From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-f198.google.com (mail-qk0-f198.google.com [209.85.220.198]) by kanga.kvack.org (Postfix) with ESMTP id 9B0206B0253 for ; Thu, 13 Oct 2016 21:02:11 -0400 (EDT) Received: by mail-qk0-f198.google.com with SMTP id f128so61974834qkb.1 for ; Thu, 13 Oct 2016 18:02:11 -0700 (PDT) Received: from sender153-mail.zoho.com (sender153-mail.zoho.com. [74.201.84.153]) by mx.google.com with ESMTPS id d5si8200358qkb.276.2016.10.13.18.02.10 for (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Thu, 13 Oct 2016 18:02:11 -0700 (PDT) Subject: Re: [RFC PATCH 1/1] mm/percpu.c: fix several trivial issues References: <20161014003426.GJ32534@mtj.duckdns.org> From: zijun_hu Message-ID: Date: Fri, 14 Oct 2016 09:01:58 +0800 MIME-Version: 1.0 In-Reply-To: <20161014003426.GJ32534@mtj.duckdns.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Tejun Heo Cc: zijun_hu@htc.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, cl@linux.com On 2016/10/14 8:34, Tejun Heo wrote: > On Tue, Oct 11, 2016 at 09:29:27PM +0800, zijun_hu wrote: >> From: zijun_hu >> >> as shown by pcpu_setup_first_chunk(), the first chunk is same as the >> reserved chunk if the reserved size is nonzero but the dynamic is zero >> this special scenario is referred as the special case by below content >> >> fix several trivial issues: >> >> 1) correct or fix several comments >> the LSB of a chunk->map element is used as free/in-use flag and is cleared >> for free area and set for in-use, rather than use positive/negative number >> to mark area state. >> >> 2) change atomic size to PAGE_SIZE for consistency when CONFIG_SMP == n >> both default setup_per_cpu_areas() and pcpu_page_first_chunk() >> use PAGE_SIZE as atomic size when CONFIG_SMP == y; however >> setup_per_cpu_areas() allocates memory for the only unit with alignment >> PAGE_SIZE but assigns unit size to atomic size when CONFIG_SMP == n, so the >> atomic size isn't consistent with either the alignment or the SMP ones. >> fix it by changing atomic size to PAGE_SIZE when CONFIG_SMP == n >> >> 3) correct empty and populated pages statistic error >> in order to service dynamic atomic memory allocation, the number of empty >> and populated pages of chunks is counted to maintain above a low threshold. >> however, for the special case, the first chunk is took into account by >> pcpu_setup_first_chunk(), it is meaningless since the chunk don't include >> any dynamic areas. >> fix it by excluding the reserved chunk before statistic as the other >> contexts do. >> >> 4) fix potential memory leakage for percpu_init_late() >> in order to manage chunk->map memory uniformly, for the first and reserved >> chunks, percpu_init_late() will allocate memory to replace the static >> chunk->map array within section .init.data after slab is brought up >> however, for the special case, memory are allocated for the same chunk->map >> twice since the first chunk reference is same as the reserved, so the >> memory allocated at the first time are leaked obviously. >> fix it by eliminating the second memory allocation under the special case >> >> Signed-off-by: zijun_hu > > Can you please break the changes into separate patches? > > Thanks. > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org