From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <55006DC4.2020002@yandex-team.ru> Date: Wed, 11 Mar 2015 19:31:00 +0300 From: Konstantin Khlebnikov MIME-Version: 1.0 Subject: Re: [PATCH 2/4] mm, procfs: account for shmem swap in /proc/pid/smaps References: <1424958666-18241-1-git-send-email-vbabka@suse.cz> <1424958666-18241-3-git-send-email-vbabka@suse.cz> <5500592D.4090309@yandex-team.ru> <55005EBA.8080201@redhat.com> In-Reply-To: <55005EBA.8080201@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-Archive: List-Post: To: Jerome Marchand , Konstantin Khlebnikov , Vlastimil Babka Cc: "linux-mm@kvack.org" , Linux Kernel Mailing List , Andrew Morton , linux-doc@vger.kernel.org, Hugh Dickins , Michal Hocko , "Kirill A. Shutemov" , Cyrill Gorcunov , Randy Dunlap , linux-s390@vger.kernel.org, Martin Schwidefsky , Heiko Carstens , Peter Zijlstra , Paul Mackerras , Arnaldo Carvalho de Melo , Oleg Nesterov List-ID: On 11.03.2015 18:26, Jerome Marchand wrote: > On 03/11/2015 04:03 PM, Konstantin Khlebnikov wrote: >> On 11.03.2015 15:30, Konstantin Khlebnikov wrote: >>> On Thu, Feb 26, 2015 at 4:51 PM, Vlastimil Babka wrote: >>>> Currently, /proc/pid/smaps will always show "Swap: 0 kB" for >>>> shmem-backed >>>> mappings, even if the mapped portion does contain pages that were >>>> swapped out. >>>> This is because unlike private anonymous mappings, shmem does not >>>> change pte >>>> to swap entry, but pte_none when swapping the page out. In the smaps >>>> page >>>> walk, such page thus looks like it was never faulted in. >>> >>> Maybe just add count of swap entries allocated by mapped shmem into >>> swap usage of this vma? That's isn't exactly correct for partially >>> mapped shmem but this is something weird anyway. >> >> Something like that (see patch in attachment) >> > > -8<--- > > diff --git a/mm/shmem.c b/mm/shmem.c > index cf2d0ca010bc..492f78f51fc2 100644 > --- a/mm/shmem.c > +++ b/mm/shmem.c > @@ -1363,6 +1363,13 @@ static struct mempolicy *shmem_get_policy(struct > vm_area_struct *vma, > } > #endif > > +static unsigned long shmem_get_swap_usage(struct vm_area_struct *vma) > +{ > + struct inode *inode = file_inode(vma->vm_file); > + > + return SHMEM_I(inode)->swapped; > +} > + > int shmem_lock(struct file *file, int lock, struct user_struct *user) > { > struct inode *inode = file_inode(file); > > -8<--- > > That will not work for shared anonymous mapping since they all share the > same vm_file (/dev/zero). Nope. They have different files and inodes. They're just called "/dev/zero (deleted)". > > Jerome > -- Konstantin -- 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