On Fri, Apr 04, 2025 at 04:06:57PM +0200, Pankaj Raghav (Samsung) wrote: > diff --git a/Documentation/admin-guide/mm/transhuge.rst b/Documentation/admin-guide/mm/transhuge.rst > index dff8d5985f0f..f8aae64e38d0 100644 > --- a/Documentation/admin-guide/mm/transhuge.rst > +++ b/Documentation/admin-guide/mm/transhuge.rst > @@ -12,8 +12,8 @@ using huge pages for the backing of virtual memory with huge pages > that supports the automatic promotion and demotion of page sizes and > without the shortcomings of hugetlbfs. > > -Currently THP only works for anonymous memory mappings and tmpfs/shmem. > -But in the future it can expand to other filesystems. > +Currently, THP only works for anonymous memory mappings, tmpfs/shmem and > +filesystems that support large folios. > > .. note:: > in the examples below we presume that the basic page size is 4K and > @@ -463,11 +463,19 @@ fields for each mapping. (Note that AnonHugePages only applies to traditional > PMD-sized THP for historical reasons and should have been called > AnonHugePmdMapped). > > -The number of file transparent huge pages mapped to userspace is available > -by reading ShmemPmdMapped and ShmemHugePages fields in ``/proc/meminfo``. > -To identify what applications are mapping file transparent huge pages, it > -is necessary to read ``/proc/PID/smaps`` and count the FilePmdMapped fields > -for each mapping. > +The number of PMD-sized transparent huge pages currently used by > +filesystem data (page cache) is available by reading the FileHugePages field > +in ``/proc/meminfo``. The number of these huge pages that are mapped to userspace > +is available by reading FilePmdMapped field in ``proc/meminfo``. To identify > +what applications are mapping these huge pages, it is necessary to read > +``/proc/PID/smaps`` and count the FilePmdMapped fields for each mapping. > + > +In similar fashion, the number of PMD-sized transparent huge pages currently > +used by tmpfs/shmem is available by reading the ShmemHugePages field > +in ``/proc/meminfo``. The number of these huge pages that are mapped to userspace > +is available by reading ShmemPmdMapped field in ``proc/meminfo``. To identify > +what applications are mapping these huge pages, it is necessary to read > +``/proc/PID/smaps`` and count the ShmemPmdMapped fields for each mapping. > > Note that reading the smaps file is expensive and reading it > frequently will incur overhead. > Looks good, thanks! Reviewed-by: Bagas Sanjaya <bagasdotme@xxxxxxxxx> -- An old man doll... just what I always wanted! - Clara
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