Re: [RFC/PATCH] Add sysfs control to modify a user's cpu share
On Tue, Oct 02, 2007 at 06:12:39PM -0400, Eric St-Laurent wrote: > While a sysfs interface is OK and somewhat orthogonal to the interface > proposed the containers patches, I think maybe a new syscall should be > considered. We had discussed syscall vs filesystem based interface for resource management [1] and there was a heavy bias favoring filesystem based interface, based on which the container (now "cgroup") filesystem evolved. Where we already have one interface defined, I would be against adding an equivalent syscall interface. Note that this "fair-user" scheduling can in theory be accomplished using the same cgroup based interface, but requires some extra setup in userspace (either to run a daemon which moves tasks to appropriate control groups/containers upon their uid change OR to modify initrd to mount cgroup filesystem at early bootup time). I expect most distros to enable CONFIG_FAIR_CGROUP_SCHED (control group based fair group scheduler) and not CONFIG_FAIR_USER_SHCED (user id based fair group scheduler). The only reason why we are providing CONFIG_FAIR_USER_SCHED and the associated sysfs interface is to help test group scheduler w/o requiring knowledge of cgroup filesystem. Reference: 1. http://marc.info/?l=linux-kernel&m=116231242201300&w=2 -- Regards, vatsa - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [RFC/PATCH] Add sysfs control to modify a user's cpu share
On Mon, 2007-10-01 at 16:44 +0200, Ingo Molnar wrote: > > Adds tunables in sysfs to modify a user's cpu share. > > > > A directory is created in sysfs for each new user in the system. > > > > /sys/kernel/uids//cpu_share > > > > Reading this file returns the cpu shares granted for the user. > > Writing into this file modifies the cpu share for the user. Only an > > administrator is allowed to modify a user's cpu share. > > > > Ex: > > # cd /sys/kernel/uids/ > > # cat 512/cpu_share > > 1024 > > # echo 2048 > 512/cpu_share > > # cat 512/cpu_share > > 2048 > > # > > looks good to me! I think this API is pretty straightforward. I've put > this into my tree and have updated the sched-devel git tree: > While a sysfs interface is OK and somewhat orthogonal to the interface proposed the containers patches, I think maybe a new syscall should be considered. Since we now have a fair share cpu scheduler, maybe an interface to specify the cpu share directly (alternatively to priority) make sense. For processes, it may become more intuitive (and precise) to set the processing share directly than setting a priority which is converted to a share. Maybe something similar to ioprio_set() and ioprio_get() syscalls: - per user cpu share - per user group cpu share - per process cpu share - per process group cpu share Best regards, - Eric - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [RFC/PATCH] Add sysfs control to modify a user's cpu share
On Mon, Oct 01, 2007 at 12:12:21PM -0400, Dave Jones wrote: > Can we start adding stuff to Documentation/ for new files created > in sysfs ? There's so much undocumented stuff in there now that > it's unfunny. Hi Dave, We will in the next version of the patch. At this point, the patch was sent out to get an idea of whether sysfs is the right place for this interface or not. > A great start would be 'wtf is a cpu_share and why would I want to > change it' ? Quick answer before we release the next version : This has to do with the CONFIG_FAIR_USER_SCHED feature which allows dividing CPU bandwidth equally between all users of a system. Before this patch, CPU bandwidth was divided equally among all non-root users. After this patch, it will be possible to control CPU bandwidth allocation to each user separately. For ex: by setting user "vatsa"'s cpu_share to be twice that of user "guest", it would be possible for user "vatsa" to get 2x CPU bandwidth that of user "guest" -- Regards, vatsa - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [RFC/PATCH] Add sysfs control to modify a user's cpu share
On Mon, Oct 01, 2007 at 07:34:54PM +0530, Dhaval Giani wrote: > Hi Ingo, > > Adds tunables in sysfs to modify a user's cpu share. > > A directory is created in sysfs for each new user in the system. > > /sys/kernel/uids//cpu_share > > Reading this file returns the cpu shares granted for the user. > Writing into this file modifies the cpu share for the user. Only an > administrator is allowed to modify a user's cpu share. > > Ex: > # cd /sys/kernel/uids/ > # cat 512/cpu_share > 1024 > # echo 2048 > 512/cpu_share > # cat 512/cpu_share > 2048 > # Can we start adding stuff to Documentation/ for new files created in sysfs ? There's so much undocumented stuff in there now that it's unfunny. A great start would be 'wtf is a cpu_share and why would I want to change it' ? Dave -- http://www.codemonkey.org.uk - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [RFC/PATCH] Add sysfs control to modify a user's cpu share
On Mon, Oct 01, 2007 at 04:44:02PM +0200, Ingo Molnar wrote: > but there seems to be a bug in it, i get this: > > kobject_add failed for 500 with -EEXIST, don't try to register things with > the same name in the same directory. Looks like a remove_dir/create_dir race .. free_user() alloc_uid() uid_hash_remove(up); uid_hash_insert(new, hashent); schedule_work() user_kobject_create(); kobject_add(); -> Boom! remove_user_sysfs_dir(); /me looks up sysfs programming examples .. -- Regards, vatsa - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [RFC/PATCH] Add sysfs control to modify a user's cpu share
hi Dhaval, * Dhaval Giani <[EMAIL PROTECTED]> wrote: > Hi Ingo, > > Adds tunables in sysfs to modify a user's cpu share. > > A directory is created in sysfs for each new user in the system. > > /sys/kernel/uids//cpu_share > > Reading this file returns the cpu shares granted for the user. > Writing into this file modifies the cpu share for the user. Only an > administrator is allowed to modify a user's cpu share. > > Ex: > # cd /sys/kernel/uids/ > # cat 512/cpu_share > 1024 > # echo 2048 > 512/cpu_share > # cat 512/cpu_share > 2048 > # looks good to me! I think this API is pretty straightforward. I've put this into my tree and have updated the sched-devel git tree: git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-sched-devel.git but there seems to be a bug in it, i get this: kobject_add failed for 500 with -EEXIST, don't try to register things with the same name in the same directory. [] kobject_shadow_add+0x13b/0x169 [] kobject_set_name+0x28/0x91 [] user_kobject_create+0x6a/0x90 [] alloc_uid+0x141/0x181 [] set_user+0x1c/0x91 [] sys_setresuid+0xd9/0x17d [] sysenter_past_esp+0x5f/0x85 === Ingo - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[RFC/PATCH] Add sysfs control to modify a user's cpu share
Hi Ingo,
Adds tunables in sysfs to modify a user's cpu share.
A directory is created in sysfs for each new user in the system.
/sys/kernel/uids//cpu_share
Reading this file returns the cpu shares granted for the user.
Writing into this file modifies the cpu share for the user. Only an
administrator is allowed to modify a user's cpu share.
Ex:
# cd /sys/kernel/uids/
# cat 512/cpu_share
1024
# echo 2048 > 512/cpu_share
# cat 512/cpu_share
2048
#
Signed-off-by: Srivatsa Vaddagiri <[EMAIL PROTECTED]>
Signed-off-by: Dhaval Giani <[EMAIL PROTECTED]>
---
include/linux/sched.h | 11 +
kernel/ksysfs.c |4 +
kernel/sched.c|5 ++
kernel/user.c | 110 +-
4 files changed, 129 insertions(+), 1 deletion(-)
Index: linux-2.6.23-rc8-sched-devel/include/linux/sched.h
===
--- linux-2.6.23-rc8-sched-devel.orig/include/linux/sched.h
+++ linux-2.6.23-rc8-sched-devel/include/linux/sched.h
@@ -86,6 +86,7 @@ struct sched_param {
#include
#include
#include
+#include
#include
@@ -598,9 +599,18 @@ struct user_struct {
#ifdef CONFIG_FAIR_USER_SCHED
struct task_group *tg;
+ struct kset kset;
+ struct subsys_attribute user_attr;
+ struct work_struct work;
#endif
};
+#ifdef CONFIG_FAIR_USER_SCHED
+extern int uids_kobject_init(void);
+#else
+static inline int uids_kobject_init(void) { return 0; }
+#endif
+
extern struct user_struct *find_user(uid_t);
extern struct user_struct root_user;
@@ -1846,6 +1856,7 @@ extern struct task_group *sched_create_g
extern void sched_destroy_group(struct task_group *tg);
extern void sched_move_task(struct task_struct *tsk);
extern int sched_group_set_shares(struct task_group *tg, unsigned long shares);
+extern unsigned long sched_group_shares(struct task_group *tg);
#endif
Index: linux-2.6.23-rc8-sched-devel/kernel/ksysfs.c
===
--- linux-2.6.23-rc8-sched-devel.orig/kernel/ksysfs.c
+++ linux-2.6.23-rc8-sched-devel/kernel/ksysfs.c
@@ -14,6 +14,7 @@
#include
#include
#include
+#include
#define KERNEL_ATTR_RO(_name) \
static struct subsys_attribute _name##_attr = __ATTR_RO(_name)
@@ -116,6 +117,9 @@ static int __init ksysfs_init(void)
¬es_attr);
}
+ if (!error)
+ error = uids_kobject_init();
+
return error;
}
Index: linux-2.6.23-rc8-sched-devel/kernel/sched.c
===
--- linux-2.6.23-rc8-sched-devel.orig/kernel/sched.c
+++ linux-2.6.23-rc8-sched-devel/kernel/sched.c
@@ -6928,4 +6928,9 @@ int sched_group_set_shares(struct task_g
return 0;
}
+unsigned long sched_group_shares(struct task_group *tg)
+{
+ return tg->shares;
+}
+
#endif /* CONFIG_FAIR_GROUP_SCHED */
Index: linux-2.6.23-rc8-sched-devel/kernel/user.c
===
--- linux-2.6.23-rc8-sched-devel.orig/kernel/user.c
+++ linux-2.6.23-rc8-sched-devel/kernel/user.c
@@ -56,6 +56,62 @@ struct user_struct root_user = {
};
#ifdef CONFIG_FAIR_USER_SCHED
+
+static struct kobject uids_kobject;
+
+ssize_t cpu_shares_show(struct kset *kset, char *buffer)
+{
+ struct user_struct *up = container_of(kset, struct user_struct, kset);
+
+ return sprintf(buffer, "%lu\n", sched_group_shares(up->tg));
+}
+
+ssize_t cpu_shares_store(struct kset *kset, const char *buffer, size_t size)
+{
+ struct user_struct *up = container_of(kset, struct user_struct, kset);
+ unsigned long shares;
+ int rc;
+
+ sscanf(buffer, "%lu", &shares);
+
+ rc = sched_group_set_shares(up->tg, shares);
+
+ return (rc ? rc : size);
+}
+
+static void user_attr_init(struct subsys_attribute *sa, char *name, int mode)
+{
+ sa->attr.name = name;
+ sa->attr.mode = mode;
+ sa->show = cpu_shares_show;
+ sa->store = cpu_shares_store;
+}
+
+static int user_kobject_create(struct user_struct *up)
+{
+ struct kset *kset = &up->kset;
+ struct kobject *kobj = &kset->kobj;
+ int error;
+
+ memset(kset, 0, sizeof(struct kset));
+ kobj->parent = &uids_kobject;
+ kobject_set_name(kobj, "%d", up->uid);
+ kset_init(kset);
+ user_attr_init(&up->user_attr, "cpu_share", 0644);
+
+ error = kobject_add(kobj);
+
+ if (error)
+ goto done;
+
+ error = sysfs_create_file(kobj, &up->user_attr.attr);
+ if (error)
+ kobject_del(kobj);
+
+done:
+ return error;
+}
+
static void sched_destroy_user(struct user_struct *up)
{
sched_destroy_group(up->tg);
@@ -77,11 +133,53 @@ static void sched_switch_user(struct tas
sched_move_task(p);
}
+int __init uids_kobject_init(void)
+{
+
