Docs/damon: Update documents for better consistency
Subsystems (4)
SeongJae Park
maintainercover Docs/damon: Update documents for better consistency
Some of DAMON document are not properly updated for latest version. This patchset updates such parts.
SeongJae Park (3):
Docs/vm/damon: Call low level monitoring primitives the operations Docs/vm/damon/design: Update DAMON-Idle Page Tracking interference
handling
Docs/damon: Update outdated term 'regions update interval'
Documentation/admin-guide/mm/damon/usage.rst | 6 +-- Documentation/vm/damon/design.rst | 43 +++++++++++--------- Documentation/vm/damon/faq.rst | 2 +- 3 files changed, 27 insertions(+), 24 deletions(-)
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2.17.1
SeongJae Park
maintainerPATCH 1/3 Docs/vm/damon: Call low level monitoring primitives the operations
DAMON code calls the low level monitoring primitives implementations the monitoring operations. The documentation would have no problem at still calling those primitives implementation because there is no real difference in the concepts, but making it more consistent with the code would make it better. This commit therefore convert sentences in the doc specifically pointing the implementations of the primitives to call it monitoring operations.
Signed-off-by SeongJae Park <[email protected]>
--- Documentation/vm/damon/design.rst | 24 ++++++++++++------------ Documentation/vm/damon/faq.rst | 2 +- 2 files changed, 13 insertions(+), 13 deletions(-)
Documentation/vm/damon/design.rst +12 -12
@@ -13,12 +13,13 @@ primitives that dependent on and optimized for the target address space. On the other hand, the accuracy and overhead tradeoff mechanism, which is the core of DAMON, is in the pure logic space. DAMON separates the two parts in different layers and defines its interface to allow various low level -primitives implementations configurable with the core logic. +primitives implementations configurable with the core logic. We call the low +level primitives implementations monitoring operations. Due to this separated design and the configurable interface, users can extend -DAMON for any address space by configuring the core logics with appropriate low -level primitive implementations. If appropriate one is not provided, users can -implement the primitives on their own. +DAMON for any address space by configuring the core logics with appropriate +monitoring operations. If appropriate one is not provided, users can implement +the operations on their own. For example, physical memory, virtual memory, swap space, those for specific processes, NUMA nodes, files, and backing memory devices would be supportable.
@@ -26,25 +27,24 @@ Also, if some architectures or devices support special optimized access check primitives, those will be easily configurable. -Reference Implementations of Address Space Specific Primitives -============================================================== +Reference Implementations of Address Space Specific Monitoring Operations +========================================================================= -The low level primitives for the fundamental access monitoring are defined in -two parts: +The monitoring operations are defined in two parts: 1. Identification of the monitoring target address range for the address space. 2. Access check of specific address range in the target space. -DAMON currently provides the implementations of the primitives for the physical +DAMON currently provides the implementations of the operations for the physical and virtual address spaces. Below two subsections describe how those work. VMA-based Target Address Range Construction ------------------------------------------- -This is only for the virtual address space primitives implementation. That for -the physical address space simply asks users to manually set the monitoring -target address ranges. +This is only for the virtual address space monitoring operations +implementation. That for the physical address space simply asks users to +manually set the monitoring target address ranges. Only small parts in the super-huge virtual address space of the processes are mapped to the physical memory and accessed. Thus, tracking the unmapped
Documentation/vm/damon/faq.rst +1 -1
@@ -31,7 +31,7 @@ Does DAMON support virtual memory only? ======================================= No. The core of the DAMON is address space independent. The address space -specific low level primitive parts including monitoring target regions +specific monitoring operations including monitoring target regions constructions and actual access checks can be implemented and configured on the DAMON core by the users. In this way, DAMON users can monitor any address space with any access check technique.
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2.17.1
SeongJae Park
maintainerPATCH 2/3 Docs/vm/damon/design: Update DAMON-Idle Page Tracking interference handling
In reply to SeongJae ParkIn DAMON's early development stage before it be merged in the mainline, it was first designed to work exclusively with Idle page tracking to avoid any interference between each other. Later, but still before be merged in the mainline, because Idle page tracking is fully under the control of sysadmins, we made the resolving of conflict as the responsibility of sysadmins. The document is not updated for the change, though. This commit updates the document for that.
Signed-off-by SeongJae Park <[email protected]>
--- Documentation/vm/damon/design.rst | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
Documentation/vm/damon/design.rst +4 -3
@@ -84,9 +84,10 @@ table having a mapping to the address. In this way, the implementations find and clear the bit(s) for next sampling target address and checks whether the bit(s) set again after one sampling period. This could disturb other kernel subsystems using the Accessed bits, namely Idle page tracking and the reclaim -logic. To avoid such disturbances, DAMON makes it mutually exclusive with Idle -page tracking and uses ``PG_idle`` and ``PG_young`` page flags to solve the -conflict with the reclaim logic, as Idle page tracking does. +logic. DAMON does nothing to avoid disturbing Idle page tracking, so handling +the interference is the responsibility of sysadmins. However, it solves the +conflict with the reclaim logic using ``PG_idle`` and ``PG_young`` page flags, +as Idle page tracking does. Address Space Independent Core Mechanisms
Signature · 1 line
2.17.1
SeongJae Park
maintainerPATCH 3/3 Docs/damon: Update outdated term 'regions update interval'
In reply to SeongJae ParkBefore DAMON is merged in the mainline, the concept of 'regions update interval' has generalized to be used as the time interval for update of any monitoring operations related data structure, but the document has not updated properly. This commit updates the document for better consistency.
Signed-off-by SeongJae Park <[email protected]>
--- Documentation/admin-guide/mm/damon/usage.rst | 6 +++--- Documentation/vm/damon/design.rst | 12 +++++++----- 2 files changed, 10 insertions(+), 8 deletions(-)
Documentation/admin-guide/mm/damon/usage.rst +3 -3
@@ -47,7 +47,7 @@ Attributes ---------- Users can get and set the ``sampling interval``, ``aggregation interval``, -``regions update interval``, and min/max number of monitoring target regions by +``update interval``, and min/max number of monitoring target regions by reading from and writing to the ``attrs`` file. To know about the monitoring attributes in detail, please refer to the :doc:`/vm/damon/design`. For example, below commands set those values to 5 ms, 100 ms, 1,000 ms, 10 and
@@ -128,8 +128,8 @@ ranges, ``20-40`` and ``50-100`` as that of pid 4242, which is the second one Note that this sets the initial monitoring target regions only. In case of virtual memory monitoring, DAMON will automatically updates the boundary of the -regions after one ``regions update interval``. Therefore, users should set the -``regions update interval`` large enough in this case, if they don't want the +regions after one ``update interval``. Therefore, users should set the +``update interval`` large enough in this case, if they don't want the update.
Documentation/vm/damon/design.rst +7 -5
@@ -95,8 +95,8 @@ Address Space Independent Core Mechanisms Below four sections describe each of the DAMON core mechanisms and the five monitoring attributes, ``sampling interval``, ``aggregation interval``, -``regions update interval``, ``minimum number of regions``, and ``maximum -number of regions``. +``update interval``, ``minimum number of regions``, and ``maximum number of +regions``. Access Frequency Monitoring
@@ -169,6 +169,8 @@ The monitoring target address range could dynamically changed. For example, virtual memory could be dynamically mapped and unmapped. Physical memory could be hot-plugged. -As the changes could be quite frequent in some cases, DAMON checks the dynamic -memory mapping changes and applies it to the abstracted target area only for -each of a user-specified time interval (``regions update interval``). +As the changes could be quite frequent in some cases, DAMON allows the +monitoring operations to check dynamic changes including memory mapping changes +and applies it to monitoring operations-related data structures such as the +abstracted monitoring target memory area only for each of a user-specified time +interval (``update interval``).
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2.17.1