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Diffstat (limited to 'Documentation/admin-guide/mm/pagemap.rst')
| -rw-r--r-- | Documentation/admin-guide/mm/pagemap.rst | 25 |
1 files changed, 2 insertions, 23 deletions
diff --git a/Documentation/admin-guide/mm/pagemap.rst b/Documentation/admin-guide/mm/pagemap.rst index f5f065c67615..caba0f52dd36 100644 --- a/Documentation/admin-guide/mm/pagemap.rst +++ b/Documentation/admin-guide/mm/pagemap.rst @@ -118,7 +118,7 @@ Short descriptions to the page flags 21 - KSM Identical memory pages dynamically shared between one or more processes. 22 - THP - Contiguous pages which construct transparent hugepages. + Contiguous pages which construct THP of any size and mapped by any granularity. 23 - OFFLINE The page is logically offline. 24 - ZERO_PAGE @@ -173,27 +173,6 @@ LRU related page flags The page-types tool in the tools/mm directory can be used to query the above flags. -Using pagemap to do something useful -==================================== - -The general procedure for using pagemap to find out about a process' memory -usage goes like this: - - 1. Read ``/proc/pid/maps`` to determine which parts of the memory space are - mapped to what. - 2. Select the maps you are interested in -- all of them, or a particular - library, or the stack or the heap, etc. - 3. Open ``/proc/pid/pagemap`` and seek to the pages you would like to examine. - 4. Read a u64 for each page from pagemap. - 5. Open ``/proc/kpagecount`` and/or ``/proc/kpageflags``. For each PFN you - just read, seek to that entry in the file, and read the data you want. - -For example, to find the "unique set size" (USS), which is the amount of -memory that a process is using that is not shared with any other process, -you can go through every map in the process, find the PFNs, look those up -in kpagecount, and tally up the number of pages that are only referenced -once. - Exceptions for Shared Memory ============================ @@ -252,7 +231,7 @@ Following flags about pages are currently supported: - ``PAGE_IS_PRESENT`` - Page is present in the memory - ``PAGE_IS_SWAPPED`` - Page is in swapped - ``PAGE_IS_PFNZERO`` - Page has zero PFN -- ``PAGE_IS_HUGE`` - Page is THP or Hugetlb backed +- ``PAGE_IS_HUGE`` - Page is PMD-mapped THP or Hugetlb backed - ``PAGE_IS_SOFT_DIRTY`` - Page is soft-dirty The ``struct pm_scan_arg`` is used as the argument of the IOCTL. |