGGWjN5m73Yn3kFGDSyS8ZRUjBY8cw85hCOXr2GIzD284UsOfu7KlMrfQ8cj8rPLTsNzGKQXKUU4yqMqDFUMmSxL0yEbpcgJOjMTSyHG331/rwFcvkn+dup3cMvdTF/stiiUnAq3vPxg1QyX4gyFhzcwdJeEI3AW29hx4jKqy/BbKghOJXk8NLHTdmqrbe/HKZzkwy006IkW787LadUfI+ZWp22hmK+8SEr0HtSep9KB3w90xoDrW0OvENTBcA8XB4e50jcqYn75ICpuQIyYSfb4fbwRtISTzbLyQLszb8vGlqQVXX2gJxySF2uZC6dANInV9kjWQG0Ga8G0zREsvtiarH 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