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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D6B8CEB64D9 for ; Wed, 14 Jun 2023 16:07:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230495AbjFNQHr (ORCPT ); Wed, 14 Jun 2023 12:07:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58364 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230195AbjFNQHo (ORCPT ); Wed, 14 Jun 2023 12:07:44 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6E3DD1FCA for ; Wed, 14 Jun 2023 09:07:43 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id F40A660FAA for ; Wed, 14 Jun 2023 16:07:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1C99AC433C8; Wed, 14 Jun 2023 16:07:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1686758862; bh=OV3jfhvD00wR731+Canfp/ZLczj9zpLC9E1ABGGYALA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=id9xKMWZKrqsIjjsKY4sPmy/UUNEAZPrtKia1/TUhVCQqzJGbe6eVODhg28YsDaIk LczjsjYql35+HdM2kcEN/MFBe9B3XcoWawx5ItWpqV0NnD4QjjPQjdWTSdVURwprjV h+X+rkLuR/7AulWfoglXkVSp+vpWdZFN07MWFIZFsF58UYzybiAOAXhszPWcyzcZSi Q8/9LnUiHasvzCGONlOrHrqjEY1/4S5D0pDIT/vfYU/0pv6bhxdDIQZHJl4SvLjeDs vjKe51kRqbI8Keah4xc7xrSfF5YkZ1N332xlrit+vz1exFDdYL74Nqvh3BJJi9xy60 AyeBMIZhLyEQw== Date: Wed, 14 Jun 2023 19:07:10 +0300 From: Mike Rapoport To: Song Shuai Cc: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] memblock: Add error message when memblock_can_resize is not ready Message-ID: <20230614160710.GH52412@kernel.org> References: <20230614131746.3670303-1-songshuaishuai@tinylab.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230614131746.3670303-1-songshuaishuai@tinylab.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Wed, Jun 14, 2023 at 09:17:46PM +0800, Song Shuai wrote: > The memblock APIs are always correct, thus the callers usually don't > handle the return code. But the failure caused by unready memblock_can_resize > is hard to recognize without the return code. Like this piece of log: Please make it clear that failure is in memblock_double_array(), e.g. But when memblock_double_array() is called before memblock_can_resize is true, it is hard to understand the actual reason for the failure. > > ``` > [ 0.000000] memblock_phys_alloc_range: 4096 bytes align=0x1000 from=0x0000000000000000 max_addr=0x0000000000000000 alloc_pmd_fixmap+0x14/0x1c > [ 0.000000] memblock_reserve: [0x000000017ffff000-0x000000017fffffff] memblock_alloc_range_nid+0xb8/0x128 > [ 0.000000] Oops - store (or AMO) access fault [#1] > ``` > > So add an error message for this kind of failure: > > ``` > [ 0.000000] memblock_phys_alloc_range: 4096 bytes align=0x1000 from=0x0000000000000000 max_addr=0x0000000000000000 alloc_pmd_fixmap+0x14/0x1c > [ 0.000000] memblock_reserve: [0x000000017ffff000-0x000000017fffffff] memblock_alloc_range_nid+0xb8/0x128 > [ 0.000000] memblock: Can't double reserved array for area start 0x000000017ffff000 size 4096 > [ 0.000000] Oops - store (or AMO) access fault [#1] > ``` > > Signed-off-by: Song Shuai > --- > mm/memblock.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/mm/memblock.c b/mm/memblock.c > index 3feafea06ab2..ab952a164f62 100644 > --- a/mm/memblock.c > +++ b/mm/memblock.c > @@ -418,8 +418,11 @@ static int __init_memblock memblock_double_array(struct memblock_type *type, > /* We don't allow resizing until we know about the reserved regions > * of memory that aren't suitable for allocation > */ > - if (!memblock_can_resize) > + if (!memblock_can_resize) { > + pr_err("memblock: Can't double %s array for area start %pa size %ld\n", > + type->name, &new_area_start, (unsigned long)new_area_size); Most of the time memblock uses %llu and cast to u64 to print size, please make this consistent. > return -1; > + } > > /* Calculate new doubled size */ > old_size = type->max * sizeof(struct memblock_region); > -- > 2.20.1 > > -- Sincerely yours, Mike.