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authorLinus Torvalds <torvalds@linux-foundation.org>2015-02-12 05:23:28 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2015-02-12 05:23:28 +0300
commit59d53737a8640482995fea13c6e2c0fd016115d6 (patch)
tree3423eb92315865d76cb8d488513bfef6ab9251d0 /Documentation/filesystems
parentd3f180ea1a44aecba1b0dab2a253428e77f906bf (diff)
parent8138a67a5557ffea3a21dfd6f037842d4e748513 (diff)
downloadlinux-59d53737a8640482995fea13c6e2c0fd016115d6.tar.xz
Merge branch 'akpm' (patches from Andrew)
Merge second set of updates from Andrew Morton: "More of MM" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (83 commits) mm/nommu.c: fix arithmetic overflow in __vm_enough_memory() mm/mmap.c: fix arithmetic overflow in __vm_enough_memory() vmstat: Reduce time interval to stat update on idle cpu mm/page_owner.c: remove unnecessary stack_trace field Documentation/filesystems/proc.txt: describe /proc/<pid>/map_files mm: incorporate read-only pages into transparent huge pages vmstat: do not use deferrable delayed work for vmstat_update mm: more aggressive page stealing for UNMOVABLE allocations mm: always steal split buddies in fallback allocations mm: when stealing freepages, also take pages created by splitting buddy page mincore: apply page table walker on do_mincore() mm: /proc/pid/clear_refs: avoid split_huge_page() mm: pagewalk: fix misbehavior of walk_page_range for vma(VM_PFNMAP) mempolicy: apply page table walker on queue_pages_range() arch/powerpc/mm/subpage-prot.c: use walk->vma and walk_page_vma() memcg: cleanup preparation for page table walk numa_maps: remove numa_maps->vma numa_maps: fix typo in gather_hugetbl_stats pagemap: use walk->vma instead of calling find_vma() clear_refs: remove clear_refs_private->vma and introduce clear_refs_test_walk() ...
Diffstat (limited to 'Documentation/filesystems')
-rw-r--r--Documentation/filesystems/proc.txt23
1 files changed, 23 insertions, 0 deletions
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index 79b3cc821e7b..cf8fc2f0b34b 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -42,6 +42,7 @@ Table of Contents
3.6 /proc/<pid>/comm & /proc/<pid>/task/<tid>/comm
3.7 /proc/<pid>/task/<tid>/children - Information about task children
3.8 /proc/<pid>/fdinfo/<fd> - Information about opened file
+ 3.9 /proc/<pid>/map_files - Information about memory mapped files
4 Configuring procfs
4.1 Mount options
@@ -1763,6 +1764,28 @@ pair provide additional information particular to the objects they represent.
with TIMER_ABSTIME option which will be shown in 'settime flags', but 'it_value'
still exhibits timer's remaining time.
+3.9 /proc/<pid>/map_files - Information about memory mapped files
+---------------------------------------------------------------------
+This directory contains symbolic links which represent memory mapped files
+the process is maintaining. Example output:
+
+ | lr-------- 1 root root 64 Jan 27 11:24 333c600000-333c620000 -> /usr/lib64/ld-2.18.so
+ | lr-------- 1 root root 64 Jan 27 11:24 333c81f000-333c820000 -> /usr/lib64/ld-2.18.so
+ | lr-------- 1 root root 64 Jan 27 11:24 333c820000-333c821000 -> /usr/lib64/ld-2.18.so
+ | ...
+ | lr-------- 1 root root 64 Jan 27 11:24 35d0421000-35d0422000 -> /usr/lib64/libselinux.so.1
+ | lr-------- 1 root root 64 Jan 27 11:24 400000-41a000 -> /usr/bin/ls
+
+The name of a link represents the virtual memory bounds of a mapping, i.e.
+vm_area_struct::vm_start-vm_area_struct::vm_end.
+
+The main purpose of the map_files is to retrieve a set of memory mapped
+files in a fast way instead of parsing /proc/<pid>/maps or
+/proc/<pid>/smaps, both of which contain many more records. At the same
+time one can open(2) mappings from the listings of two processes and
+comparing their inode numbers to figure out which anonymous memory areas
+are actually shared.
+
------------------------------------------------------------------------------
Configuring procfs
------------------------------------------------------------------------------