Documentation/vm/unevictable-lru.rst

183 page_evictable() also checks for mlocked pages by testing an additional page
224 NOMMU situations, all mappings are effectively mlocked.
230 The "Unevictable mlocked Pages" infrastructure is based on work originally
231 posted by Nick Piggin in an RFC patch entitled "mm: mlocked pages off LRU".
233 to achieve the same objective: hiding mlocked pages from vmscan.
237 prevented the management of the pages on an LRU list, and thus mlocked pages
241 Nick resolved this by putting mlocked pages back on the lru list before
251 mlocked pages - pages mapped into a VM_LOCKED VMA - are a class of unevictable
267  (4) in the fault path, if mlocked pages are "culled" in the fault path,
276 mlocked pages become unlocked and rescued from the unevictable list when:
304 mark the pages as mlocked via mlock_vma_page().
306 Note that the VMA being mlocked might be mapped with PROT_NONE.  In this case,
322 be mlocked by another task/VMA and we don't want to do extra work.  We
323 especially do not want to count an mlocked page more than once in the
324 statistics.  If the page was already mlocked, mlock_vma_page() need do nothing
327 If the page was NOT already mlocked, mlock_vma_page() attempts to isolate the
331 is now mlocked and divert the page to the zone's unevictable list.  If
343    mlocked.  In any case, most of the pages have no struct page in which to so
384 these pages for munlocking.  Because we don't want to leave pages mlocked,
394 mlocked, munlock_vma_page() updates that zone statistics for the number of
395 mlocked pages.  Note, however, that at this point we haven't checked whether
406 page statistics if it finds another VMA holding the page mlocked.  If we fail
407 to isolate the page, we'll have left a potentially mlocked page on the LRU.
419 of mlocked pages and other unevictable pages.  This involves simply moving the
473 that a region of memory be mlocked supplying the MAP_LOCKED flag to the mmap()
482 in the newly mapped memory being mlocked.  Before the unevictable/mlock
491 to be mlocked to the task's "locked_vm".  To account for filtered VMAs,
492 populate_vma_page_range() returns the number of pages NOT mlocked.  All of the
503 When unmapping an mlocked region of memory, whether by an explicit call to
514 actually contain mlocked pages will be passed to munlock_vma_pages_all().
579 large region or tearing down a large address space that has been mlocked via
602  (3) mlocked pages that could not be isolated from the LRU and moved to the