SwapPss: 0 kB
KernelPageSize: 4 kB
MMUPageSize: 4 kB
-Locked: 374 kB
-VmFlags: rd ex mr mw me de
+Locked: 0 kB
+VmFlags: rd ex mr mw me dw
the first of these lines shows the same information as is displayed for the
mapping in /proc/PID/maps. The remaining lines show the size of the mapping
"Anonymous" shows the amount of memory that does not belong to any file. Even
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.
-"Swap" shows how much would-be-anonymous memory is also used, but out on
-swap.
-"SwapPss" shows proportional swap share of this mapping.
"AnonHugePages" shows the ammount of memory backed by transparent hugepage.
"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.
+"Swap" shows how much would-be-anonymous memory is also used, but out on swap.
+"SwapPss" shows proportional swap share of this mapping.
+"Locked" indicates whether the mapping is locked in memory or not.
"VmFlags" field deserves a separate description. This member represents the kernel
flags associated with the particular virtual memory area in two letter encoded
ac - area is accountable
nr - swap space is not reserved for the area
ht - area uses huge tlb pages
- nl - non-linear mapping
ar - architecture specific flag
dd - do not include area into core dump
sd - soft-dirty flag
> cat /proc/meminfo
-The "Locked" indicates whether the mapping is locked in memory or not.
-
-
MemTotal: 16344972 kB
MemFree: 13634064 kB
MemAvailable: 14836172 kB
---------------------------------------------------------------
When a process is dumped, all anonymous memory is written to a core file as
long as the size of the core file isn't limited. But sometimes we don't want
-to dump some memory segments, for example, huge shared memory. Conversely,
-sometimes we want to save file-backed memory segments into a core file, not
-only the individual files.
+to dump some memory segments, for example, huge shared memory or DAX.
+Conversely, sometimes we want to save file-backed memory segments into a core
+file, not only the individual files.
/proc/<pid>/coredump_filter allows you to customize which memory segments
will be dumped when the <pid> process is dumped. coredump_filter is a bitmask
of memory types. If a bit of the bitmask is set, memory segments of the
corresponding memory type are dumped, otherwise they are not dumped.
-The following 7 memory types are supported:
+The following 9 memory types are supported:
- (bit 0) anonymous private memory
- (bit 1) anonymous shared memory
- (bit 2) file-backed private memory
effective only if the bit 2 is cleared)
- (bit 5) hugetlb private memory
- (bit 6) hugetlb shared memory
+ - (bit 7) DAX private memory
+ - (bit 8) DAX shared memory
Note that MMIO pages such as frame buffer are never dumped and vDSO pages
are always dumped regardless of the bitmask status.
- Note bit 0-4 doesn't effect any hugetlb memory. hugetlb memory are only
- effected by bit 5-6.
+ Note that bits 0-4 don't affect hugetlb or DAX memory. hugetlb memory is
+ only affected by bit 5-6, and DAX is only affected by bits 7-8.
-Default value of coredump_filter is 0x23; this means all anonymous memory
-segments and hugetlb private memory are dumped.
+The default value of coredump_filter is 0x33; this means all anonymous memory
+segments, ELF header pages and hugetlb private memory are dumped.
If you don't want to dump all shared memory segments attached to pid 1234,
-write 0x21 to the process's proc file.
+write 0x31 to the process's proc file.
- $ echo 0x21 > /proc/1234/coredump_filter
+ $ echo 0x31 > /proc/1234/coredump_filter
When a new process is created, the process inherits the bitmask status from its
parent. It is useful to set up coredump_filter before the program runs.
projects / firefly-linux-kernel-4.4.55.git / blobdiff