On 03/11/2015 01:30 PM, Konstantin Khlebnikov wrote:
On Thu, Feb 26, 2015 at 4:51 PM, Vlastimil Babka <vbabka@xxxxxxx> 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.
Yeah for next version I want to add a patch optimizing for the
(hopefully) common cases:
1. SHMEM_I(inode)->swapped is 0 - no need to consult radix tree
2. shmem inode is mapped fully (I hope it's ok to just compare its size
and mapping size) - just use the value of SHMEM_I(inode)->swapped like
you suggest
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