From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f70.google.com (mail-pa0-f70.google.com [209.85.220.70]) by kanga.kvack.org (Postfix) with ESMTP id 01B976B0253 for ; Thu, 13 Oct 2016 20:34:30 -0400 (EDT) Received: by mail-pa0-f70.google.com with SMTP id fn2so97096903pad.7 for ; Thu, 13 Oct 2016 17:34:29 -0700 (PDT) Received: from mail-pf0-x241.google.com (mail-pf0-x241.google.com. [2607:f8b0:400e:c00::241]) by mx.google.com with ESMTPS id v143si12940747pgb.176.2016.10.13.17.34.29 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 13 Oct 2016 17:34:29 -0700 (PDT) Received: by mail-pf0-x241.google.com with SMTP id s8so6014149pfj.2 for ; Thu, 13 Oct 2016 17:34:29 -0700 (PDT) Date: Thu, 13 Oct 2016 20:34:26 -0400 From: Tejun Heo Subject: Re: [RFC PATCH 1/1] mm/percpu.c: fix several trivial issues Message-ID: <20161014003426.GJ32534@mtj.duckdns.org> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: zijun_hu Cc: akpm@linux-foundation.org, zijun_hu@htc.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, cl@linux.com 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. -- tejun -- 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