NUMA_MAPS(5) Linux Programmer's Manual NUMA_MAPS(5)NAMEnuma_maps - information about numa memory
DESCRIPTION
The file /proc/<pid>/numa_maps contrains information about each memory
area used by a given process allowing--among other information--the
determination of which nodes were used for the pages.
numa_maps is only read by programs or by shell commands, and not writ‐
ten to. A read operation on the file will make the kernel scan the
memory area of a process to determine how memory is used. One line is
displayed for each memory area of the process.
The numa_maps format is very simple. The first field shown on each line
is the starting address that allows a correlation with output from
/proc/<pid/maps. The second field shows the memory policy currently in
effect for this particular memory area.
The rest of the line contains series of informationi items about the
pages in the memory area.
Possible information items
N<node>=<pages>
The number of pages used on a node. The number of pages
includes only pages mapped by this process. If this is a
shared mapping then other processes may have mapped dif‐
ferent pages in a memory area. Note also that page
migration may have temporarily unmapped pages. These may
only show up again after the process has attempted to
reference these pages.
file=<filename>
The file backing the memory area. If COW (Copy-On-Write)
pages were generated then the memory area may contain
additional anonymous pages.
heap Memory area is used for the heap.
stack Memory area is used for the stack.
huge Huge memory area. The page counts shown are huge pages
and not regular sized pages.
anon=<pages> The number of anonymous page in the range.
dirty=<pages> Number of dirty pages
mapped=<pages> Number of mapped pages for file backed files. Only shown
if different from the count of anonymous and dirty
pages.
mapmax=<count> Maximum mapcount (number of processes mapping a single
page) encountered during scan. This may be used as an
indicator as to the sharing occuring in a given memory
area.
swapcache=<count>
Number of pages that have an associated entry on the
swap device.
active=<pages> The number of pages on the active list (only shown if
different from the number of pages in this area). If
this item is shown then some inactive pages exist in
that particular memory area that may be removed from
memory by the swapper soon.
writeback=<pages>
Number of pages that are currently being written out to
disk.
FILES
/proc/<pid>/numa_maps
SEE ALSOmigratepages(8), numactl(8), cpuset(8), numactl(5)Linux 2.6 06 March 2006 NUMA_MAPS(5)
