- Fix document title to match ReST format
- Convert the table to be properly recognized
- Some indentation fixes to match ReST syntax.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx>
---
.../{halt-polling.txt => halt-polling.rst} | 86 ++++++++++---------
Documentation/virt/kvm/index.rst | 1 +
2 files changed, 46 insertions(+), 41 deletions(-)
rename Documentation/virt/kvm/{halt-polling.txt => halt-polling.rst} (64%)
diff --git a/Documentation/virt/kvm/halt-polling.txt b/Documentation/virt/kvm/halt-polling.rst
similarity index 64%
rename from Documentation/virt/kvm/halt-polling.txt
rename to Documentation/virt/kvm/halt-polling.rst
index 4f791b128dd2..4922e4a15f18 100644
--- a/Documentation/virt/kvm/halt-polling.txt
+++ b/Documentation/virt/kvm/halt-polling.rst
@@ -1,3 +1,6 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+===========================
The KVM halt polling system
===========================
@@ -68,7 +71,8 @@ steady state polling interval but will only really do a good job for wakeups
which come at an approximately constant rate, otherwise there will be constant
adjustment of the polling interval.
-[0] total block time: the time between when the halt polling function is
+[0] total block time:
+ the time between when the halt polling function is
invoked and a wakeup source received (irrespective of
whether the scheduler is invoked within that function).
@@ -81,31 +85,32 @@ shrunk. These variables are defined in include/linux/kvm_host.h and as module
parameters in virt/kvm/kvm_main.c, or arch/powerpc/kvm/book3s_hv.c in the
powerpc kvm-hv case.
-Module Parameter | Description | Default Value
---------------------------------------------------------------------------------
-halt_poll_ns | The global max polling | KVM_HALT_POLL_NS_DEFAULT
- | interval which defines |
- | the ceiling value of the |
- | polling interval for | (per arch value)
- | each vcpu. |
---------------------------------------------------------------------------------
-halt_poll_ns_grow | The value by which the | 2
- | halt polling interval is |
- | multiplied in the |
- | grow_halt_poll_ns() |
- | function. |
---------------------------------------------------------------------------------
-halt_poll_ns_grow_start | The initial value to grow | 10000
- | to from zero in the |
- | grow_halt_poll_ns() |
- | function. |
---------------------------------------------------------------------------------
-halt_poll_ns_shrink | The value by which the | 0
- | halt polling interval is |
- | divided in the |
- | shrink_halt_poll_ns() |
- | function. |
---------------------------------------------------------------------------------
++-----------------------+---------------------------+-------------------------+
+|Module Parameter | Description | Default Value |
++-----------------------+---------------------------+-------------------------+
+|halt_poll_ns | The global max polling | KVM_HALT_POLL_NS_DEFAULT|
+| | interval which defines | |
+| | the ceiling value of the | |
+| | polling interval for | (per arch value) |
+| | each vcpu. | |
++-----------------------+---------------------------+-------------------------+
+|halt_poll_ns_grow | The value by which the | 2 |
+| | halt polling interval is | |
+| | multiplied in the | |
+| | grow_halt_poll_ns() | |
+| | function. | |
++-----------------------+---------------------------+-------------------------+
+|halt_poll_ns_grow_start| The initial value to grow | 10000 |
+| | to from zero in the | |
+| | grow_halt_poll_ns() | |
+| | function. | |
++-----------------------+---------------------------+-------------------------+
+|halt_poll_ns_shrink | The value by which the | 0 |
+| | halt polling interval is | |
+| | divided in the | |
+| | shrink_halt_poll_ns() | |
+| | function. | |
++-----------------------+---------------------------+-------------------------+
These module parameters can be set from the debugfs files in:
@@ -117,20 +122,19 @@ Note: that these module parameters are system wide values and are not able to
Further Notes
=============
-- Care should be taken when setting the halt_poll_ns module parameter as a
-large value has the potential to drive the cpu usage to 100% on a machine which
-would be almost entirely idle otherwise. This is because even if a guest has
-wakeups during which very little work is done and which are quite far apart, if
-the period is shorter than the global max polling interval (halt_poll_ns) then
-the host will always poll for the entire block time and thus cpu utilisation
-will go to 100%.
+- Care should be taken when setting the halt_poll_ns module parameter as a large value
+ has the potential to drive the cpu usage to 100% on a machine which would be almost
+ entirely idle otherwise. This is because even if a guest has wakeups during which very
+ little work is done and which are quite far apart, if the period is shorter than the
+ global max polling interval (halt_poll_ns) then the host will always poll for the
+ entire block time and thus cpu utilisation will go to 100%.
-- Halt polling essentially presents a trade off between power usage and latency
-and the module parameters should be used to tune the affinity for this. Idle
-cpu time is essentially converted to host kernel time with the aim of decreasing
-latency when entering the guest.
+- Halt polling essentially presents a trade off between power usage and latency and
+ the module parameters should be used to tune the affinity for this. Idle cpu time is
+ essentially converted to host kernel time with the aim of decreasing latency when
+ entering the guest.
-- Halt polling will only be conducted by the host when no other tasks are
-runnable on that cpu, otherwise the polling will cease immediately and
-schedule will be invoked to allow that other task to run. Thus this doesn't
-allow a guest to denial of service the cpu.
+- Halt polling will only be conducted by the host when no other tasks are runnable on
+ that cpu, otherwise the polling will cease immediately and schedule will be invoked to
+ allow that other task to run. Thus this doesn't allow a guest to denial of service the
+ cpu.
diff --git a/Documentation/virt/kvm/index.rst b/Documentation/virt/kvm/index.rst
index 488c6370a447..b39f4894b61d 100644
--- a/Documentation/virt/kvm/index.rst
+++ b/Documentation/virt/kvm/index.rst
@@ -9,6 +9,7 @@ KVM
amd-memory-encryption
cpuid
+ halt-polling
vcpu-requests
arm/index
--
2.24.1
