From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D1C91CA6019 for ; Fri, 9 Oct 2026 13:32:28 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [127.0.0.1]) by lists.ozlabs.org (Postfix) with ESMTP id 4j1STQ6kGxz3048; Sat, 10 Oct 2026 00:32:26 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; arc=none smtp.remote-ip="2001:41d0:203:375::2a" ARC-Seal: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1791527804; cv=none; b=R1Nxx56RotJGaZnfNm42ej4BeZ4/XgVEulWhhge5PyVSk0qoCLUb5/kFMOjPSlVIdsEupjXP5HC7vrF5ZONG0UxjHf+F02nMWSwKrTlpmYbKJxN+gM0EBNZPJq7tweyQc121IG7M5hfNT9ehnbl11djTYi1ShgYA4E54mVnCWGOVreFfRs47ZgFPTlNU276MVTxsyhSUSLutweQIblxiwD3o5yjloW4rETDeV5EGTlrA0HPXJAEtrPt2+0lugqeC4AVFZbwlL+WUWmA7MzX+ApjxCw0/mvN96SA8c4zj/U6wu7X5f1R1CRTeUsNW+j3OceRo233sPgKLim8p38+QEg== ARC-Message-Signature: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1791527804; c=relaxed/relaxed; bh=Uh2O0hPc7+AfgiciCPNYS5qtLSlalh9WpPtHIZy4QUM=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=kRRqLKxI/ze8zBWYEcggJQiOI0CWR462iPzqwAHr6Kd+UAQrCzZ/OUFzBf0VWvDJLYWxAfmkYLokjqSj8PuA67TJb9wKfq+WVuHMATy23Cb/zSzRhN97FEy0yjdLW5oB9I/XLILcpn/C0aUY1B9c2wJLqsmL2B4kgc8FEvoLgcBstBtu0da5cNqqyQPTopGnMsNOPpog0yQg7NRIHhxpSCbqgfvnkJed8pZqrIZMNWwKbXlwgKyXHRjJ1B5fUOlqzLk6axl51un9apLC6ZMi+2nf9PncA+J24HDl+weW2KQPs2a0293sk+RmKkZGCht2yJnb25QZznGPhvxlvbx/Ig== ARC-Authentication-Results: i=1; lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=linux.dev; dkim=pass (1024-bit key; unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=Tq5jaOpF; dkim-atps=neutral; spf=pass (client-ip=2001:41d0:203:375::2a; helo=mta1.migadu.com; envelope-from=hao.ge@linux.dev; receiver=lists.ozlabs.org) smtp.mailfrom=linux.dev Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=Tq5jaOpF; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=linux.dev (client-ip=2001:41d0:203:375::2a; helo=mta1.migadu.com; envelope-from=hao.ge@linux.dev; receiver=lists.ozlabs.org) X-Greylist: delayed 61 seconds by postgrey-1.37 at boromir; Fri, 09 Oct 2026 17:36:41 AEDT Received: from mta1.migadu.com (out-42.mta1.migadu.com [IPv6:2001:41d0:203:375::2a]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange x25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4j1HFj1wjcz2ynZ for ; Fri, 09 Oct 2026 17:36:40 +1100 (AEDT) X-Envelope-To: linuxppc-dev@lists.ozlabs.org DKIM-Signature: a=rsa-sha256; bh=XX490udm4Ta6ALheN6Xuua3sT0ZXTpdEDmRJNuiAJBs=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1791527782; v=1; x=1792132582; b=Tq5jaOpF3DaN/KjM1sTJ9Kt+qtUR74OOFPzsUK5mu/rJy7iP8nwLZ/U5qbYT1NJrDtUpI0m4 Pr3i264mbDoSlhbZEgkdKDC4I4tpufbBOvXapzekMxm/smgT4vG8u5GvDFPRUlx8gN8+xMFt9tz I0h43YIcNzUzCi+1GNSf+5t4= X-Envelope-To: linuxppc-dev@lists.ozlabs.org Received: by smtp.migadu.com with ESMTPS id a2f462b3a15301f0; Fri, 09 Oct 2026 06:36:22 +0000 X-Mizu-Trace-ID: a2f462b3a15301f0 X-Migadu-Flow: FLOW_OUT From: Hao Ge To: Suren Baghdasaryan , 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 Cc: Hao Ge , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-mm@kvack.org Subject: [RFC PATCH 4/4] mm/percpu: stop unmapping the CPU that failed to map Date: Fri, 9 Oct 2026 14:36:19 +0800 Message-Id: <20261009063619.112313-5-hao.ge@linux.dev> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20261009063619.112313-1-hao.ge@linux.dev> References: <20261009063619.112313-1-hao.ge@linux.dev> X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list 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. 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