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Add a target_order field to express per-order mTHP collapse intent. Zero means system default (PMD order, same as current behavior). Valid values are 0 and 2..HPAGE_PMD_ORDER. Wire up the sysfs interface: a per-scheme rw file "target_order". Validate at store time that the value is in range, and warn at scheme creation time if DAMOS_COLLAPSE is used with an unsupported non-PMD order, resetting to 0. The actual mTHP application via the khugepaged wrapper will be added in subsequent patches. Co-developed-by: Kunwu Chan Signed-off-by: Kunwu Chan Signed-off-by: Lian Wang Signed-off-by: Lian Wang --- include/linux/damon.h | 5 ++++ mm/damon/core.c | 2 ++ mm/damon/sysfs-schemes.c | 61 ++++++++++++++++++++++++++++++++++++++++ 3 files changed, 68 insertions(+) diff --git a/include/linux/damon.h b/include/linux/damon.h index 6f7edb3590ef..5a0587556573 100644 --- a/include/linux/damon.h +++ b/include/linux/damon.h @@ -572,6 +572,11 @@ struct damos_migrate_dests { struct damos { struct damos_access_pattern pattern; enum damos_action action; + /* + * @target_order: target order for mTHP actions (DAMOS_COLLAPSE). + * 0 means system default (PMD order). Valid: 0, 2..HPAGE_PMD_ORDER. + */ + unsigned int target_order; unsigned long apply_interval_us; /* private: internal use only */ /* diff --git a/mm/damon/core.c b/mm/damon/core.c index 265d51ade25b..be54defd4646 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -579,6 +579,7 @@ struct damos *damon_new_scheme(struct damos_access_pattern *pattern, scheme->migrate_dests = (struct damos_migrate_dests){}; scheme->target_nid = target_nid; + scheme->target_order = 0; return scheme; } @@ -1278,6 +1279,7 @@ static int damos_commit(struct damos *dst, struct damos *src) dst->wmarks = src->wmarks; dst->target_nid = src->target_nid; + dst->target_order = src->target_order; err = damos_commit_dests(&dst->migrate_dests, &src->migrate_dests); if (err) diff --git a/mm/damon/sysfs-schemes.c b/mm/damon/sysfs-schemes.c index 329cfd0bbe9f..7dcd582ded86 100644 --- a/mm/damon/sysfs-schemes.c +++ b/mm/damon/sysfs-schemes.c @@ -6,7 +6,9 @@ */ #include +#include #include +#include #include "sysfs-common.h" @@ -2257,6 +2259,7 @@ struct damon_sysfs_scheme { struct damon_sysfs_stats *stats; struct damon_sysfs_scheme_regions *tried_regions; int target_nid; + unsigned int target_order; struct damos_sysfs_dests *dests; }; @@ -2323,6 +2326,7 @@ static struct damon_sysfs_scheme *damon_sysfs_scheme_alloc( scheme->action = action; scheme->apply_interval_us = apply_interval_us; scheme->target_nid = NUMA_NO_NODE; + scheme->target_order = 0; return scheme; } @@ -2642,6 +2646,39 @@ static ssize_t target_nid_store(struct kobject *kobj, return err ? err : count; } +static ssize_t target_order_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + struct damon_sysfs_scheme *scheme = container_of(kobj, + struct damon_sysfs_scheme, kobj); + + return sysfs_emit(buf, "%u\n", scheme->target_order); +} + +static ssize_t target_order_store(struct kobject *kobj, + struct kobj_attribute *attr, const char *buf, size_t count) +{ + struct damon_sysfs_scheme *scheme = container_of(kobj, + struct damon_sysfs_scheme, kobj); + unsigned int val; + int err; + + err = kstrtouint(buf, 0, &val); + if (err) + return err; + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE + if (val != 0 && (val < 2 || val > HPAGE_PMD_ORDER)) + return -EINVAL; +#else + if (val != 0) + return -EINVAL; +#endif + + scheme->target_order = val; + return count; +} + static void damon_sysfs_scheme_release(struct kobject *kobj) { kfree(container_of(kobj, struct damon_sysfs_scheme, kobj)); @@ -2656,10 +2693,14 @@ static struct kobj_attribute damon_sysfs_scheme_apply_interval_us_attr = static struct kobj_attribute damon_sysfs_scheme_target_nid_attr = __ATTR_RW_MODE(target_nid, 0600); +static struct kobj_attribute damon_sysfs_scheme_target_order_attr = + __ATTR_RW_MODE(target_order, 0600); + static struct attribute *damon_sysfs_scheme_attrs[] = { &damon_sysfs_scheme_action_attr.attr, &damon_sysfs_scheme_apply_interval_us_attr.attr, &damon_sysfs_scheme_target_nid_attr.attr, + &damon_sysfs_scheme_target_order_attr.attr, NULL, }; ATTRIBUTE_GROUPS(damon_sysfs_scheme); @@ -2970,6 +3011,7 @@ static struct damos *damon_sysfs_mk_scheme( struct damon_sysfs_weights *sysfs_weights = sysfs_quotas->weights; struct damon_sysfs_watermarks *sysfs_wmarks = sysfs_scheme->watermarks; struct damos *scheme; + unsigned int target_order; int err; struct damos_access_pattern pattern = { @@ -3005,6 +3047,25 @@ static struct damos *damon_sysfs_mk_scheme( if (!scheme) return NULL; + target_order = sysfs_scheme->target_order; + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE + if (sysfs_scheme->action == DAMOS_COLLAPSE && + target_order != 0 && + target_order != HPAGE_PMD_ORDER) { + pr_warn("DAMON collapse: target_order %u not supported, only PMD order (%u) is available. Use 0 or %u.\n", + target_order, + HPAGE_PMD_ORDER, HPAGE_PMD_ORDER); + target_order = 0; + } +#else + if (sysfs_scheme->action == DAMOS_COLLAPSE && target_order != 0) { + pr_warn("DAMON collapse: target_order not supported without THP. Use 0.\n"); + target_order = 0; + } +#endif + scheme->target_order = target_order; + err = damos_sysfs_add_quota_score(sysfs_quotas->goals, &scheme->quota); if (err) { damon_destroy_scheme(scheme);