Messages in this thread | | | Date | Wed, 11 Mar 2015 19:31:00 +0300 | From | Konstantin Khlebnikov <> | Subject | Re: [PATCH 2/4] mm, procfs: account for shmem swap in /proc/pid/smaps |
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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 <vbabka@suse.cz> 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
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