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authorSeongJae Park <sj@kernel.org>2021-11-05 13:47:23 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-11-06 13:30:45 -0700
commit1cd2430300594a230dba9178ac9e286d868d9da2 (patch)
tree1896f6ebfc67d13b3733ba66910f68dd78dd2f9a /include/linux/damon.h
parent50585192bc2ef9309d32dabdbb5e735679f4f128 (diff)
mm/damon/schemes: implement time quota
The size quota feature of DAMOS is useful for IO resource-critical systems, but not so intuitive for CPU time-critical systems. Systems using zram or zswap-like swap device would be examples. To provide another intuitive ways for such systems, this implements time-based quota for DAMON-based Operation Schemes. If the quota is set, DAMOS tries to use only up to the user-defined quota of CPU time within a given time window. Link: https://lkml.kernel.org/r/20211019150731.16699-5-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Cc: Amit Shah <amit@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: David Hildenbrand <david@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: David Woodhouse <dwmw@amazon.com> Cc: Greg Thelen <gthelen@google.com> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Leonard Foerster <foersleo@amazon.de> Cc: Marco Elver <elver@google.com> Cc: Markus Boehme <markubo@amazon.de> Cc: Shakeel Butt <shakeelb@google.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/damon.h')
-rw-r--r--include/linux/damon.h25
1 files changed, 20 insertions, 5 deletions
diff --git a/include/linux/damon.h b/include/linux/damon.h
index 585d985768fd..1e7671bf3d23 100644
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -91,20 +91,35 @@ enum damos_action {
/**
* struct damos_quota - Controls the aggressiveness of the given scheme.
+ * @ms: Maximum milliseconds that the scheme can use.
* @sz: Maximum bytes of memory that the action can be applied.
* @reset_interval: Charge reset interval in milliseconds.
*
* To avoid consuming too much CPU time or IO resources for applying the
- * &struct damos->action to large memory, DAMON allows users to set a size
- * quota. The quota can be set by writing non-zero values to &sz. If the size
- * quota is set, DAMON tries to apply the action only up to &sz bytes within
- * &reset_interval.
+ * &struct damos->action to large memory, DAMON allows users to set time and/or
+ * size quotas. The quotas can be set by writing non-zero values to &ms and
+ * &sz, respectively. If the time quota is set, DAMON tries to use only up to
+ * &ms milliseconds within &reset_interval for applying the action. If the
+ * size quota is set, DAMON tries to apply the action only up to &sz bytes
+ * within &reset_interval.
+ *
+ * Internally, the time quota is transformed to a size quota using estimated
+ * throughput of the scheme's action. DAMON then compares it against &sz and
+ * uses smaller one as the effective quota.
*/
struct damos_quota {
+ unsigned long ms;
unsigned long sz;
unsigned long reset_interval;
-/* private: For charging the quota */
+/* private: */
+ /* For throughput estimation */
+ unsigned long total_charged_sz;
+ unsigned long total_charged_ns;
+
+ unsigned long esz; /* Effective size quota in bytes */
+
+ /* For charging the quota */
unsigned long charged_sz;
unsigned long charged_from;
struct damon_target *charge_target_from;