| Message ID | 20231213182729.587081-3-shr@devkernel.io (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm/ksm: Add ksm advisor | expand |
On 13.12.23 19:27, Stefan Roesch wrote: > This adds four new knobs for the KSM advisor to influence its behaviour. > > The knobs are: > - advisor_mode: > none: no advisor (default) > scan-time: scan time advisor > - advisor_max_cpu: 70 (default, cpu usage percent) > - advisor_min_pages_to_scan: 500 (default) > - advisor_max_pages_to_scan: 30000 (default) > - advisor_target_scan_time: 200 (default in seconds) > > The new values will take effect on the next scan round. > > Signed-off-by: Stefan Roesch <shr@devkernel.io> > --- > mm/ksm.c | 142 +++++++++++++++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 139 insertions(+), 3 deletions(-) > > diff --git a/mm/ksm.c b/mm/ksm.c > index 4f7b71a1f3112..f7387a6d02050 100644 > --- a/mm/ksm.c > +++ b/mm/ksm.c > @@ -302,10 +302,10 @@ unsigned long ksm_zero_pages; > static unsigned long ksm_pages_skipped; > > /* Don't scan more than max pages per batch. */ > -static unsigned long ksm_advisor_max_pages = 30000; > +static unsigned long ksm_advisor_max_pages_to_scan = 30000; > > /* At least scan this many pages per batch. */ > -static unsigned long ksm_advisor_min_pages = 500; > +static unsigned long ksm_advisor_min_pages_to_scan = 500; > That renaming should go into the previous patch. > /* Min CPU for scanning pages per scan */ > static unsigned int ksm_advisor_min_cpu = 10; > @@ -341,6 +341,16 @@ enum ksm_advisor_type { > }; > static enum ksm_advisor_type ksm_advisor; > > +static void set_advisor_defaults(void) > +{ > + if (ksm_advisor == KSM_ADVISOR_NONE) { > + ksm_thread_pages_to_scan = DEFAULT_PAGES_TO_SCAN; > + } else if (ksm_advisor == KSM_ADVISOR_SCAN_TIME) { > + advisor_ctx = (const struct advisor_ctx){ 0 }; > + ksm_thread_pages_to_scan = ksm_advisor_min_pages_to_scan; > + } > +} > + > static inline void advisor_start_scan(void) > { > if (ksm_advisor == KSM_ADVISOR_SCAN_TIME) > @@ -434,7 +444,7 @@ static void scan_time_advisor(void) > > pages = min(pages, per_page_cost * ksm_advisor_max_cpu); > pages = max(pages, per_page_cost * ksm_advisor_min_cpu); > - pages = min(pages, ksm_advisor_max_pages); > + pages = min(pages, ksm_advisor_max_pages_to_scan); > > /* Update advisor context */ > advisor_ctx.change = change; > @@ -3722,6 +3732,127 @@ static ssize_t smart_scan_store(struct kobject *kobj, > } > KSM_ATTR(smart_scan); > > +static ssize_t advisor_mode_show(struct kobject *kobj, > + struct kobj_attribute *attr, char *buf) > +{ > + const char *output; > + > + if (ksm_advisor == KSM_ADVISOR_NONE) > + output = "[none] scan-time"; > + else if (ksm_advisor == KSM_ADVISOR_SCAN_TIME) > + output = "none [scan-time]"; > + > + return sysfs_emit(buf, "%s\n", output); > +} > + > +static ssize_t advisor_mode_store(struct kobject *kobj, > + struct kobj_attribute *attr, const char *buf, > + size_t count) > +{ > + if (sysfs_streq("scan-time", buf)) > + ksm_advisor = KSM_ADVISOR_SCAN_TIME; > + else if (sysfs_streq("none", buf)) > + ksm_advisor = KSM_ADVISOR_NONE; > + else > + return -EINVAL; > + > + /* Set advisor default values */ > + set_advisor_defaults(); It probably makes sense to not reset the defaults if the ksm_advisor didn't change. Apart form that, LGTM.
On Mon, Dec 18, 2023, at 3:25 AM, David Hildenbrand wrote: > On 13.12.23 19:27, Stefan Roesch wrote: >> This adds four new knobs for the KSM advisor to influence its behaviour. >> >> The knobs are: >> - advisor_mode: >> none: no advisor (default) >> scan-time: scan time advisor >> - advisor_max_cpu: 70 (default, cpu usage percent) >> - advisor_min_pages_to_scan: 500 (default) >> - advisor_max_pages_to_scan: 30000 (default) >> - advisor_target_scan_time: 200 (default in seconds) >> >> The new values will take effect on the next scan round. >> >> Signed-off-by: Stefan Roesch <shr@devkernel.io> >> --- >> mm/ksm.c | 142 +++++++++++++++++++++++++++++++++++++++++++++++++++++-- >> 1 file changed, 139 insertions(+), 3 deletions(-) >> >> diff --git a/mm/ksm.c b/mm/ksm.c >> index 4f7b71a1f3112..f7387a6d02050 100644 >> --- a/mm/ksm.c >> +++ b/mm/ksm.c >> @@ -302,10 +302,10 @@ unsigned long ksm_zero_pages; >> static unsigned long ksm_pages_skipped; >> >> /* Don't scan more than max pages per batch. */ >> -static unsigned long ksm_advisor_max_pages = 30000; >> +static unsigned long ksm_advisor_max_pages_to_scan = 30000; >> >> /* At least scan this many pages per batch. */ >> -static unsigned long ksm_advisor_min_pages = 500; >> +static unsigned long ksm_advisor_min_pages_to_scan = 500; >> > > That renaming should go into the previous patch. > Moved it to the previous patch. >> /* Min CPU for scanning pages per scan */ >> static unsigned int ksm_advisor_min_cpu = 10; >> @@ -341,6 +341,16 @@ enum ksm_advisor_type { >> }; >> static enum ksm_advisor_type ksm_advisor; >> >> +static void set_advisor_defaults(void) >> +{ >> + if (ksm_advisor == KSM_ADVISOR_NONE) { >> + ksm_thread_pages_to_scan = DEFAULT_PAGES_TO_SCAN; >> + } else if (ksm_advisor == KSM_ADVISOR_SCAN_TIME) { >> + advisor_ctx = (const struct advisor_ctx){ 0 }; >> + ksm_thread_pages_to_scan = ksm_advisor_min_pages_to_scan; >> + } >> +} >> + >> static inline void advisor_start_scan(void) >> { >> if (ksm_advisor == KSM_ADVISOR_SCAN_TIME) >> @@ -434,7 +444,7 @@ static void scan_time_advisor(void) >> >> pages = min(pages, per_page_cost * ksm_advisor_max_cpu); >> pages = max(pages, per_page_cost * ksm_advisor_min_cpu); >> - pages = min(pages, ksm_advisor_max_pages); >> + pages = min(pages, ksm_advisor_max_pages_to_scan); >> >> /* Update advisor context */ >> advisor_ctx.change = change; >> @@ -3722,6 +3732,127 @@ static ssize_t smart_scan_store(struct kobject *kobj, >> } >> KSM_ATTR(smart_scan); >> >> +static ssize_t advisor_mode_show(struct kobject *kobj, >> + struct kobj_attribute *attr, char *buf) >> +{ >> + const char *output; >> + >> + if (ksm_advisor == KSM_ADVISOR_NONE) >> + output = "[none] scan-time"; >> + else if (ksm_advisor == KSM_ADVISOR_SCAN_TIME) >> + output = "none [scan-time]"; >> + >> + return sysfs_emit(buf, "%s\n", output); >> +} >> + >> +static ssize_t advisor_mode_store(struct kobject *kobj, >> + struct kobj_attribute *attr, const char *buf, >> + size_t count) >> +{ >> + if (sysfs_streq("scan-time", buf)) >> + ksm_advisor = KSM_ADVISOR_SCAN_TIME; >> + else if (sysfs_streq("none", buf)) >> + ksm_advisor = KSM_ADVISOR_NONE; >> + else >> + return -EINVAL; >> + >> + /* Set advisor default values */ >> + set_advisor_defaults(); > > It probably makes sense to not reset the defaults if the ksm_advisor > didn't change. > Added the above change. > Apart form that, LGTM. > > -- > Cheers, > > David / dhildenb
diff --git a/mm/ksm.c b/mm/ksm.c index 4f7b71a1f3112..f7387a6d02050 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -302,10 +302,10 @@ unsigned long ksm_zero_pages; static unsigned long ksm_pages_skipped; /* Don't scan more than max pages per batch. */ -static unsigned long ksm_advisor_max_pages = 30000; +static unsigned long ksm_advisor_max_pages_to_scan = 30000; /* At least scan this many pages per batch. */ -static unsigned long ksm_advisor_min_pages = 500; +static unsigned long ksm_advisor_min_pages_to_scan = 500; /* Min CPU for scanning pages per scan */ static unsigned int ksm_advisor_min_cpu = 10; @@ -341,6 +341,16 @@ enum ksm_advisor_type { }; static enum ksm_advisor_type ksm_advisor; +static void set_advisor_defaults(void) +{ + if (ksm_advisor == KSM_ADVISOR_NONE) { + ksm_thread_pages_to_scan = DEFAULT_PAGES_TO_SCAN; + } else if (ksm_advisor == KSM_ADVISOR_SCAN_TIME) { + advisor_ctx = (const struct advisor_ctx){ 0 }; + ksm_thread_pages_to_scan = ksm_advisor_min_pages_to_scan; + } +} + static inline void advisor_start_scan(void) { if (ksm_advisor == KSM_ADVISOR_SCAN_TIME) @@ -434,7 +444,7 @@ static void scan_time_advisor(void) pages = min(pages, per_page_cost * ksm_advisor_max_cpu); pages = max(pages, per_page_cost * ksm_advisor_min_cpu); - pages = min(pages, ksm_advisor_max_pages); + pages = min(pages, ksm_advisor_max_pages_to_scan); /* Update advisor context */ advisor_ctx.change = change; @@ -3722,6 +3732,127 @@ static ssize_t smart_scan_store(struct kobject *kobj, } KSM_ATTR(smart_scan); +static ssize_t advisor_mode_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + const char *output; + + if (ksm_advisor == KSM_ADVISOR_NONE) + output = "[none] scan-time"; + else if (ksm_advisor == KSM_ADVISOR_SCAN_TIME) + output = "none [scan-time]"; + + return sysfs_emit(buf, "%s\n", output); +} + +static ssize_t advisor_mode_store(struct kobject *kobj, + struct kobj_attribute *attr, const char *buf, + size_t count) +{ + if (sysfs_streq("scan-time", buf)) + ksm_advisor = KSM_ADVISOR_SCAN_TIME; + else if (sysfs_streq("none", buf)) + ksm_advisor = KSM_ADVISOR_NONE; + else + return -EINVAL; + + /* Set advisor default values */ + set_advisor_defaults(); + + return count; +} +KSM_ATTR(advisor_mode); + +static ssize_t advisor_max_cpu_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sysfs_emit(buf, "%u\n", ksm_advisor_max_cpu); +} + +static ssize_t advisor_max_cpu_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + int err; + unsigned long value; + + err = kstrtoul(buf, 10, &value); + if (err) + return -EINVAL; + + ksm_advisor_max_cpu = value; + return count; +} +KSM_ATTR(advisor_max_cpu); + +static ssize_t advisor_min_pages_to_scan_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sysfs_emit(buf, "%lu\n", ksm_advisor_min_pages_to_scan); +} + +static ssize_t advisor_min_pages_to_scan_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + int err; + unsigned long value; + + err = kstrtoul(buf, 10, &value); + if (err) + return -EINVAL; + + ksm_advisor_min_pages_to_scan = value; + return count; +} +KSM_ATTR(advisor_min_pages_to_scan); + +static ssize_t advisor_max_pages_to_scan_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sysfs_emit(buf, "%lu\n", ksm_advisor_max_pages_to_scan); +} + +static ssize_t advisor_max_pages_to_scan_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + int err; + unsigned long value; + + err = kstrtoul(buf, 10, &value); + if (err) + return -EINVAL; + + ksm_advisor_max_pages_to_scan = value; + return count; +} +KSM_ATTR(advisor_max_pages_to_scan); + +static ssize_t advisor_target_scan_time_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sysfs_emit(buf, "%lu\n", ksm_advisor_target_scan_time); +} + +static ssize_t advisor_target_scan_time_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + int err; + unsigned long value; + + err = kstrtoul(buf, 10, &value); + if (err) + return -EINVAL; + if (value < 1) + return -EINVAL; + + ksm_advisor_target_scan_time = value; + return count; +} +KSM_ATTR(advisor_target_scan_time); + static struct attribute *ksm_attrs[] = { &sleep_millisecs_attr.attr, &pages_to_scan_attr.attr, @@ -3744,6 +3875,11 @@ static struct attribute *ksm_attrs[] = { &use_zero_pages_attr.attr, &general_profit_attr.attr, &smart_scan_attr.attr, + &advisor_mode_attr.attr, + &advisor_max_cpu_attr.attr, + &advisor_min_pages_to_scan_attr.attr, + &advisor_max_pages_to_scan_attr.attr, + &advisor_target_scan_time_attr.attr, NULL, };
This adds four new knobs for the KSM advisor to influence its behaviour. The knobs are: - advisor_mode: none: no advisor (default) scan-time: scan time advisor - advisor_max_cpu: 70 (default, cpu usage percent) - advisor_min_pages_to_scan: 500 (default) - advisor_max_pages_to_scan: 30000 (default) - advisor_target_scan_time: 200 (default in seconds) The new values will take effect on the next scan round. Signed-off-by: Stefan Roesch <shr@devkernel.io> --- mm/ksm.c | 142 +++++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 139 insertions(+), 3 deletions(-)