From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756943AbcLSNQA (ORCPT ); Mon, 19 Dec 2016 08:16:00 -0500 Received: from mail-wj0-f195.google.com ([209.85.210.195]:36468 "EHLO mail-wj0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755416AbcLSNP7 (ORCPT ); Mon, 19 Dec 2016 08:15:59 -0500 Date: Mon, 19 Dec 2016 14:15:56 +0100 From: Michal Hocko To: Vegard Nossum Cc: Andrew Morton , linux-mm@kvack.org, Peter Zijlstra , "Kirill A . Shutemov" , linux-kernel@vger.kernel.org Subject: Re: [PATCH 4/4] mm: clarify mm_struct.mm_{users,count} documentation Message-ID: <20161219131556.GA5164@dhcp22.suse.cz> References: <20161218123229.22952-1-vegard.nossum@oracle.com> <20161218123229.22952-4-vegard.nossum@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161218123229.22952-4-vegard.nossum@oracle.com> User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun 18-12-16 13:32:29, Vegard Nossum wrote: > Clarify documentation relating to mm_users and mm_count, and switch to > kernel-doc syntax. Looks good to me. > Signed-off-by: Vegard Nossum Acked-by: Michal Hocko > --- > include/linux/mm_types.h | 23 +++++++++++++++++++++-- > 1 file changed, 21 insertions(+), 2 deletions(-) > > diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h > index 08d947fc4c59..316c3e1fc226 100644 > --- a/include/linux/mm_types.h > +++ b/include/linux/mm_types.h > @@ -407,8 +407,27 @@ struct mm_struct { > unsigned long task_size; /* size of task vm space */ > unsigned long highest_vm_end; /* highest vma end address */ > pgd_t * pgd; > - atomic_t mm_users; /* How many users with user space? */ > - atomic_t mm_count; /* How many references to "struct mm_struct" (users count as 1) */ > + > + /** > + * @mm_users: The number of users including userspace. > + * > + * Use mmget()/mmget_not_zero()/mmput() to modify. When this drops > + * to 0 (i.e. when the task exits and there are no other temporary > + * reference holders), we also release a reference on @mm_count > + * (which may then free the &struct mm_struct if @mm_count also > + * drops to 0). > + */ > + atomic_t mm_users; > + > + /** > + * @mm_count: The number of references to &struct mm_struct > + * (@mm_users count as 1). > + * > + * Use mmgrab()/mmdrop() to modify. When this drops to 0, the > + * &struct mm_struct is freed. > + */ > + atomic_t mm_count; > + > atomic_long_t nr_ptes; /* PTE page table pages */ > #if CONFIG_PGTABLE_LEVELS > 2 > atomic_long_t nr_pmds; /* PMD page table pages */ > -- > 2.11.0.1.gaa10c3f > -- Michal Hocko SUSE Labs