From: SeongJae Park sj@kernel.org
mainline inclusion from mainline-5.16 commit 2f0b548c9f03a78f4ce6ab48986e3108028936a6 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I4GVMK CVE: NA
------------------------------------------------- To tune the DAMON-based operation schemes, knowing how many and how large regions are affected by each of the schemes will be helful. Those stats could be used for not only the tuning, but also monitoring of the working set size and the number of regions, if the scheme does not change the program behavior too much.
For the reason, this implements the statistics for the schemes. The total number and size of the regions that each scheme is applied are exported to users via '->stat_count' and '->stat_sz' of 'struct damos'. Admins can also check the number by reading 'schemes' debugfs file. The last two integers now represents the stats. To allow collecting the stats without changing the program behavior, this also adds new scheme action, 'DAMOS_STAT'. Note that 'DAMOS_STAT' is not only making no memory operation actions, but also does not reset the age of regions.
Link: https://lkml.kernel.org/r/20211001125604.29660-6-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 Rienjes 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 2f0b548c9f03a78f4ce6ab48986e3108028936a6) 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 | 10 +++++++++- mm/damon/core.c | 7 ++++++- mm/damon/dbgfs.c | 5 +++-- mm/damon/vaddr.c | 2 ++ 4 files changed, 20 insertions(+), 4 deletions(-)
diff --git a/include/linux/damon.h b/include/linux/damon.h index be6b6e81e8ee..f301bb53381c 100644 --- a/include/linux/damon.h +++ b/include/linux/damon.h @@ -78,6 +78,7 @@ struct damon_target { * @DAMOS_PAGEOUT: Call ``madvise()`` for the region with MADV_PAGEOUT. * @DAMOS_HUGEPAGE: Call ``madvise()`` for the region with MADV_HUGEPAGE. * @DAMOS_NOHUGEPAGE: Call ``madvise()`` for the region with MADV_NOHUGEPAGE. + * @DAMOS_STAT: Do nothing but count the stat. */ enum damos_action { DAMOS_WILLNEED, @@ -85,6 +86,7 @@ enum damos_action { DAMOS_PAGEOUT, DAMOS_HUGEPAGE, DAMOS_NOHUGEPAGE, + DAMOS_STAT, /* Do nothing but only record the stat */ };
/** @@ -96,9 +98,13 @@ enum damos_action { * @min_age_region: Minimum age of target regions. * @max_age_region: Maximum age of target regions. * @action: &damo_action to be applied to the target regions. + * @stat_count: Total number of regions that this scheme is applied. + * @stat_sz: Total size of regions that this scheme is applied. * @list: List head for siblings. * - * Note that both the minimums and the maximums are inclusive. + * For each aggregation interval, DAMON applies @action to monitoring target + * regions fit in the condition and updates the statistics. Note that both + * the minimums and the maximums are inclusive. */ struct damos { unsigned long min_sz_region; @@ -108,6 +114,8 @@ struct damos { unsigned int min_age_region; unsigned int max_age_region; enum damos_action action; + unsigned long stat_count; + unsigned long stat_sz; struct list_head list; };
diff --git a/mm/damon/core.c b/mm/damon/core.c index 0ed97b21cbb6..2f6785737902 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -103,6 +103,8 @@ struct damos *damon_new_scheme( scheme->min_age_region = min_age_region; scheme->max_age_region = max_age_region; scheme->action = action; + scheme->stat_count = 0; + scheme->stat_sz = 0; INIT_LIST_HEAD(&scheme->list);
return scheme; @@ -544,9 +546,12 @@ static void damon_do_apply_schemes(struct damon_ctx *c, continue; if (r->age < s->min_age_region || s->max_age_region < r->age) continue; + s->stat_count++; + s->stat_sz += sz; if (c->primitive.apply_scheme) c->primitive.apply_scheme(c, t, r, s); - r->age = 0; + if (s->action != DAMOS_STAT) + r->age = 0; } }
diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c index 78b7a04490c5..28d6abf27763 100644 --- a/mm/damon/dbgfs.c +++ b/mm/damon/dbgfs.c @@ -106,11 +106,11 @@ static ssize_t sprint_schemes(struct damon_ctx *c, char *buf, ssize_t len)
damon_for_each_scheme(s, c) { rc = scnprintf(&buf[written], len - written, - "%lu %lu %u %u %u %u %d\n", + "%lu %lu %u %u %u %u %d %lu %lu\n", s->min_sz_region, s->max_sz_region, s->min_nr_accesses, s->max_nr_accesses, s->min_age_region, s->max_age_region, - s->action); + s->action, s->stat_count, s->stat_sz); if (!rc) return -ENOMEM;
@@ -159,6 +159,7 @@ static bool damos_action_valid(int action) case DAMOS_PAGEOUT: case DAMOS_HUGEPAGE: case DAMOS_NOHUGEPAGE: + case DAMOS_STAT: return true; default: return false; diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c index 3e1c74d36bab..953c145b4f08 100644 --- a/mm/damon/vaddr.c +++ b/mm/damon/vaddr.c @@ -705,6 +705,8 @@ int damon_va_apply_scheme(struct damon_ctx *ctx, struct damon_target *t, case DAMOS_NOHUGEPAGE: madv_action = MADV_NOHUGEPAGE; break; + case DAMOS_STAT: + return 0; default: pr_warn("Wrong action %d\n", scheme->action); return -EINVAL;