From: SeongJae Park sj@kernel.org
mainline inclusion from mainline-5.16 commit 1cd2430300594a230dba9178ac9e286d868d9da2 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I4GVMK CVE: NA
------------------------------------------------- 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 (cherry picked from commit 1cd2430300594a230dba9178ac9e286d868d9da2) Signed-off-by: Yue Zou zouyue3@huawei.com Reviewed-by: Kefeng Wang wangkefeng.wang@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- include/linux/damon.h | 25 +++++++++++++++++++----- mm/damon/core.c | 45 ++++++++++++++++++++++++++++++++++++++----- 2 files changed, 60 insertions(+), 10 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; diff --git a/mm/damon/core.c b/mm/damon/core.c index 693b75bc3450..d1da4bef96ed 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -107,8 +107,12 @@ struct damos *damon_new_scheme( scheme->stat_sz = 0; INIT_LIST_HEAD(&scheme->list);
+ scheme->quota.ms = quota->ms; scheme->quota.sz = quota->sz; scheme->quota.reset_interval = quota->reset_interval; + scheme->quota.total_charged_sz = 0; + scheme->quota.total_charged_ns = 0; + scheme->quota.esz = 0; scheme->quota.charged_sz = 0; scheme->quota.charged_from = 0; scheme->quota.charge_target_from = NULL; @@ -550,9 +554,10 @@ static void damon_do_apply_schemes(struct damon_ctx *c, damon_for_each_scheme(s, c) { struct damos_quota *quota = &s->quota; unsigned long sz = r->ar.end - r->ar.start; + struct timespec64 begin, end;
/* Check the quota */ - if (quota->sz && quota->charged_sz >= quota->sz) + if (quota->esz && quota->charged_sz >= quota->esz) continue;
/* Skip previously charged regions */ @@ -597,16 +602,21 @@ static void damon_do_apply_schemes(struct damon_ctx *c,
/* Apply the scheme */ if (c->primitive.apply_scheme) { - if (quota->sz && quota->charged_sz + sz > quota->sz) { - sz = ALIGN_DOWN(quota->sz - quota->charged_sz, + if (quota->esz && + quota->charged_sz + sz > quota->esz) { + sz = ALIGN_DOWN(quota->esz - quota->charged_sz, DAMON_MIN_REGION); if (!sz) goto update_stat; damon_split_region_at(c, t, r, sz); } + ktime_get_coarse_ts64(&begin); c->primitive.apply_scheme(c, t, r, s); + ktime_get_coarse_ts64(&end); + quota->total_charged_ns += timespec64_to_ns(&end) - + timespec64_to_ns(&begin); quota->charged_sz += sz; - if (quota->sz && quota->charged_sz >= quota->sz) { + if (quota->esz && quota->charged_sz >= quota->esz) { quota->charge_target_from = t; quota->charge_addr_from = r->ar.end + 1; } @@ -620,6 +630,29 @@ static void damon_do_apply_schemes(struct damon_ctx *c, } }
+/* Shouldn't be called if quota->ms and quota->sz are zero */ +static void damos_set_effective_quota(struct damos_quota *quota) +{ + unsigned long throughput; + unsigned long esz; + + if (!quota->ms) { + quota->esz = quota->sz; + return; + } + + if (quota->total_charged_ns) + throughput = quota->total_charged_sz * 1000000 / + quota->total_charged_ns; + else + throughput = PAGE_SIZE * 1024; + esz = throughput * quota->ms; + + if (quota->sz && quota->sz < esz) + esz = quota->sz; + quota->esz = esz; +} + static void kdamond_apply_schemes(struct damon_ctx *c) { struct damon_target *t; @@ -629,15 +662,17 @@ static void kdamond_apply_schemes(struct damon_ctx *c) damon_for_each_scheme(s, c) { struct damos_quota *quota = &s->quota;
- if (!quota->sz) + if (!quota->ms && !quota->sz) continue;
/* New charge window starts */ if (time_after_eq(jiffies, quota->charged_from + msecs_to_jiffies( quota->reset_interval))) { + quota->total_charged_sz += quota->charged_sz; quota->charged_from = jiffies; quota->charged_sz = 0; + damos_set_effective_quota(quota); } }