Merge tag 'tegra-for-4.8-i2c' of git://git.kernel.org/pub/scm/linux/kernel/git/tegra...

[cascardo/linux.git] / Documentation / filesystems / proc.txt

diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index 5b61eea..219ffd4 100644 (file)
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -145,7 +145,7 @@ Table 1-1: Process specific entries in /proc
                symbol the task is blocked in - or "0" if not blocked.
  pagemap       Page table
  stack         Report full stack trace, enable via CONFIG_STACKTRACE
- smaps         a extension based on maps, showing the memory consumption of
+ smaps         an extension based on maps, showing the memory consumption of
                each mapping and flags associated with it
  numa_maps     an extension based on maps, showing the memory locality and
                binding policy as well as mem usage (in pages) of each mapping.
@@ -436,6 +436,7 @@ Private_Dirty:         0 kB
 Referenced:          892 kB
 Anonymous:             0 kB
 AnonHugePages:         0 kB
+ShmemPmdMapped:        0 kB
 Shared_Hugetlb:        0 kB
 Private_Hugetlb:       0 kB
 Swap:                  0 kB
@@ -464,6 +465,8 @@ accessed.
 a mapping associated with a file may contain anonymous pages: when MAP_PRIVATE
 and a page is modified, the file page is replaced by a private anonymous copy.
 "AnonHugePages" shows the ammount of memory backed by transparent hugepage.
+"ShmemPmdMapped" shows the ammount of shared (shmem/tmpfs) memory backed by
+huge pages.
 "Shared_Hugetlb" and "Private_Hugetlb" show the ammounts of memory backed by
 hugetlbfs page which is *not* counted in "RSS" or "PSS" field for historical
 reasons. And these are not included in {Shared,Private}_{Clean,Dirty} field.
@@ -512,6 +515,18 @@ be vanished or the reverse -- new added.
 This file is only present if the CONFIG_MMU kernel configuration option is
 enabled.
 
+Note: reading /proc/PID/maps or /proc/PID/smaps is inherently racy (consistent
+output can be achieved only in the single read call).
+This typically manifests when doing partial reads of these files while the
+memory map is being modified.  Despite the races, we do provide the following
+guarantees:
+
+1) The mapped addresses never go backwards, which implies no two
+   regions will ever overlap.
+2) If there is something at a given vaddr during the entirety of the
+   life of the smaps/maps walk, there will be some output for it.
+
+
 The /proc/PID/clear_refs is used to reset the PG_Referenced and ACCESSED/YOUNG
 bits on both physical and virtual pages associated with a process, and the
 soft-dirty bit on pte (see Documentation/vm/soft-dirty.txt for details).
@@ -868,6 +883,9 @@ VmallocTotal:   112216 kB
 VmallocUsed:       428 kB
 VmallocChunk:   111088 kB
 AnonHugePages:   49152 kB
+ShmemHugePages:      0 kB
+ShmemPmdMapped:      0 kB
+
 
     MemTotal: Total usable ram (i.e. physical ram minus a few reserved
               bits and the kernel binary code)
@@ -912,6 +930,9 @@ MemAvailable: An estimate of how much memory is available for starting new
 AnonHugePages: Non-file backed huge pages mapped into userspace page tables
       Mapped: files which have been mmaped, such as libraries
        Shmem: Total memory used by shared memory (shmem) and tmpfs
+ShmemHugePages: Memory used by shared memory (shmem) and tmpfs allocated
+              with huge pages
+ShmemPmdMapped: Shared memory mapped into userspace with huge pages
         Slab: in-kernel data structures cache
 SReclaimable: Part of Slab, that might be reclaimed, such as caches
   SUnreclaim: Part of Slab, that cannot be reclaimed on memory pressure