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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2B259C433F5 for ; Sun, 10 Oct 2021 21:36:59 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A8BD2610E5 for ; Sun, 10 Oct 2021 21:36:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org A8BD2610E5 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id E84416B006C; Sun, 10 Oct 2021 17:36:57 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E343B900002; Sun, 10 Oct 2021 17:36:57 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D22AB6B0073; Sun, 10 Oct 2021 17:36:57 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0186.hostedemail.com [216.40.44.186]) by kanga.kvack.org (Postfix) with ESMTP id C0B356B006C for ; Sun, 10 Oct 2021 17:36:57 -0400 (EDT) Received: from smtpin36.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 7B5358249980 for ; Sun, 10 Oct 2021 21:36:57 +0000 (UTC) X-FDA: 78681838074.36.EA394BB Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf04.hostedemail.com (Postfix) with ESMTP id 310DC5001986 for ; Sun, 10 Oct 2021 21:36:57 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id C180D610C7; Sun, 10 Oct 2021 21:36:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1633901813; bh=DufKEuJC7yYgeMY+f5psVRbO7uxiZYwbdvgx7IkVa1k=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=eFQKLwJbGwwvi6WmGCzsxmMLh0rLLHqSoB0GzNw8a3BZdxX82W5yCo6foc1IJwp/6 gypDPsALymtcVqS48Rk6xgwFD61e0kZLwI1D7/Jd4WaRNdEIGmQ1QVZ8haiFVsmxpG Ove7wxLzkj5bDnHgEu2tQ5BUU0jfgA1h5mr4VEuA= Date: Sun, 10 Oct 2021 14:36:22 -0700 From: Andrew Morton To: Kefeng Wang Cc: , , , , , , , , , , Subject: Re: [PATCH v4 0/3] arm64: support page mapping percpu first chunk allocator Message-Id: <20211010143622.18f491df5591d039cda8f7b7@linux-foundation.org> In-Reply-To: <20210910053354.26721-1-wangkefeng.wang@huawei.com> References: <20210910053354.26721-1-wangkefeng.wang@huawei.com> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 310DC5001986 X-Stat-Signature: kj9x3fgiw3y3pr5hxkbofaq64b5m8ee6 Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=eFQKLwJb; dmarc=none; spf=pass (imf04.hostedemail.com: domain of akpm@linux-foundation.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org X-HE-Tag: 1633901817-781311 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, 10 Sep 2021 13:33:51 +0800 Kefeng Wang wrote: > Percpu embedded first chunk allocator is the firstly option, but it > could fails on ARM64, eg, > "percpu: max_distance=0x5fcfdc640000 too large for vmalloc space 0x781fefff0000" > "percpu: max_distance=0x600000540000 too large for vmalloc space 0x7dffb7ff0000" > "percpu: max_distance=0x5fff9adb0000 too large for vmalloc space 0x5dffb7ff0000" > > then we could meet "WARNING: CPU: 15 PID: 461 at vmalloc.c:3087 pcpu_get_vm_areas+0x488/0x838", > even the system could not boot successfully. > > Let's implement page mapping percpu first chunk allocator as a fallback > to the embedding allocator to increase the robustness of the system. > > Also fix a crash when both NEED_PER_CPU_PAGE_FIRST_CHUNK and KASAN_VMALLOC enabled. How serious are these problems in real-world situations? Do people feel that a -stable backport is needed, or is a 5.16-rc1 merge sufficient?