admin-guide/mm/pagemap.rst

37    swap. Unmapped pages return a null PFN. This allows determining
38    precisely which pages are mapped (or in swap) and comparing mapped
39    pages between processes.
44    for pages part of a larger allocation (e.g., THP) can differ: bit 56 is set
45    if all pages part of the corresponding large allocation are *certainly*
117     An order N block has 2^N physically contiguous pages, with the BUDDY flag
120     A compound page with order N consists of 2^N physically contiguous pages.
123     pages are hugeTLB pages (Documentation/admin-guide/mm/hugetlbpage.rst),
125     However in this interface, only huge/giga pages are made visible
136     Identical memory pages dynamically shared between one or more processes.
138     Contiguous pages which construct THP of any size and mapped by any granularity.
175    not a candidate for LRU page reclaims, e.g. ramfs pages,
196 Page table entries for shared pages are cleared when the pages are zapped or
197 swapped out. This makes swapped out pages indistinguishable from never-allocated
207 lseek() can differentiate between accessed pages (present or swapped out) and
209 the pages are backed. For anonymous shared pages, the file can be found in
212 mincore() can differentiate between pages in memory (present, including swap
236 - Write-protect the pages. The ``PM_SCAN_WP_MATCHING`` is used to write-protect
237   the pages of interest. The ``PM_SCAN_CHECK_WPASYNC`` aborts the operation if
238   non-Async Write Protected pages are found. The ``PM_SCAN_WP_MATCHING`` can be
241   get and write protect the pages as well.
243 Following flags about pages are currently supported:
268  6. The optional maximum requested pages are specified in the ``max_pages``.
272 Find pages which have been written and WP them as well::
282 Find pages which have been written, are file backed, not swapped and either
298 the user can find the true soft-dirty pages in case of normal pages. (There may
299 still be extra dirty pages reported for THP or Hugetlb pages.)
313  5. Now the ``PAGEMAP_SCAN`` IOCTL can be used to either just find pages which
315     the pages as well.