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Mon, 19 Oct 2026 05:44:52 +0000 X-Mizu-Trace-ID: 48f0776ddb594f90 X-Migadu-Flow: FLOW_OUT From: Hao Ge To: Suren Baghdasaryan , Uladzislau Rezki , 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 Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-mm@kvack.org, Hao Ge Subject: [PATCH v2 5/5] mm/percpu: stop unmapping the CPU that failed to map Date: Mon, 19 Oct 2026 13:45:30 +0800 Message-Id: <20261019054531.87652-6-hao.ge@linux.dev> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20261019054531.87652-1-hao.ge@linux.dev> References: <20261019054531.87652-1-hao.ge@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: BA1F140005 X-Stat-Signature: j1xfdq9eco1k799xzquzaqmz377ao7mn X-Rspam-User: X-HE-Tag: 1792388693-597173 X-HE-Meta: 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 fa0J9b2B gRvUmJh4Efqxlm6xbsOZVeKIxl8RTIW2pASeakZ3BEbuZAolJNU9I/vpdF1IWtLN5ikE44mP+tDTMVh9tsOz2jnHqafa7CaXFZ6J7Mxqz8rbJaU7F/roltWoggsikt4tNTasDZ3ODDi/TAx/SbEXnAHXILvY3RZhELilPumlo0/gULqSsZhLc/gm7leesjPX0F7N3ZkFjN2y66+psm+LPToYaZd1dvpnFGDTEJVAJfjlgLn5P6+J6st5f8SPtNbXz4+ZKd/1QBuFED7nxTzH8oBhMzkInOpbopakUsKMdgasGQKfT/PHqq0pleQ4ESXQ6bH9G1ygYc4RfyuctH1BAXlpuPxlayJoNbLlB Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: __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