There are several shortcomings with the accounting of shared memory (sysV shm, shared anonymous mapping, mapping to a tmpfs file). The values in /proc/<pid>/status and statm don't allow to distinguish between shmem memory and a shared mapping to a regular file, even though theirs implication on memory usage are quite different: at reclaim, file mapping can be dropped or write back on disk while shmem needs a place in swap. As for shmem pages that are swapped-out or in swap cache, they aren't accounted at all. This series addresses these issues by adding new fields to status and smaps file in /proc/<pid>/. The accounting of resident shared memory is made in the same way as it's currently done for resident memory and general swap (a counter in mm_rss_stat), but this approach proved impractical for paged-out shared memory (it would requires a rmap walk each time a page is paged-in). /proc/<pid>/smaps also lacks proper accounting of shared memory since shmem subsystem hides all implementation detail to generic mm code. This series adds the shmem_locate() function that returns the location of a particular page (resident, in swap or swap cache). Called from smaps code, it allows to show more detailled accounting of shmem mappings in smaps. Patch 1 adds a counter to keep track of resident shmem memory. Patch 2 adds a function to allow generic code to know the physical location of a shmem page. Patch 3 adds simple helper function. Patch 4 accounts swapped-out shmem in /proc/<pid>/status. Patch 5 adds shmem specific fields to /proc/<pid>/smaps. Thanks, Jerome Jerome Marchand (5): mm, shmem: Add shmem resident memory accounting mm, shmem: Add shmem_locate function mm, shmem: Add shmem_vma() helper mm, shmem: Add shmem swap memory accounting mm, shmem: Show location of non-resident shmem pages in smaps Documentation/filesystems/proc.txt | 15 ++++ arch/s390/mm/pgtable.c | 2 +- fs/proc/task_mmu.c | 139 +++++++++++++++++++++++++++++++++++-- include/linux/mm.h | 20 ++++++ include/linux/mm_types.h | 7 +- kernel/events/uprobes.c | 2 +- mm/filemap_xip.c | 2 +- mm/memory.c | 37 ++++++++-- mm/rmap.c | 8 +-- mm/shmem.c | 37 ++++++++++ 10 files changed, 249 insertions(+), 20 deletions(-) -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
