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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-19 10:09:22 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-19 10:09:22 -0700 |
| commit | f4cdf7ca9a1fdcca413157df19753f388a5a224e (patch) | |
| tree | 60a31895b2446cd7fa27514e8c2843534a0de0da /Documentation/admin-guide/numastat.rst | |
| download | linux-stable-f4cdf7ca9a1fdcca413157df19753f388a5a224e.tar.gz linux-stable-f4cdf7ca9a1fdcca413157df19753f388a5a224e.zip | |
Merge tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-mediagrafted
Pull media updates from Mauro Carvalho Chehab:
- v4l2-core: added ISP statistics support and per-block validation
- v4l2-core: Allow unknown HDR10 white point and luminance
- New camera sensors: Sony IMX678 and IMX471m, Himax HM1092 IR sensor
- New codec: Milos: VPU v2.0 codec support
- isp driver: gained support for Dreamchip RPPX1 ISP framework
- vsp1 driver: gained support for RZ/T2H and RZ/N2H
- Novalake driver: gained CVS support for new NVL hardware
- dvb-core: fix feed leak on failed DMX_ADD_PID
- several driver fixes, cleanups and minor improvements
* tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (308 commits)
media: ipu-bridge: check all DMI entries when overriding sensor rotation
media: v4l2-async: avoid deleting unlinked ASC entry on link error
media: rzg2l-cru: Align bytesperline to hardware DMA stride requirement
media: intel/ipu6: fix async notifier cleanup leak on parse error
media: staging/ipu7: fix async notifier UAF on probe error path
media: amd: isp4: fix self-deadlock in isp4sd_pwron_and_init() error path
media: amd: isp4: release partial allocations in isp4if_alloc_fw_gpumem()
media: rcar-isp: Fix VSPX reference leaks
media: rcar-isp: Release ISPCORE resources
media: i2c: imx415: Release runtime PM reference on VBLANK error
media: i2c: imx415: Return test pattern write errors
media: renesas: vsp1: Declare index variables in for loop statement
media: renesas: vsp1: Make reset control optional to support platforms without a reset line
media: dt-bindings: media: renesas,vsp1: Document RZ/T2H and RZ/N2H SoCs
media: dt-bindings: media: renesas,fcp: Document RZ/T2H and RZ/N2H SoCs
media: nxp: imx8-isi: Add additional 32-bit RGB format support
media: nxp: imx8-isi: Add 16-bit raw Bayer format support
media: nxp: imx8-isi: Implement per-stream reference counting for multiplexed streams
media: nxp: imx8-isi: Use BIT_ULL() for 64-bit stream masks
media: nxp: imx8-isi: Correct color map between V4L2 and ISI
...
Diffstat (limited to 'Documentation/admin-guide/numastat.rst')
| -rw-r--r-- | Documentation/admin-guide/numastat.rst | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/Documentation/admin-guide/numastat.rst b/Documentation/admin-guide/numastat.rst new file mode 100644 index 000000000..08ec2c2bd --- /dev/null +++ b/Documentation/admin-guide/numastat.rst @@ -0,0 +1,55 @@ +=============================== +Numa policy hit/miss statistics +=============================== + +/sys/devices/system/node/node*/numastat + +All units are pages. Hugepages have separate counters. + +The numa_hit, numa_miss and numa_foreign counters reflect how well processes +are able to allocate memory from nodes they prefer. If they succeed, numa_hit +is incremented on the preferred node, otherwise numa_foreign is incremented on +the preferred node and numa_miss on the node where allocation succeeded. + +Usually preferred node is the one local to the CPU where the process executes, +but restrictions such as mempolicies can change that, so there are also two +counters based on CPU local node. local_node is similar to numa_hit and is +incremented on allocation from a node by CPU on the same node. other_node is +similar to numa_miss and is incremented on the node where allocation succeeds +from a CPU from a different node. Note there is no counter analogical to +numa_foreign. + +In more detail: + +=============== ============================================================ +numa_hit A process wanted to allocate memory from this node, + and succeeded. + +numa_miss A process wanted to allocate memory from another node, + but ended up with memory from this node. + +numa_foreign A process wanted to allocate on this node, + but ended up with memory from another node. + +local_node A process ran on this node's CPU, + and got memory from this node. + +other_node A process ran on a different node's CPU + and got memory from this node. + +interleave_hit Interleaving wanted to allocate from this node + and succeeded. +=============== ============================================================ + +For easier reading you can use the numastat utility from the numactl package +(http://oss.sgi.com/projects/libnuma/). Note that it only works +well right now on machines with a small number of CPUs. + +Note that on systems with memoryless nodes (where a node has CPUs but no +memory) the numa_hit, numa_miss and numa_foreign statistics can be skewed +heavily. In the current kernel implementation, if a process prefers a +memoryless node (i.e. because it is running on one of its local CPU), the +implementation actually treats one of the nearest nodes with memory as the +preferred node. As a result, such allocation will not increase the numa_foreign +counter on the memoryless node, and will skew the numa_hit, numa_miss and +numa_foreign statistics of the nearest node. |
