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authorPaul Burton <paulburton@kernel.org>2019-11-01 14:35:49 -0700
committerPaul Burton <paulburton@kernel.org>2019-11-01 14:36:44 -0700
commit02fce139fd14d3b0126f0a72e8c0a83b5b01f9f5 (patch)
tree20e69aae8d0acfcd7edc954e70a9d751e0b54a7e /Documentation/admin-guide/cgroup-v2.rst
parent8a5a499871308c093ced3c5a383b72502b96e0d2 (diff)
parentb42aa3fd5957e4daf4b69129e5ce752a2a53e7d6 (diff)
downloadlinux-02fce139fd14d3b0126f0a72e8c0a83b5b01f9f5.tar.bz2
Merge tag 'mips_fixes_5.4_3' into mips-next
Pull in mips-fixes primarily to gain build fixes in order to allow better testing of mips-next. A few MIPS fixes: - Fix VDSO time-related function behavior for systems where we need to fall back to syscalls, but were instead returning bogus results. - A fix to TLB exception handlers for Cavium Octeon systems where they would inadvertently clobber the $1/$at register. - A build fix for bcm63xx configurations. - Switch to using my @kernel.org email address. Signed-off-by: Paul Burton <paulburton@kernel.org>
Diffstat (limited to 'Documentation/admin-guide/cgroup-v2.rst')
-rw-r--r--Documentation/admin-guide/cgroup-v2.rst20
1 files changed, 14 insertions, 6 deletions
diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index 0fa8c0e615c2..5361ebec3361 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -615,8 +615,8 @@ on an IO device and is an example of this type.
Protections
-----------
-A cgroup is protected to be allocated upto the configured amount of
-the resource if the usages of all its ancestors are under their
+A cgroup is protected upto the configured amount of the resource
+as long as the usages of all its ancestors are under their
protected levels. Protections can be hard guarantees or best effort
soft boundaries. Protections can also be over-committed in which case
only upto the amount available to the parent is protected among
@@ -1096,7 +1096,10 @@ PAGE_SIZE multiple when read back.
is within its effective min boundary, the cgroup's memory
won't be reclaimed under any conditions. If there is no
unprotected reclaimable memory available, OOM killer
- is invoked.
+ is invoked. Above the effective min boundary (or
+ effective low boundary if it is higher), pages are reclaimed
+ proportionally to the overage, reducing reclaim pressure for
+ smaller overages.
Effective min boundary is limited by memory.min values of
all ancestor cgroups. If there is memory.min overcommitment
@@ -1118,7 +1121,10 @@ PAGE_SIZE multiple when read back.
Best-effort memory protection. If the memory usage of a
cgroup is within its effective low boundary, the cgroup's
memory won't be reclaimed unless memory can be reclaimed
- from unprotected cgroups.
+ from unprotected cgroups. Above the effective low boundary (or
+ effective min boundary if it is higher), pages are reclaimed
+ proportionally to the overage, reducing reclaim pressure for
+ smaller overages.
Effective low boundary is limited by memory.low values of
all ancestor cgroups. If there is memory.low overcommitment
@@ -2482,8 +2488,10 @@ system performance due to overreclaim, to the point where the feature
becomes self-defeating.
The memory.low boundary on the other hand is a top-down allocated
-reserve. A cgroup enjoys reclaim protection when it's within its low,
-which makes delegation of subtrees possible.
+reserve. A cgroup enjoys reclaim protection when it's within its
+effective low, which makes delegation of subtrees possible. It also
+enjoys having reclaim pressure proportional to its overage when
+above its effective low.
The original high boundary, the hard limit, is defined as a strict
limit that can not budge, even if the OOM killer has to be called.