From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta1.migadu.com (out-154.mta1.migadu.com [95.215.58.154]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A137047F77E for ; Mon, 19 Oct 2026 05:44:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.154 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792388750; cv=none; b=HlnaAx7CjLIGyexxCf7mkmFDuFTyClwbRfRbteOVJf6RvF+QgueGbiBjlwTtxKm9LnVeizz/MEj+5MyF/L1bBwWYMh0CaU+itxHn29ky4UroK4hosUSyaz2fTjy9+Hta7XsJzo/U9jaH+v6BSyOVJi6jwMqJmgcgjpSlb0RUzlE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792388750; c=relaxed/simple; bh=5qs+zHZlkyqRDMqx7SNWEDLyLXIGQ6DciwEgGF1OF3Y=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=r8FDQZ1EXoMW7kf47h4w5GAOidqSPwWRWa9h2cTcZxPFvNhd17TE+//9Tj7NM2zppiBzwR25q3izjMoIb3G54kKom0E5PwEyRfLaeVLSFexGjQxMWH9VpHKRFvE4ATaMerCmKHr0wDqpEMhLjw/9bRfP7eaB2X0A0T7pLJ8nm5A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=MtTMn6YA; arc=none smtp.client-ip=95.215.58.154 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="MtTMn6YA" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=5qs+zHZlkyqRDMqx7SNWEDLyLXIGQ6DciwEgGF1OF3Y=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1792388692; v=1; x=1792993492; b=MtTMn6YAgt63PiLZWQZLAYe+1kvKxbYndgDbrEc8qmTLzwmksGIoYCwvfdomqqHf5AdbXPsp MTuP30HpnA8fz0bkHTaQW10KP4JWkQkgyDnf1c28sDVJXm5YsgiCcLO0xFkNIwcm3ecF0xQ+ivM KRYhZEargjCrayG58dkxtj8c= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 48f0776ddb594f90; 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> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit __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