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-rw-r--r--Documentation/filesystems/proc.txt23
-rw-r--r--Documentation/filesystems/tmpfs.txt8
2 files changed, 23 insertions, 8 deletions
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index 402ab99e409f..e95aa1c6eadf 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -169,6 +169,9 @@ read the file /proc/PID/status:
VmLck: 0 kB
VmHWM: 476 kB
VmRSS: 476 kB
+ RssAnon: 352 kB
+ RssFile: 120 kB
+ RssShmem: 4 kB
VmData: 156 kB
VmStk: 88 kB
VmExe: 68 kB
@@ -231,14 +234,20 @@ Table 1-2: Contents of the status files (as of 4.1)
VmSize total program size
VmLck locked memory size
VmHWM peak resident set size ("high water mark")
- VmRSS size of memory portions
+ VmRSS size of memory portions. It contains the three
+ following parts (VmRSS = RssAnon + RssFile + RssShmem)
+ RssAnon size of resident anonymous memory
+ RssFile size of resident file mappings
+ RssShmem size of resident shmem memory (includes SysV shm,
+ mapping of tmpfs and shared anonymous mappings)
VmData size of data, stack, and text segments
VmStk size of data, stack, and text segments
VmExe size of text segment
VmLib size of shared library code
VmPTE size of page table entries
VmPMD size of second level page tables
- VmSwap size of swap usage (the number of referred swapents)
+ VmSwap amount of swap used by anonymous private data
+ (shmem swap usage is not included)
HugetlbPages size of hugetlb memory portions
Threads number of threads
SigQ number of signals queued/max. number for queue
@@ -265,7 +274,8 @@ Table 1-3: Contents of the statm files (as of 2.6.8-rc3)
Field Content
size total program size (pages) (same as VmSize in status)
resident size of memory portions (pages) (same as VmRSS in status)
- shared number of pages that are shared (i.e. backed by a file)
+ shared number of pages that are shared (i.e. backed by a file, same
+ as RssFile+RssShmem in status)
trs number of pages that are 'code' (not including libs; broken,
includes data segment)
lrs number of pages of library (always 0 on 2.6)
@@ -459,7 +469,10 @@ and a page is modified, the file page is replaced by a private anonymous copy.
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.
"Swap" shows how much would-be-anonymous memory is also used, but out on swap.
-"SwapPss" shows proportional swap share of this mapping.
+For shmem mappings, "Swap" includes also the size of the mapped (and not
+replaced by copy-on-write) part of the underlying shmem object out on swap.
+"SwapPss" shows proportional swap share of this mapping. Unlike "Swap", this
+does not take into account swapped out page of underlying shmem objects.
"Locked" indicates whether the mapping is locked in memory or not.
"VmFlags" field deserves a separate description. This member represents the kernel
@@ -842,6 +855,7 @@ Dirty: 968 kB
Writeback: 0 kB
AnonPages: 861800 kB
Mapped: 280372 kB
+Shmem: 644 kB
Slab: 284364 kB
SReclaimable: 159856 kB
SUnreclaim: 124508 kB
@@ -898,6 +912,7 @@ MemAvailable: An estimate of how much memory is available for starting new
AnonPages: Non-file backed pages mapped into userspace page tables
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
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
diff --git a/Documentation/filesystems/tmpfs.txt b/Documentation/filesystems/tmpfs.txt
index 98ef55124158..d392e1505f17 100644
--- a/Documentation/filesystems/tmpfs.txt
+++ b/Documentation/filesystems/tmpfs.txt
@@ -17,10 +17,10 @@ RAM, where you have to create an ordinary filesystem on top. Ramdisks
cannot swap and you do not have the possibility to resize them.
Since tmpfs lives completely in the page cache and on swap, all tmpfs
-pages currently in memory will show up as cached. It will not show up
-as shared or something like that. Further on you can check the actual
-RAM+swap use of a tmpfs instance with df(1) and du(1).
-
+pages will be shown as "Shmem" in /proc/meminfo and "Shared" in
+free(1). Notice that these counters also include shared memory
+(shmem, see ipcs(1)). The most reliable way to get the count is
+using df(1) and du(1).
tmpfs has the following uses: