| Message ID | 20220223152051.22936-1-sj@kernel.org |
|---|---|
| Headers | show |
| Series | Introduce DAMON sysfs interface | expand |
On Wed, Feb 23, 2022 at 03:20:42PM +0000, SeongJae Park wrote: > +static struct kobj_attribute damon_sysfs_ul_range_min_attr = > + __ATTR(min, 0600, damon_sysfs_ul_range_min_show, > + damon_sysfs_ul_range_min_store); > + > +static struct kobj_attribute damon_sysfs_ul_range_max_attr = > + __ATTR(max, 0600, damon_sysfs_ul_range_max_show, > + damon_sysfs_ul_range_max_store); Can you use __ATTR_RW_MODE() instead here and elsewhere? thanks, greg k-h
Hi, SeongJae: On 2/23/22 11:20 PM, SeongJae Park wrote: > DAMON's debugfs-based user interface served very well, so far. However, > it unnecessarily depends on debugfs, while DAMON is not aimed to be used > for only debugging. Also, the interface receives multiple values via > one file. For example, schemes file receives 18 values separated by > white spaces. As a result, it is ineffient, hard to be used, and > difficult to be extended. Especially, keeping backward compatibility of > user space tools is getting only challenging. It would be better to > implement another reliable and flexible interface and deprecate the > debugfs interface in long term. > > To this end, this commit implements a stub of a part of the new user > interface of DAMON using sysfs. Specifically, this commit implements > the sysfs control parts for virtual address space monitoring. > > More specifically, the idea of the new interface is, using directory > hierarchies and making one file for one value. The hierarchy that this > commit is introducing is as below. In the below figure, > parents-children relations are represented with indentations, each > directory is having ``/`` suffix, and files in each directory are > separated by comma (","). > > /sys/kernel/mm/damon/admin > │ kdamonds/nr > │ │ 0/state,pid > │ │ │ contexts/nr > │ │ │ │ 0/operations > │ │ │ │ │ monitoring_attrs/ > │ │ │ │ │ │ intervals/sample_us,aggr_us,update_us > │ │ │ │ │ │ nr_regions/min,max > │ │ │ │ │ targets/nr > │ │ │ │ │ │ 0/pid > │ │ │ │ │ │ ... > │ │ │ │ ... > │ │ ... > > Writing a number <N> to each 'nr' file makes directories of name <0> to > <N-1> in the directory of the 'nr' file. That's all this commit does. > Writing proper values to relevant files will construct the DAMON > contexts, and writing a special keyword, 'on', to 'state' files for each > kdamond will ask DAMON to start the constructed contexts. > > For a short example, using below commands for > monitoring virtual address spaces of a given workload is imaginable: > > # cd /sys/kernel/mm/damon/admin/ > # echo 1 > kdamonds/nr > # echo 1 > kdamonds/0/contexts/nr > # echo vaddr > kdamonds/0/contexts/0/damon_type > # echo 1 > kdamonds/0/contexts/0/targets/nr > # echo $(pidof <workload>) > kdamonds/0/contexts/0/targets/0/pid > # echo on > kdamonds/0/state I do some test about the sys interface, like this: [root@rt2k03395 0]# tree . ├── contexts │ ├── 0 │ │ ├── monitoring_attrs │ │ │ ├── intervals │ │ │ │ ├── aggr_us │ │ │ │ ├── sample_us │ │ │ │ └── update_us │ │ │ └── nr_regions │ │ │ ├── max │ │ │ └── min │ │ ├── operations │ │ ├── schemes │ │ │ └── nr │ │ └── targets │ │ ├── 0 │ │ │ ├── pid │ │ │ └── regions │ │ │ ├── 0 │ │ │ │ ├── end │ │ │ │ └── start │ │ │ ├── 1 │ │ │ │ ├── end │ │ │ │ └── start │ │ │ ├── 10 │ │ │ │ ├── end │ │ │ │ └── start │ │ │ ├── 11 │ │ │ │ ├── end │ │ │ │ └── start │ │ │ ├── 12 cd regions/ [root@rt2k03395 regions]# ls 0 10 12 14 16 18 2 21 23 25 27 29 30 32 34 36 38 4 41 43 45 47 49 6 8 nr 1 11 13 15 17 19 20 22 24 26 28 3 31 33 35 37 39 40 42 44 46 48 5 7 9 [root@rt2k03395 regions]# cd 44/cat * [root@rt2k03395 regions/44]# cat * 0 0 I'm skeptical about the number regions ? And after manually setting the number of nr, the processing of "start" and "end" will be very troublesome,I guess you might want to do some special region addresses, such as hot or cold region, Is that true ？But I think you need to think about how do you deal with too many uncontacted reigons that need to be done. > Please note that this commit is implementing only the sysfs part stub as > abovely mentioned. This commit doesn't implement the special keywords > for 'state' files. Following commits will do that. > > Signed-off-by: SeongJae Park <sj@kernel.org> > --- > mm/damon/Kconfig | 7 + > mm/damon/Makefile | 1 + > mm/damon/sysfs.c | 1059 +++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 1067 insertions(+) > create mode 100644 mm/damon/sysfs.c > > diff --git a/mm/damon/Kconfig b/mm/damon/Kconfig > index 01bad77ad7ae..9b559c76d6dd 100644 > --- a/mm/damon/Kconfig > +++ b/mm/damon/Kconfig > @@ -52,6 +52,13 @@ config DAMON_VADDR_KUNIT_TEST > > If unsure, say N. > > +config DAMON_SYSFS > + bool "DAMON sysfs interface" > + depends on DAMON && SYSFS > + help > + This builds the sysfs interface for DAMON. The user space can use > + the interface for arbitrary data access monitoring. > + > config DAMON_DBGFS > bool "DAMON debugfs interface" > depends on DAMON_VADDR && DAMON_PADDR && DEBUG_FS > diff --git a/mm/damon/Makefile b/mm/damon/Makefile > index aebbf6c14c51..dbf7190b4144 100644 > --- a/mm/damon/Makefile > +++ b/mm/damon/Makefile > @@ -3,5 +3,6 @@ > obj-y := core.o > obj-$(CONFIG_DAMON_VADDR) += ops-common.o vaddr.o > obj-$(CONFIG_DAMON_PADDR) += ops-common.o paddr.o > +obj-$(CONFIG_DAMON_SYSFS) += sysfs.o > obj-$(CONFIG_DAMON_DBGFS) += dbgfs.o > obj-$(CONFIG_DAMON_RECLAIM) += reclaim.o > diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c > new file mode 100644 > index 000000000000..e8087ffd924c > --- /dev/null > +++ b/mm/damon/sysfs.c > @@ -0,0 +1,1059 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * DAMON sysfs Interface > + * > + * Copyright (c) 2022 SeongJae Park <sj@kernel.org> > + */ > + > +#include <linux/damon.h> > +#include <linux/kobject.h> > +#include <linux/pid.h> > +#include <linux/sched.h> > +#include <linux/slab.h> > + > +static DEFINE_MUTEX(damon_sysfs_lock); > + > +/* > + * unsigned long range directory > + */ > + > +struct damon_sysfs_ul_range { > + struct kobject kobj; > + unsigned long min; > + unsigned long max; > +}; > + > +static struct damon_sysfs_ul_range *damon_sysfs_ul_range_alloc( > + unsigned long min, > + unsigned long max) > +{ > + struct damon_sysfs_ul_range *range = kmalloc(sizeof(*range), > + GFP_KERNEL); > + > + if (!range) > + return NULL; > + range->kobj = (struct kobject){}; > + range->min = min; > + range->max = max; > + > + return range; > +} > + > +static ssize_t damon_sysfs_ul_range_min_show(struct kobject *kobj, > + struct kobj_attribute *attr, char *buf) > +{ > + struct damon_sysfs_ul_range *range = container_of(kobj, > + struct damon_sysfs_ul_range, kobj); > + > + return sysfs_emit(buf, "%lu\n", range->min); > +} > + > +static ssize_t damon_sysfs_ul_range_min_store(struct kobject *kobj, > + struct kobj_attribute *attr, const char *buf, size_t count) > +{ > + struct damon_sysfs_ul_range *range = container_of(kobj, > + struct damon_sysfs_ul_range, kobj); > + unsigned long min; > + int err; > + > + err = kstrtoul(buf, 0, &min); > + if (err) > + return -EINVAL; > + > + range->min = min; > + return count; > +} > + > +static ssize_t damon_sysfs_ul_range_max_show(struct kobject *kobj, > + struct kobj_attribute *attr, char *buf) > +{ > + struct damon_sysfs_ul_range *range = container_of(kobj, > + struct damon_sysfs_ul_range, kobj); > + > + return sysfs_emit(buf, "%lu\n", range->max); > +} > + > +static ssize_t damon_sysfs_ul_range_max_store(struct kobject *kobj, > + struct kobj_attribute *attr, const char *buf, size_t count) > +{ > + struct damon_sysfs_ul_range *range = container_of(kobj, > + struct damon_sysfs_ul_range, kobj); > + unsigned long max; > + int err; > + > + err = kstrtoul(buf, 0, &max); > + if (err) > + return -EINVAL; > + > + range->max = max; > + return count; > +} > + > +static void damon_sysfs_ul_range_release(struct kobject *kobj) > +{ > + kfree(container_of(kobj, struct damon_sysfs_ul_range, kobj)); > +} > + > +static struct kobj_attribute damon_sysfs_ul_range_min_attr = > + __ATTR(min, 0600, damon_sysfs_ul_range_min_show, > + damon_sysfs_ul_range_min_store); > + > +static struct kobj_attribute damon_sysfs_ul_range_max_attr = > + __ATTR(max, 0600, damon_sysfs_ul_range_max_show, > + damon_sysfs_ul_range_max_store); > + > +static struct attribute *damon_sysfs_ul_range_attrs[] = { > + &damon_sysfs_ul_range_min_attr.attr, > + &damon_sysfs_ul_range_max_attr.attr, > + NULL, > +}; > +ATTRIBUTE_GROUPS(damon_sysfs_ul_range); > + > +static struct kobj_type damon_sysfs_ul_range_ktype = { > + .release = damon_sysfs_ul_range_release, > + .sysfs_ops = &kobj_sysfs_ops, > + .default_groups = damon_sysfs_ul_range_groups, > +}; > + > +/* > + * target directory > + */ > + > +struct damon_sysfs_target { > + struct kobject kobj; > + int pid; > +}; > + > +static struct damon_sysfs_target *damon_sysfs_target_alloc(void) > +{ > + return kzalloc(sizeof(struct damon_sysfs_target), GFP_KERNEL); > +} > + > +static ssize_t damon_sysfs_target_pid_show(struct kobject *kobj, > + struct kobj_attribute *attr, char *buf) > +{ > + struct damon_sysfs_target *target = container_of(kobj, > + struct damon_sysfs_target, kobj); > + > + return sysfs_emit(buf, "%d\n", target->pid); > +} > + > +static ssize_t damon_sysfs_target_pid_store(struct kobject *kobj, > + struct kobj_attribute *attr, const char *buf, size_t count) > +{ > + struct damon_sysfs_target *target = container_of(kobj, > + struct damon_sysfs_target, kobj); > + int err = kstrtoint(buf, 0, &target->pid); > + > + if (err) > + return -EINVAL; > + return count; > +} > + > +static void damon_sysfs_target_release(struct kobject *kobj) > +{ > + kfree(container_of(kobj, struct damon_sysfs_target, kobj)); > +} > + > +static struct kobj_attribute damon_sysfs_target_pid_attr = __ATTR(pid, 0600, > + damon_sysfs_target_pid_show, damon_sysfs_target_pid_store); > + > +static struct attribute *damon_sysfs_target_attrs[] = { > + &damon_sysfs_target_pid_attr.attr, > + NULL, > +}; > +ATTRIBUTE_GROUPS(damon_sysfs_target); > + > +static struct kobj_type damon_sysfs_target_ktype = { > + .release = damon_sysfs_target_release, > + .sysfs_ops = &kobj_sysfs_ops, > + .default_groups = damon_sysfs_target_groups, > +}; > + > +/* > + * targets directory > + */ > + > +struct damon_sysfs_targets { > + struct kobject kobj; > + struct damon_sysfs_target **targets_arr; > + int nr; > +}; > + > +static struct damon_sysfs_targets *damon_sysfs_targets_alloc(void) > +{ > + return kzalloc(sizeof(struct damon_sysfs_targets), GFP_KERNEL); > +} > + > +static void damon_sysfs_targets_rm_dirs(struct damon_sysfs_targets *targets) > +{ > + struct damon_sysfs_target **targets_arr = targets->targets_arr; > + int i; > + > + for (i = 0; i < targets->nr; i++) > + kobject_put(&targets_arr[i]->kobj); > + targets->nr = 0; > + kfree(targets_arr); > + targets->targets_arr = NULL; > +} > + > +static int damon_sysfs_targets_add_dirs(struct damon_sysfs_targets *targets, > + int nr_targets) > +{ > + struct damon_sysfs_target **targets_arr, *target; > + int err, i; > + > + damon_sysfs_targets_rm_dirs(targets); > + if (!nr_targets) > + return 0; > + > + targets_arr = kmalloc_array(nr_targets, sizeof(*targets_arr), > + GFP_KERNEL | __GFP_NOWARN); > + if (!targets_arr) > + return -ENOMEM; > + targets->targets_arr = targets_arr; > + > + for (i = 0; i < nr_targets; i++) { > + target = damon_sysfs_target_alloc(); > + if (!target) { > + damon_sysfs_targets_rm_dirs(targets); > + return -ENOMEM; > + } > + > + err = kobject_init_and_add(&target->kobj, > + &damon_sysfs_target_ktype, &targets->kobj, > + "%d", i); > + if (err) > + goto out; > + > + targets_arr[i] = target; > + targets->nr++; > + } > + return 0; > + > +out: > + damon_sysfs_targets_rm_dirs(targets); > + kobject_put(&target->kobj); > + return err; > +} > + > +static ssize_t damon_sysfs_targets_nr_show(struct kobject *kobj, > + struct kobj_attribute *attr, char *buf) > +{ > + struct damon_sysfs_targets *targets = container_of(kobj, > + struct damon_sysfs_targets, kobj); > + > + return sysfs_emit(buf, "%d\n", targets->nr); > +} > + > +static ssize_t damon_sysfs_targets_nr_store(struct kobject *kobj, > + struct kobj_attribute *attr, const char *buf, size_t count) > +{ > + struct damon_sysfs_targets *targets = container_of(kobj, > + struct damon_sysfs_targets, kobj); > + int nr, err = kstrtoint(buf, 0, &nr); > + > + if (err) > + return err; > + if (nr < 0) > + return -EINVAL; > + > + if (!mutex_trylock(&damon_sysfs_lock)) > + return -EBUSY; > + err = damon_sysfs_targets_add_dirs(targets, nr); > + mutex_unlock(&damon_sysfs_lock); > + if (err) > + return err; > + > + return count; > +} > + > +static void damon_sysfs_targets_release(struct kobject *kobj) > +{ > + kfree(container_of(kobj, struct damon_sysfs_targets, kobj)); > +} > + > +static struct kobj_attribute damon_sysfs_targets_nr_attr = __ATTR(nr, 0600, > + damon_sysfs_targets_nr_show, damon_sysfs_targets_nr_store); > + > +static struct attribute *damon_sysfs_targets_attrs[] = { > + &damon_sysfs_targets_nr_attr.attr, > + NULL, > +}; > +ATTRIBUTE_GROUPS(damon_sysfs_targets); > + > +static struct kobj_type damon_sysfs_targets_ktype = { > + .release = damon_sysfs_targets_release, > + .sysfs_ops = &kobj_sysfs_ops, > + .default_groups = damon_sysfs_targets_groups, > +}; > + > +/* > + * intervals directory > + */ > + > +struct damon_sysfs_intervals { > + struct kobject kobj; > + unsigned long sample_us; > + unsigned long aggr_us; > + unsigned long update_us; > +}; > + > +static struct damon_sysfs_intervals *damon_sysfs_intervals_alloc( > + unsigned long sample_us, unsigned long aggr_us, > + unsigned long update_us) > +{ > + struct damon_sysfs_intervals *intervals = kmalloc(sizeof(*intervals), > + GFP_KERNEL); > + > + if (!intervals) > + return NULL; > + > + intervals->kobj = (struct kobject){}; > + intervals->sample_us = sample_us; > + intervals->aggr_us = aggr_us; > + intervals->update_us = update_us; > + return intervals; > +} > + > +static ssize_t damon_sysfs_intervals_sample_us_show(struct kobject *kobj, > + struct kobj_attribute *attr, char *buf) > +{ > + struct damon_sysfs_intervals *intervals = container_of(kobj, > + struct damon_sysfs_intervals, kobj); > + > + return sysfs_emit(buf, "%lu\n", intervals->sample_us); > +} > + > +static ssize_t damon_sysfs_intervals_sample_us_store(struct kobject *kobj, > + struct kobj_attribute *attr, const char *buf, size_t count) > +{ > + struct damon_sysfs_intervals *intervals = container_of(kobj, > + struct damon_sysfs_intervals, kobj); > + unsigned long us; > + int err = kstrtoul(buf, 0, &us); > + > + if (err) > + return -EINVAL; > + > + intervals->sample_us = us; > + return count; > +} > + > +static ssize_t damon_sysfs_intervals_aggr_us_show(struct kobject *kobj, > + struct kobj_attribute *attr, char *buf) > +{ > + struct damon_sysfs_intervals *intervals = container_of(kobj, > + struct damon_sysfs_intervals, kobj); > + > + return sysfs_emit(buf, "%lu\n", intervals->aggr_us); > +} > + > +static ssize_t damon_sysfs_intervals_aggr_us_store(struct kobject *kobj, > + struct kobj_attribute *attr, const char *buf, size_t count) > +{ > + struct damon_sysfs_intervals *intervals = container_of(kobj, > + struct damon_sysfs_intervals, kobj); > + unsigned long us; > + int err = kstrtoul(buf, 0, &us); > + > + if (err) > + return -EINVAL; > + > + intervals->aggr_us = us; > + return count; > +} > + > +static ssize_t damon_sysfs_intervals_update_us_show(struct kobject *kobj, > + struct kobj_attribute *attr, char *buf) > +{ > + struct damon_sysfs_intervals *intervals = container_of(kobj, > + struct damon_sysfs_intervals, kobj); > + > + return sysfs_emit(buf, "%lu\n", intervals->update_us); > +} > + > +static ssize_t damon_sysfs_intervals_update_us_store(struct kobject *kobj, > + struct kobj_attribute *attr, const char *buf, size_t count) > +{ > + struct damon_sysfs_intervals *intervals = container_of(kobj, > + struct damon_sysfs_intervals, kobj); > + unsigned long us; > + int err = kstrtoul(buf, 0, &us); > + > + if (err) > + return -EINVAL; > + > + intervals->update_us = us; > + return count; > +} > + > +static void damon_sysfs_intervals_release(struct kobject *kobj) > +{ > + kfree(container_of(kobj, struct damon_sysfs_intervals, kobj)); > +} > + > +static struct kobj_attribute damon_sysfs_intervals_sample_us_attr = > + __ATTR(sample_us, 0600, > + damon_sysfs_intervals_sample_us_show, > + damon_sysfs_intervals_sample_us_store); > + > +static struct kobj_attribute damon_sysfs_intervals_aggr_us_attr = > + __ATTR(aggr_us, 0600, > + damon_sysfs_intervals_aggr_us_show, > + damon_sysfs_intervals_aggr_us_store); > + > +static struct kobj_attribute damon_sysfs_intervals_update_us_attr = > + __ATTR(update_us, 0600, > + damon_sysfs_intervals_update_us_show, > + damon_sysfs_intervals_update_us_store); > + > +static struct attribute *damon_sysfs_intervals_attrs[] = { > + &damon_sysfs_intervals_sample_us_attr.attr, > + &damon_sysfs_intervals_aggr_us_attr.attr, > + &damon_sysfs_intervals_update_us_attr.attr, > + NULL, > +}; > +ATTRIBUTE_GROUPS(damon_sysfs_intervals); > + > +static struct kobj_type damon_sysfs_intervals_ktype = { > + .release = damon_sysfs_intervals_release, > + .sysfs_ops = &kobj_sysfs_ops, > + .default_groups = damon_sysfs_intervals_groups, > +}; > + > +/* > + * monitoring_attrs directory > + */ > + > +struct damon_sysfs_attrs { > + struct kobject kobj; > + struct damon_sysfs_intervals *intervals; > + struct damon_sysfs_ul_range *nr_regions_range; > +}; > + > +static struct damon_sysfs_attrs *damon_sysfs_attrs_alloc(void) > +{ > + struct damon_sysfs_attrs *attrs = kmalloc(sizeof(*attrs), GFP_KERNEL); > + > + if (!attrs) > + return NULL; > + attrs->kobj = (struct kobject){}; > + return attrs; > +} > + > +static int damon_sysfs_attrs_add_dirs(struct damon_sysfs_attrs *attrs) > +{ > + struct damon_sysfs_intervals *intervals; > + struct damon_sysfs_ul_range *nr_regions_range; > + int err; > + > + intervals = damon_sysfs_intervals_alloc(5000, 100000, 60000000); > + if (!intervals) > + return -ENOMEM; > + > + err = kobject_init_and_add(&intervals->kobj, > + &damon_sysfs_intervals_ktype, &attrs->kobj, > + "intervals"); > + if (err) > + goto put_intervals_out; > + attrs->intervals = intervals; > + > + nr_regions_range = damon_sysfs_ul_range_alloc(10, 1000); > + if (!nr_regions_range) > + goto put_intervals_out; > + > + err = kobject_init_and_add(&nr_regions_range->kobj, > + &damon_sysfs_ul_range_ktype, &attrs->kobj, > + "nr_regions"); > + if (err) > + goto put_nr_regions_intervals_out; > + attrs->nr_regions_range = nr_regions_range; > + return 0; > + > +put_nr_regions_intervals_out: > + kobject_put(&nr_regions_range->kobj); > + attrs->nr_regions_range = NULL; > +put_intervals_out: > + kobject_put(&intervals->kobj); > + attrs->intervals = NULL; > + return err; > +} > + > +static void damon_sysfs_attrs_rm_dirs(struct damon_sysfs_attrs *attrs) > +{ > + kobject_put(&attrs->nr_regions_range->kobj); > + kobject_put(&attrs->intervals->kobj); > +} > + > +static void damon_sysfs_attrs_release(struct kobject *kobj) > +{ > + kfree(container_of(kobj, struct damon_sysfs_attrs, kobj)); > +} > + > +static struct attribute *damon_sysfs_attrs_attrs[] = { > + NULL, > +}; > +ATTRIBUTE_GROUPS(damon_sysfs_attrs); > + > +static struct kobj_type damon_sysfs_attrs_ktype = { > + .release = damon_sysfs_attrs_release, > + .sysfs_ops = &kobj_sysfs_ops, > + .default_groups = damon_sysfs_attrs_groups, > +}; > + > +/* > + * context directory > + */ > + > +/* This should match with enum damon_ops_id */ > +static const char * const damon_sysfs_ops_strs[] = { > + "vaddr", > + "paddr", > +}; > + > +struct damon_sysfs_context { > + struct kobject kobj; > + enum damon_ops_id ops_id; > + struct damon_sysfs_attrs *attrs; > + struct damon_sysfs_targets *targets; > +}; > + > +static struct damon_sysfs_context *damon_sysfs_context_alloc( > + enum damon_ops_id ops_id) > +{ > + struct damon_sysfs_context *context = kmalloc(sizeof(*context), > + GFP_KERNEL); > + > + if (!context) > + return NULL; > + context->kobj = (struct kobject){}; > + context->ops_id = ops_id; > + return context; > +} > + > +static int damon_sysfs_context_set_attrs(struct damon_sysfs_context *context) > +{ > + struct damon_sysfs_attrs *attrs = damon_sysfs_attrs_alloc(); > + int err; > + > + if (!attrs) > + return -ENOMEM; > + err = kobject_init_and_add(&attrs->kobj, &damon_sysfs_attrs_ktype, > + &context->kobj, "monitoring_attrs"); > + if (err) > + goto out; > + err = damon_sysfs_attrs_add_dirs(attrs); > + if (err) > + goto out; > + context->attrs = attrs; > + return 0; > + > +out: > + kobject_put(&attrs->kobj); > + return err; > +} > + > +static int damon_sysfs_context_set_targets(struct damon_sysfs_context *context) > +{ > + struct damon_sysfs_targets *targets = damon_sysfs_targets_alloc(); > + int err; > + > + if (!targets) > + return -ENOMEM; > + err = kobject_init_and_add(&targets->kobj, &damon_sysfs_targets_ktype, > + &context->kobj, "targets"); > + if (err) { > + kobject_put(&targets->kobj); > + return err; > + } > + context->targets = targets; > + return 0; > +} > + > +static int damon_sysfs_context_add_dirs(struct damon_sysfs_context *context) > +{ > + int err; > + > + err = damon_sysfs_context_set_attrs(context); > + if (err) > + return err; > + > + err = damon_sysfs_context_set_targets(context); > + if (err) > + goto put_attrs_out; > + > + return 0; > + > +put_attrs_out: > + kobject_put(&context->attrs->kobj); > + context->attrs = NULL; > + return err; > +} > + > +static void damon_sysfs_context_rm_dirs(struct damon_sysfs_context *context) > +{ > + damon_sysfs_attrs_rm_dirs(context->attrs); > + kobject_put(&context->attrs->kobj); > + damon_sysfs_targets_rm_dirs(context->targets); > + kobject_put(&context->targets->kobj); > +} > + > +static ssize_t damon_sysfs_context_operations_show(struct kobject *kobj, > + struct kobj_attribute *attr, char *buf) > +{ > + struct damon_sysfs_context *context = container_of(kobj, > + struct damon_sysfs_context, kobj); > + > + return sysfs_emit(buf, "%s\n", damon_sysfs_ops_strs[context->ops_id]); > +} > + > +static ssize_t damon_sysfs_context_operations_store(struct kobject *kobj, > + struct kobj_attribute *attr, const char *buf, size_t count) > +{ > + struct damon_sysfs_context *context = container_of(kobj, > + struct damon_sysfs_context, kobj); > + > + if (sysfs_streq(buf, damon_sysfs_ops_strs[DAMON_OPS_VADDR])) { > + context->ops_id = DAMON_OPS_VADDR; > + return count; > + } > + return -EINVAL; > +} > + > +static void damon_sysfs_context_release(struct kobject *kobj) > +{ > + kfree(container_of(kobj, struct damon_sysfs_context, kobj)); > +} > + > +static struct kobj_attribute damon_sysfs_context_operations_attr = __ATTR( > + operations, 0600, damon_sysfs_context_operations_show, > + damon_sysfs_context_operations_store); > + > +static struct attribute *damon_sysfs_context_attrs[] = { > + &damon_sysfs_context_operations_attr.attr, > + NULL, > +}; > +ATTRIBUTE_GROUPS(damon_sysfs_context); > + > +static struct kobj_type damon_sysfs_context_ktype = { > + .release = damon_sysfs_context_release, > + .sysfs_ops = &kobj_sysfs_ops, > + .default_groups = damon_sysfs_context_groups, > +}; > + > +/* > + * contexts directory > + */ > + > +struct damon_sysfs_contexts { > + struct kobject kobj; > + struct damon_sysfs_context **contexts_arr; > + int nr; > +}; > + > +static struct damon_sysfs_contexts *damon_sysfs_contexts_alloc(void) > +{ > + return kzalloc(sizeof(struct damon_sysfs_contexts), GFP_KERNEL); > +} > + > +static void damon_sysfs_contexts_rm_dirs(struct damon_sysfs_contexts *contexts) > +{ > + struct damon_sysfs_context **contexts_arr = contexts->contexts_arr; > + int i; > + > + for (i = 0; i < contexts->nr; i++) { > + damon_sysfs_context_rm_dirs(contexts_arr[i]); > + kobject_put(&contexts_arr[i]->kobj); > + } > + contexts->nr = 0; > + kfree(contexts_arr); > + contexts->contexts_arr = NULL; > +} > + > +static int damon_sysfs_contexts_add_dirs(struct damon_sysfs_contexts *contexts, > + int nr_contexts) > +{ > + struct damon_sysfs_context **contexts_arr, *context; > + int err, i; > + > + damon_sysfs_contexts_rm_dirs(contexts); > + if (!nr_contexts) > + return 0; > + > + contexts_arr = kmalloc_array(nr_contexts, sizeof(*contexts_arr), > + GFP_KERNEL | __GFP_NOWARN); > + if (!contexts_arr) > + return -ENOMEM; > + contexts->contexts_arr = contexts_arr; > + > + for (i = 0; i < nr_contexts; i++) { > + context = damon_sysfs_context_alloc(DAMON_OPS_VADDR); > + if (!context) { > + damon_sysfs_contexts_rm_dirs(contexts); > + return -ENOMEM; > + } > + > + err = kobject_init_and_add(&context->kobj, > + &damon_sysfs_context_ktype, &contexts->kobj, > + "%d", i); > + if (err) > + goto out; > + > + err = damon_sysfs_context_add_dirs(context); > + if (err) > + goto out; > + > + contexts_arr[i] = context; > + contexts->nr++; > + } > + return 0; > + > +out: > + damon_sysfs_contexts_rm_dirs(contexts); > + kobject_put(&context->kobj); > + return err; > +} > + > +static ssize_t damon_sysfs_contexts_nr_show(struct kobject *kobj, > + struct kobj_attribute *attr, char *buf) > +{ > + struct damon_sysfs_contexts *contexts = container_of(kobj, > + struct damon_sysfs_contexts, kobj); > + > + return sysfs_emit(buf, "%d\n", contexts->nr); > +} > + > +static ssize_t damon_sysfs_contexts_nr_store(struct kobject *kobj, > + struct kobj_attribute *attr, const char *buf, size_t count) > +{ > + struct damon_sysfs_contexts *contexts = container_of(kobj, > + struct damon_sysfs_contexts, kobj); > + int nr, err; > + > + err = kstrtoint(buf, 0, &nr); > + if (err) > + return err; > + /* TODO: support multiple contexts per kdamond */ > + if (nr < 0 || 1 < nr) > + return -EINVAL; > + > + if (!mutex_trylock(&damon_sysfs_lock)) > + return -EBUSY; > + err = damon_sysfs_contexts_add_dirs(contexts, nr); > + mutex_unlock(&damon_sysfs_lock); > + if (err) > + return err; > + > + return count; > +} > + > +static void damon_sysfs_contexts_release(struct kobject *kobj) > +{ > + kfree(container_of(kobj, struct damon_sysfs_contexts, kobj)); > +} > + > +static struct kobj_attribute damon_sysfs_contexts_nr_attr = __ATTR(nr, 0600, > + damon_sysfs_contexts_nr_show, damon_sysfs_contexts_nr_store); > + > +static struct attribute *damon_sysfs_contexts_attrs[] = { > + &damon_sysfs_contexts_nr_attr.attr, > + NULL, > +}; > +ATTRIBUTE_GROUPS(damon_sysfs_contexts); > + > +static struct kobj_type damon_sysfs_contexts_ktype = { > + .release = damon_sysfs_contexts_release, > + .sysfs_ops = &kobj_sysfs_ops, > + .default_groups = damon_sysfs_contexts_groups, > +}; > + > +/* > + * kdamond directory > + */ > + > +struct damon_sysfs_kdamond { > + struct kobject kobj; > + struct damon_sysfs_contexts *contexts; > +}; > + > +static struct damon_sysfs_kdamond *damon_sysfs_kdamond_alloc(void) > +{ > + return kzalloc(sizeof(struct damon_sysfs_kdamond), GFP_KERNEL); > +} > + > +static int damon_sysfs_kdamond_add_dirs(struct damon_sysfs_kdamond *kdamond) > +{ > + struct damon_sysfs_contexts *contexts; > + int err; > + > + contexts = damon_sysfs_contexts_alloc(); > + if (!contexts) > + return -ENOMEM; > + > + err = kobject_init_and_add(&contexts->kobj, > + &damon_sysfs_contexts_ktype, &kdamond->kobj, > + "contexts"); > + if (err) { > + kobject_put(&contexts->kobj); > + return err; > + } > + kdamond->contexts = contexts; > + > + return err; > +} > + > +static void damon_sysfs_kdamond_rm_dirs(struct damon_sysfs_kdamond *kdamond) > +{ > + damon_sysfs_contexts_rm_dirs(kdamond->contexts); > + kobject_put(&kdamond->contexts->kobj); > +} > + > +static ssize_t damon_sysfs_kdamond_state_show(struct kobject *kobj, > + struct kobj_attribute *attr, char *buf) > +{ > + return sysfs_emit(buf, "off\n"); > +} > + > +static ssize_t damon_sysfs_kdamond_state_store(struct kobject *kobj, > + struct kobj_attribute *attr, const char *buf, size_t count) > +{ > + return count; > +} > + > +static ssize_t damon_sysfs_kdamond_pid_show(struct kobject *kobj, > + struct kobj_attribute *attr, char *buf) > +{ > + return sysfs_emit(buf, "-1\n"); > +} > + > +static void damon_sysfs_kdamond_release(struct kobject *kobj) > +{ > + kfree(container_of(kobj, struct damon_sysfs_kdamond, kobj)); > +} > + > +static struct kobj_attribute damon_sysfs_kdamond_state_attr = > + __ATTR(state, 0600, damon_sysfs_kdamond_state_show, > + damon_sysfs_kdamond_state_store); > + > +static struct kobj_attribute damon_sysfs_kdamond_pid_attr = __ATTR(pid, 0400, > + damon_sysfs_kdamond_pid_show, NULL); > + > +static struct attribute *damon_sysfs_kdamond_attrs[] = { > + &damon_sysfs_kdamond_state_attr.attr, > + &damon_sysfs_kdamond_pid_attr.attr, > + NULL, > +}; > +ATTRIBUTE_GROUPS(damon_sysfs_kdamond); > + > +static struct kobj_type damon_sysfs_kdamond_ktype = { > + .release = damon_sysfs_kdamond_release, > + .sysfs_ops = &kobj_sysfs_ops, > + .default_groups = damon_sysfs_kdamond_groups, > +}; > + > +/* > + * kdamonds directory > + */ > + > +struct damon_sysfs_kdamonds { > + struct kobject kobj; > + struct damon_sysfs_kdamond **kdamonds_arr; > + int nr; > +}; > + > +static struct damon_sysfs_kdamonds *damon_sysfs_kdamonds_alloc(void) > +{ > + return kzalloc(sizeof(struct damon_sysfs_kdamonds), GFP_KERNEL); > +} > + > +static void damon_sysfs_kdamonds_rm_dirs(struct damon_sysfs_kdamonds *kdamonds) > +{ > + struct damon_sysfs_kdamond **kdamonds_arr = kdamonds->kdamonds_arr; > + int i; > + > + for (i = 0; i < kdamonds->nr; i++) { > + damon_sysfs_kdamond_rm_dirs(kdamonds_arr[i]); > + kobject_put(&kdamonds_arr[i]->kobj); > + } > + kdamonds->nr = 0; > + kfree(kdamonds_arr); > + kdamonds->kdamonds_arr = NULL; > +} > + > +static int damon_sysfs_kdamonds_add_dirs(struct damon_sysfs_kdamonds *kdamonds, > + int nr_kdamonds) > +{ > + struct damon_sysfs_kdamond **kdamonds_arr, *kdamond; > + int err, i; > + > + damon_sysfs_kdamonds_rm_dirs(kdamonds); > + if (!nr_kdamonds) > + return 0; > + > + kdamonds_arr = kmalloc_array(nr_kdamonds, sizeof(*kdamonds_arr), > + GFP_KERNEL | __GFP_NOWARN); > + if (!kdamonds_arr) > + return -ENOMEM; > + kdamonds->kdamonds_arr = kdamonds_arr; > + > + for (i = 0; i < nr_kdamonds; i++) { > + kdamond = damon_sysfs_kdamond_alloc(); > + if (!kdamond) { > + damon_sysfs_kdamonds_rm_dirs(kdamonds); > + return -ENOMEM; > + } > + > + err = kobject_init_and_add(&kdamond->kobj, > + &damon_sysfs_kdamond_ktype, &kdamonds->kobj, > + "%d", i); > + if (err) > + goto out; > + > + err = damon_sysfs_kdamond_add_dirs(kdamond); > + if (err) > + goto out; > + > + kdamonds_arr[i] = kdamond; > + kdamonds->nr++; > + } > + return 0; > + > +out: > + damon_sysfs_kdamonds_rm_dirs(kdamonds); > + kobject_put(&kdamond->kobj); > + return err; > +} > + > +static ssize_t damon_sysfs_kdamonds_nr_show(struct kobject *kobj, > + struct kobj_attribute *attr, char *buf) > +{ > + struct damon_sysfs_kdamonds *kdamonds = container_of(kobj, > + struct damon_sysfs_kdamonds, kobj); > + > + return sysfs_emit(buf, "%d\n", kdamonds->nr); > +} > + > +static ssize_t damon_sysfs_kdamonds_nr_store(struct kobject *kobj, > + struct kobj_attribute *attr, const char *buf, size_t count) > +{ > + struct damon_sysfs_kdamonds *kdamonds = container_of(kobj, > + struct damon_sysfs_kdamonds, kobj); > + int nr, err; > + > + err = kstrtoint(buf, 0, &nr); > + if (err) > + return err; > + if (nr < 0) > + return -EINVAL; > + > + if (!mutex_trylock(&damon_sysfs_lock)) > + return -EBUSY; > + err = damon_sysfs_kdamonds_add_dirs(kdamonds, nr); > + mutex_unlock(&damon_sysfs_lock); > + if (err) > + return err; > + > + return count; > +} > + > +static void damon_sysfs_kdamonds_release(struct kobject *kobj) > +{ > + kfree(container_of(kobj, struct damon_sysfs_kdamonds, kobj)); > +} > + > +static struct kobj_attribute damon_sysfs_kdamonds_nr_attr = __ATTR(nr, 0600, > + damon_sysfs_kdamonds_nr_show, damon_sysfs_kdamonds_nr_store); > + > +static struct attribute *damon_sysfs_kdamonds_attrs[] = { > + &damon_sysfs_kdamonds_nr_attr.attr, > + NULL, > +}; > +ATTRIBUTE_GROUPS(damon_sysfs_kdamonds); > + > +static struct kobj_type damon_sysfs_kdamonds_ktype = { > + .release = damon_sysfs_kdamonds_release, > + .sysfs_ops = &kobj_sysfs_ops, > + .default_groups = damon_sysfs_kdamonds_groups, > +}; > + > +/* > + * damon user interface directory > + */ > + > +struct damon_sysfs_ui_dir { > + struct kobject kobj; > + struct damon_sysfs_kdamonds *kdamonds; > +}; > + > +static struct damon_sysfs_ui_dir *damon_sysfs_ui_dir_alloc(void) > +{ > + return kzalloc(sizeof(struct damon_sysfs_ui_dir), GFP_KERNEL); > +} > + > +static int damon_sysfs_ui_dir_add_dirs(struct damon_sysfs_ui_dir *ui_dir) > +{ > + struct damon_sysfs_kdamonds *kdamonds; > + int err; > + > + kdamonds = damon_sysfs_kdamonds_alloc(); > + if (!kdamonds) > + return -ENOMEM; > + > + err = kobject_init_and_add(&kdamonds->kobj, > + &damon_sysfs_kdamonds_ktype, &ui_dir->kobj, > + "kdamonds"); > + if (err) { > + kobject_put(&kdamonds->kobj); > + return err; > + } > + ui_dir->kdamonds = kdamonds; > + return err; > +} > + > +static void damon_sysfs_ui_dir_release(struct kobject *kobj) > +{ > + kfree(container_of(kobj, struct damon_sysfs_ui_dir, kobj)); > +} > + > +static struct attribute *damon_sysfs_ui_dir_attrs[] = { > + NULL, > +}; > +ATTRIBUTE_GROUPS(damon_sysfs_ui_dir); > + > +static struct kobj_type damon_sysfs_ui_dir_ktype = { > + .release = damon_sysfs_ui_dir_release, > + .sysfs_ops = &kobj_sysfs_ops, > + .default_groups = damon_sysfs_ui_dir_groups, > +}; > + > +static int __init damon_sysfs_init(void) > +{ > + struct kobject *damon_sysfs_root; > + struct damon_sysfs_ui_dir *admin; > + int err; > + > + damon_sysfs_root = kobject_create_and_add("damon", mm_kobj); > + if (!damon_sysfs_root) > + return -ENOMEM; > + > + admin = damon_sysfs_ui_dir_alloc(); > + if (!admin) { > + kobject_put(damon_sysfs_root); > + return -ENOMEM; > + } > + err = kobject_init_and_add(&admin->kobj, &damon_sysfs_ui_dir_ktype, > + damon_sysfs_root, "admin"); > + if (err) > + goto out; > + err = damon_sysfs_ui_dir_add_dirs(admin); > + if (err) > + goto out; > + return 0; > + > +out: > + kobject_put(&admin->kobj); > + kobject_put(damon_sysfs_root); > + return err; > +} > +subsys_initcall(damon_sysfs_init);
Hi SeongJae: On 2/23/22 11:20 PM, SeongJae Park wrote: > Chages from Previous Version (RFC) > ================================== > > Compared to the RFC version of this patchset > (https://lore.kernel.org/linux-mm/20220217161938.8874-1-sj@kernel.org/), this > version contains below changes. > > - Implement all DAMON debugfs interface providing features > - Writeup documents > - Add more selftests > > Introduction > ============ > > DAMON's debugfs-based user interface (DAMON_DBGFS) served very well, so far. > However, it unnecessarily depends on debugfs, while DAMON is not aimed to be > used for only debugging. Also, the interface receives multiple values via one > file. For example, schemes file receives 18 values. As a result, it is > inefficient, hard to be used, and difficult to be extended. Especially, > keeping backward compatibility of user space tools is getting only challenging. > It would be better to implement another reliable and flexible interface and > deprecate DAMON_DBGFS in long term. > > For the reason, this patchset introduces a sysfs-based new user interface of > DAMON. The idea of the new interface is, using directory hierarchies and > having one dedicated file for each value. For a short example, users can do > the virtual address monitoring via the interface as below: > > # cd /sys/kernel/mm/damon/admin/ > # echo 1 > kdamonds/nr > # echo 1 > kdamonds/0/contexts/nr > # echo vaddr > kdamonds/0/contexts/0/operations > # echo 1 > kdamonds/0/contexts/0/targets/nr > # echo $(pidof <workload>) > kdamonds/0/contexts/0/targets/0/pid > # echo on > kdamonds/0/state > > A brief representation of the files hierarchy of DAMON sysfs interface is as > below. Childs are represented with indentation, directories are having '/' > suffix, and files in each directory are separated by comma. > > /sys/kernel/mm/damon/admin > │ kdamonds/nr > │ │ 0/state,pid > │ │ │ contexts/nr > │ │ │ │ 0/operations > │ │ │ │ │ monitoring_attrs/ > │ │ │ │ │ │ intervals/sample_us,aggr_us,update_us > │ │ │ │ │ │ nr_regions/min,max > │ │ │ │ │ targets/nr > │ │ │ │ │ │ 0/pid > │ │ │ │ │ │ │ regions/nr > │ │ │ │ │ │ │ │ 0/start,end > │ │ │ │ │ │ │ │ ... > │ │ │ │ │ │ ... > │ │ │ │ │ schemes/nr > │ │ │ │ │ 0/action > │ │ │ │ │ │ access_pattern/ > │ │ │ │ │ │ │ sz/min,max > │ │ │ │ │ │ │ nr_accesses/min,max > │ │ │ │ │ │ │ age/min,max > │ │ │ │ │ │ quotas/ms,sz,reset_interval_ms > │ │ │ │ │ │ │ weights/sz,nr_accesses,age > │ │ │ │ │ │ watermarks/metric,interval_us,high,mid,low > │ │ │ │ │ │ stats/nr_tried,sz_tried,nr_applied,sz_applied,qt_exceeds > │ │ │ │ │ ... > │ │ ... > > Detailed usage of the files will be described in the final Documentation patch > of this patchset. The introduction of the sys DAMON interface makes DAMON seem more hierarchical, but it brings a problem. From a user's perspective, I find it difficult to operate. For example: step one: echo xxx > /sys/kernel/mm/damon/admin/kdamonds/0/contexts/0/targets/nr step two: echo /sys/kernel/mm/damon/admin/kdamonds/0/contexts/0/targets/nr/1/pid echo /sys/kernel/mm/damon/admin/kdamonds/0/contexts/0/targets/nr/0/pid ......... Alas, it is really too troublesome to operate, can you make it as simple as possible, perhaps by referring to the implementation of cgroup. > Main Difference Between DAMON_DBGFS and DAMON_SYSFS > --------------------------------------------------- > > At the moment, DAMON_DBGFS and DAMON_SYSFS provides same features. One > important difference between them is their exclusiveness. DAMON_DBGFS works in > an exclusive manner, so that no DAMON worker thread (kdamond) in the system can > run concurrently and interfere somehow. For the reason, DAMON_DBGFS asks users > to construct all monitoring contexts and start them at once. It's not a big > problem but makes the operation a little bit complex and unflexible. > > For more flexible usage, DAMON_SYSFS moves the responsibility of preventing any > possible interference to the admins and work in a non-exclusive manner. That > is, users can configure and start contexts one by one. Note that DAMON > respects both exclusive groups and non-exclusive groups of contexts, in a > manner similar to that of reader-writer locks. That is, if any exclusive > monitoring contexts (e.g., contexts that started via DAMON_DBGFS) are running, > DAMON_SYSFS does not start new contexts, and vice versa. > > Future Plan of DAMON_DBGFS Deprecation > ====================================== > > Once this patchset is merged, DAMON_DBGFS development will be frozen. That is, > we will maintain it to work as is now so that no users will be break. But, it > will not be extended to provide any new feature of DAMON. The support will be > continued only until next LTS release. After that, we will drop DAMON_DBGFS. > > User-space Tooling Compatibility > -------------------------------- > > As DAMON_SYSFS provides all features of DAMON_DBGFS, all user space tooling can > move to DAMON_SYSFS. As we will continue supporting DAMON_DBGFS until next LTS > kernel release, user space tools would have enough time to move to DAMON_SYSFS. > > The official user space tool, damo[1], is already supporting both DAMON_SYSFS > and DAMON_DBGFS. Both correctness tests[2] and performance tests[3] of DAMON > using DAMON_SYSFS also passed. > > [1] https://github.com/awslabs/damo > [2] https://github.com/awslabs/damon-tests/tree/master/corr > [3] https://github.com/awslabs/damon-tests/tree/master/perf > > Complete Git Tree > ================= > > You can get the complete git tree from > https://git.kernel.org/sj/h/damon/sysfs/patches/v1. > > Sequence of Patches > =================== > > First two patches (patches 1-2) make core changes for DAMON_SYSFS. The first > one (patch 1) allows non-exclusive DAMON contexts so that DAMON_SYSFS can work > in non-exclusive mode, while the second one (patch 2) adds size of DAMON enum > types so that DAMON API users can safely iterate the enums. > > Third patch (patch 3) implements basic sysfs stub for virtual address spaces > monitoring. Note that this implements only sysfs files and DAMON is not > linked. Fourth patch (patch 4) links the DAMON_SYSFS to DAMON so that users > can control DAMON using the sysfs files. > > Following six patches (patches 5-10) implements other DAMON features that > DAMON_DBGFS supports one by one (physical address space monitoring, DAMON-based > operation schemes, schemes quotas, schemes prioritization weights, schemes > watermarks, and schemes stats). > > Following patch (patch 11) adds a simple selftest for DAMON_SYSFS, and the > final one (patch 12) documents DAMON_SYSFS. > > SeongJae Park (12): > mm/damon/core: Allow non-exclusive DAMON start/stop > mm/damon/core: Add number of each enum type values > mm/damon: Implement a minimal stub for sysfs-based DAMON interface > mm/damon/sysfs: Link DAMON for virtual address spaces monitoring > mm/damon/sysfs: Support physical address space monitoring > mm/damon/sysfs: Support DAMON-based Operation Schemes > mm/damon/sysfs: Support DAMOS quotas > mm/damon/sysfs: Support schemes prioritization weights > mm/damon/sysfs: Support DAMOS watermarks > mm/damon/sysfs: Support DAMOS stats > selftests/damon: Add a test for DAMON sysfs interface > Docs/admin-guide/mm/damon/usage: Document DAMON sysfs interface > > Documentation/admin-guide/mm/damon/usage.rst | 349 ++- > include/linux/damon.h | 6 +- > mm/damon/Kconfig | 7 + > mm/damon/Makefile | 1 + > mm/damon/core.c | 23 +- > mm/damon/dbgfs.c | 2 +- > mm/damon/reclaim.c | 2 +- > mm/damon/sysfs.c | 2684 ++++++++++++++++++ > tools/testing/selftests/damon/Makefile | 1 + > tools/testing/selftests/damon/sysfs.sh | 306 ++ > 10 files changed, 3364 insertions(+), 17 deletions(-) > create mode 100644 mm/damon/sysfs.c > create mode 100755 tools/testing/selftests/damon/sysfs.sh >
Hi Xin, On Fri, 25 Feb 2022 15:21:05 +0800 xhao@linux.alibaba.com wrote: > Hi, SeongJae: > > On 2/23/22 11:20 PM, SeongJae Park wrote: > > DAMON's debugfs-based user interface served very well, so far. However, > > it unnecessarily depends on debugfs, while DAMON is not aimed to be used > > for only debugging. Also, the interface receives multiple values via > > one file. For example, schemes file receives 18 values separated by > > white spaces. As a result, it is ineffient, hard to be used, and > > difficult to be extended. Especially, keeping backward compatibility of > > user space tools is getting only challenging. It would be better to > > implement another reliable and flexible interface and deprecate the > > debugfs interface in long term. > > > > To this end, this commit implements a stub of a part of the new user > > interface of DAMON using sysfs. Specifically, this commit implements > > the sysfs control parts for virtual address space monitoring. > > > > More specifically, the idea of the new interface is, using directory > > hierarchies and making one file for one value. The hierarchy that this > > commit is introducing is as below. In the below figure, > > parents-children relations are represented with indentations, each > > directory is having ``/`` suffix, and files in each directory are > > separated by comma (","). > > > > /sys/kernel/mm/damon/admin > > │ kdamonds/nr > > │ │ 0/state,pid > > │ │ │ contexts/nr > > │ │ │ │ 0/operations > > │ │ │ │ │ monitoring_attrs/ > > │ │ │ │ │ │ intervals/sample_us,aggr_us,update_us > > │ │ │ │ │ │ nr_regions/min,max > > │ │ │ │ │ targets/nr > > │ │ │ │ │ │ 0/pid > > │ │ │ │ │ │ ... > > │ │ │ │ ... > > │ │ ... > > > > > Writing a number <N> to each 'nr' file makes directories of name <0> to > > <N-1> in the directory of the 'nr' file. That's all this commit does. > > Writing proper values to relevant files will construct the DAMON > > contexts, and writing a special keyword, 'on', to 'state' files for each > > kdamond will ask DAMON to start the constructed contexts. > > > > For a short example, using below commands for > > monitoring virtual address spaces of a given workload is imaginable: > > > > # cd /sys/kernel/mm/damon/admin/ > > # echo 1 > kdamonds/nr > > # echo 1 > kdamonds/0/contexts/nr > > # echo vaddr > kdamonds/0/contexts/0/damon_type > > # echo 1 > kdamonds/0/contexts/0/targets/nr > > # echo $(pidof <workload>) > kdamonds/0/contexts/0/targets/0/pid > > # echo on > kdamonds/0/state > > I do some test about the sys interface, like this: > > [root@rt2k03395 0]# tree > . > ├── contexts > │ ├── 0 > │ │ ├── monitoring_attrs > │ │ │ ├── intervals > │ │ │ │ ├── aggr_us > │ │ │ │ ├── sample_us > │ │ │ │ └── update_us > │ │ │ └── nr_regions > │ │ │ ├── max > │ │ │ └── min > │ │ ├── operations > │ │ ├── schemes > │ │ │ └── nr > │ │ └── targets > │ │ ├── 0 > │ │ │ ├── pid > │ │ │ └── regions > │ │ │ ├── 0 > │ │ │ │ ├── end > │ │ │ │ └── start > │ │ │ ├── 1 > │ │ │ │ ├── end > │ │ │ │ └── start > │ │ │ ├── 10 > │ │ │ │ ├── end > │ │ │ │ └── start > │ │ │ ├── 11 > │ │ │ │ ├── end > │ │ │ │ └── start > │ │ │ ├── 12 > > cd regions/ > [root@rt2k03395 regions]# ls > 0 10 12 14 16 18 2 21 23 25 27 29 30 32 34 36 38 4 > 41 43 45 47 49 6 8 nr > 1 11 13 15 17 19 20 22 24 26 28 3 31 33 35 37 39 40 > 42 44 46 48 5 7 9 > [root@rt2k03395 regions]# cd 44/cat * > > [root@rt2k03395 regions/44]# cat * > 0 0 > > I'm skeptical about the number regions ? And after manually setting the > number of nr, the processing of > > "start" and "end" will be very troublesome,I guess you might want to do > some special region addresses, > > such as hot or cold region, Is that true ？ The purpose of regions/ directory is for supporting the initial monitoring regions feature of debugfs, which is optional for virtual address spaces monitoring, but essential for physical address space monitoing. If you need to monitor only virtual address spaces, you don't need to populate the directory. In a future, we could add nr_accesses and age files under each region directory and apply the monitoring results there. > But I think you need to think > about how do you deal with too many > > uncontacted reigons that need to be done. Sysfs interface is not aimed to be used by human hand but user space tools, and we provide a reference tool, damo. Please consider using that or implement your own. You could also refer to my reply to your other email for this point: https://lore.kernel.org/linux-mm/20220225080513.1908-1-sj@kernel.org/ Thanks, SJ [...]
Chages from Previous Version (RFC) ================================== Compared to the RFC version of this patchset (https://lore.kernel.org/linux-mm/20220217161938.8874-1-sj@kernel.org/), this version contains below changes. - Implement all DAMON debugfs interface providing features - Writeup documents - Add more selftests Introduction ============ DAMON's debugfs-based user interface (DAMON_DBGFS) served very well, so far. However, it unnecessarily depends on debugfs, while DAMON is not aimed to be used for only debugging. Also, the interface receives multiple values via one file. For example, schemes file receives 18 values. As a result, it is inefficient, hard to be used, and difficult to be extended. Especially, keeping backward compatibility of user space tools is getting only challenging. It would be better to implement another reliable and flexible interface and deprecate DAMON_DBGFS in long term. For the reason, this patchset introduces a sysfs-based new user interface of DAMON. The idea of the new interface is, using directory hierarchies and having one dedicated file for each value. For a short example, users can do the virtual address monitoring via the interface as below: # cd /sys/kernel/mm/damon/admin/ # echo 1 > kdamonds/nr # echo 1 > kdamonds/0/contexts/nr # echo vaddr > kdamonds/0/contexts/0/operations # echo 1 > kdamonds/0/contexts/0/targets/nr # echo $(pidof <workload>) > kdamonds/0/contexts/0/targets/0/pid # echo on > kdamonds/0/state A brief representation of the files hierarchy of DAMON sysfs interface is as below. Childs are represented with indentation, directories are having '/' suffix, and files in each directory are separated by comma. /sys/kernel/mm/damon/admin │ kdamonds/nr │ │ 0/state,pid │ │ │ contexts/nr │ │ │ │ 0/operations │ │ │ │ │ monitoring_attrs/ │ │ │ │ │ │ intervals/sample_us,aggr_us,update_us │ │ │ │ │ │ nr_regions/min,max │ │ │ │ │ targets/nr │ │ │ │ │ │ 0/pid │ │ │ │ │ │ │ regions/nr │ │ │ │ │ │ │ │ 0/start,end │ │ │ │ │ │ │ │ ... │ │ │ │ │ │ ... │ │ │ │ │ schemes/nr │ │ │ │ │ 0/action │ │ │ │ │ │ access_pattern/ │ │ │ │ │ │ │ sz/min,max │ │ │ │ │ │ │ nr_accesses/min,max │ │ │ │ │ │ │ age/min,max │ │ │ │ │ │ quotas/ms,sz,reset_interval_ms │ │ │ │ │ │ │ weights/sz,nr_accesses,age │ │ │ │ │ │ watermarks/metric,interval_us,high,mid,low │ │ │ │ │ │ stats/nr_tried,sz_tried,nr_applied,sz_applied,qt_exceeds │ │ │ │ │ ... │ │ ... Detailed usage of the files will be described in the final Documentation patch of this patchset. Main Difference Between DAMON_DBGFS and DAMON_SYSFS --------------------------------------------------- At the moment, DAMON_DBGFS and DAMON_SYSFS provides same features. One important difference between them is their exclusiveness. DAMON_DBGFS works in an exclusive manner, so that no DAMON worker thread (kdamond) in the system can run concurrently and interfere somehow. For the reason, DAMON_DBGFS asks users to construct all monitoring contexts and start them at once. It's not a big problem but makes the operation a little bit complex and unflexible. For more flexible usage, DAMON_SYSFS moves the responsibility of preventing any possible interference to the admins and work in a non-exclusive manner. That is, users can configure and start contexts one by one. Note that DAMON respects both exclusive groups and non-exclusive groups of contexts, in a manner similar to that of reader-writer locks. That is, if any exclusive monitoring contexts (e.g., contexts that started via DAMON_DBGFS) are running, DAMON_SYSFS does not start new contexts, and vice versa. Future Plan of DAMON_DBGFS Deprecation ====================================== Once this patchset is merged, DAMON_DBGFS development will be frozen. That is, we will maintain it to work as is now so that no users will be break. But, it will not be extended to provide any new feature of DAMON. The support will be continued only until next LTS release. After that, we will drop DAMON_DBGFS. User-space Tooling Compatibility -------------------------------- As DAMON_SYSFS provides all features of DAMON_DBGFS, all user space tooling can move to DAMON_SYSFS. As we will continue supporting DAMON_DBGFS until next LTS kernel release, user space tools would have enough time to move to DAMON_SYSFS. The official user space tool, damo[1], is already supporting both DAMON_SYSFS and DAMON_DBGFS. Both correctness tests[2] and performance tests[3] of DAMON using DAMON_SYSFS also passed. [1] https://github.com/awslabs/damo [2] https://github.com/awslabs/damon-tests/tree/master/corr [3] https://github.com/awslabs/damon-tests/tree/master/perf Complete Git Tree ================= You can get the complete git tree from https://git.kernel.org/sj/h/damon/sysfs/patches/v1. Sequence of Patches =================== First two patches (patches 1-2) make core changes for DAMON_SYSFS. The first one (patch 1) allows non-exclusive DAMON contexts so that DAMON_SYSFS can work in non-exclusive mode, while the second one (patch 2) adds size of DAMON enum types so that DAMON API users can safely iterate the enums. Third patch (patch 3) implements basic sysfs stub for virtual address spaces monitoring. Note that this implements only sysfs files and DAMON is not linked. Fourth patch (patch 4) links the DAMON_SYSFS to DAMON so that users can control DAMON using the sysfs files. Following six patches (patches 5-10) implements other DAMON features that DAMON_DBGFS supports one by one (physical address space monitoring, DAMON-based operation schemes, schemes quotas, schemes prioritization weights, schemes watermarks, and schemes stats). Following patch (patch 11) adds a simple selftest for DAMON_SYSFS, and the final one (patch 12) documents DAMON_SYSFS. SeongJae Park (12): mm/damon/core: Allow non-exclusive DAMON start/stop mm/damon/core: Add number of each enum type values mm/damon: Implement a minimal stub for sysfs-based DAMON interface mm/damon/sysfs: Link DAMON for virtual address spaces monitoring mm/damon/sysfs: Support physical address space monitoring mm/damon/sysfs: Support DAMON-based Operation Schemes mm/damon/sysfs: Support DAMOS quotas mm/damon/sysfs: Support schemes prioritization weights mm/damon/sysfs: Support DAMOS watermarks mm/damon/sysfs: Support DAMOS stats selftests/damon: Add a test for DAMON sysfs interface Docs/admin-guide/mm/damon/usage: Document DAMON sysfs interface Documentation/admin-guide/mm/damon/usage.rst | 349 ++- include/linux/damon.h | 6 +- mm/damon/Kconfig | 7 + mm/damon/Makefile | 1 + mm/damon/core.c | 23 +- mm/damon/dbgfs.c | 2 +- mm/damon/reclaim.c | 2 +- mm/damon/sysfs.c | 2684 ++++++++++++++++++ tools/testing/selftests/damon/Makefile | 1 + tools/testing/selftests/damon/sysfs.sh | 306 ++ 10 files changed, 3364 insertions(+), 17 deletions(-) create mode 100644 mm/damon/sysfs.c create mode 100755 tools/testing/selftests/damon/sysfs.sh