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authorMiquel Raynal <miquel.raynal@bootlin.com>2019-11-17 18:34:01 +0100
committerMiquel Raynal <miquel.raynal@bootlin.com>2019-11-17 18:34:01 +0100
commit8389a7b909f252e74ea92b2794de8d660cfee96e (patch)
treea947f3080e953e4a44417389b3f2b69d4817be2e /Documentation/admin-guide/cgroup-v2.rst
parentMerge CFI/Hyperbus tag 'for-v5.5-rc1' into mtd/next (diff)
parentmtd: spi-nor: Set default Quad Enable method for ISSI flashes (diff)
downloadlinux-8389a7b909f252e74ea92b2794de8d660cfee96e.tar.xz
linux-8389a7b909f252e74ea92b2794de8d660cfee96e.zip
Merge tag 'spi-nor/for-5.5' into mtd/next
SPI NOR core changes: - introduce 'struct spi_nor_controller_ops', - clean the Register Operations methods, - use dev_dbg insted of dev_err for low level info, - fix retlen handling in sst_write(), - fix silent truncations in spi_nor_read and spi_nor_read_raw(), - fix the clearing of QE bit on lock()/unlock(), - rework the disabling of the block write protection, - rework the Quad Enable methods, - make sure nor->spimem and nor->controller_ops are mutually exclusive, - set default Quad Enable method for ISSI flashes, - add support for few flashes. SPI NOR controller drivers changes: - intel-spi: - support chips without software sequencer, - add support for Intel Cannon Lake and Intel Comet Lake-H flashes.
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.