Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757447AbcJNBCU (ORCPT ); Thu, 13 Oct 2016 21:02:20 -0400 Received: from sender153-mail.zoho.com ([74.201.84.153]:25497 "EHLO sender153-mail.zoho.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757430AbcJNBCI (ORCPT ); Thu, 13 Oct 2016 21:02:08 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=zapps768; d=zoho.com; h=subject:to:references:cc:from:message-id:date:user-agent:mime-version:in-reply-to:content-type; b=hG+kNaXnBsj+bnB4MazHkxnpX351kDMc3wIW/3vDqBVbr+k+ECRCVr2kff6Y/ug4ErB5uPvrsunP 5hub6nYU9rzoHl7lQSicaLS5ZS63IrP51ANhmjiMHMujl2bmZrno Subject: Re: [RFC PATCH 1/1] mm/percpu.c: fix several trivial issues To: Tejun Heo References: <20161014003426.GJ32534@mtj.duckdns.org> Cc: zijun_hu@htc.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, cl@linux.com From: zijun_hu Message-ID: Date: Fri, 14 Oct 2016 09:01:58 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <20161014003426.GJ32534@mtj.duckdns.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2289 Lines: 48 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. >