posix timers: Extend kernel API to report more info about timers (v3)
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cover posix timers: Extend kernel API to report more info about timers (v3)
Hi.
Currently kernel doesn't provide any API for getting information about what timers are currently created by process and in which state they are. Also, the way timer IDs are generated makes it impossible to create a timer with any desired ID. Both facilities are very very tempting by the checkpoint-restore project.
That said, this series fixes posix timers API in this way:
1. it makes timers IDs generation per-signal_struct to allow for recreation of a timer with desired ID;
2. it adds per-task proc file where all timers created by it are listed.
This v3 series is ported on v3.9-rc2 and patches' changelogs are fixed according to Thomas' feedback to contain info why the change is required.
Thanks,
Pavel
PATCH 1/3 posix timers: Allocate timer id per process (v2)
Currently kernel generates IDs for posix timers in a global manner -- there's a kernel-wide IDR tree from which IDs are created. This makes it impossible to recreate a timer with a desired ID (in particulat this is done by the CRIU checkpoint-restore project) -- since these IDs are global it may happen, that at the time we recreate a timer, the ID we want for it is already busy by some other timer.
In order to address this, I'd like to replace the mentioned IDR tree with global hash table for timers and makes timer IDs unique per signal_struct (to which timers are linked anyway). With this, two timers belonging to different tasks may have equal IDs and we can recreate either of them with ID we want.
--- include/linux/posix-timers.h | 1 + include/linux/sched.h | 3 +- kernel/posix-timers.c | 106 +++++++++++++++++++++++++++--------------- 3 files changed, 72 insertions(+), 38 deletions(-)
include/linux/posix-timers.h +1 -0
@@ -55,6 +55,7 @@ struct cpu_timer_list {/* POSIX.1b interval timer structure. */ struct k_itimer {struct list_head list;/* free/ allocate list */ +struct hlist_node t_hash;spinlock_t it_lock;clockid_t it_clock;/* which timer type */ timer_t it_id;/* timer id */
include/linux/sched.h +2 -1
@@ -526,7 +526,8 @@ struct signal_struct { unsigned int has_child_subreaper:1;/* POSIX.1b Interval Timers */ -struct list_head posix_timers; +int posix_timer_id; +struct list_head posix_timers;/* ITIMER_REAL timer for the process */ struct hrtimer real_timer;
kernel/posix-timers.c +69 -37
158 lines not on this page · raw message
Signature · 1 line
1.7.6.5
tip-bot for Pavel Emelyanov
merge bot[tip:timers/core] posix timers: Allocate timer id per process (v2 )
posix timers: Allocate timer id per process (v2)
Commit-ID: 5ed67f05f66c41e39880a6d61358438a25f9fee5 Gitweb: http://git.kernel.org/tip/5ed67f05f66c41e39880a6d61358438a25f9fee5 Author: Pavel Emelyanov <[email protected]> AuthorDate: Mon, 11 Mar 2013 13:12:21 +0400 Committer: Thomas Gleixner <[email protected]> CommitDate: Wed, 17 Apr 2013 20:51:01 +0200
posix timers: Allocate timer id per process (v2)
Currently kernel generates IDs for posix timers in a global manner -- there's a kernel-wide IDR tree from which IDs are created. This makes it impossible to recreate a timer with a desired ID (in particular this is done by the CRIU checkpoint-restore project) -- since these IDs are global it may happen, that at the time we recreate a timer, the ID we want for it is already busy by some other timer.
In order to address this, replace the IDR tree with a global hash table for timers and makes timer IDs unique per signal_struct (to which timers are linked anyway). With this, two timers belonging to different processes may have equal IDs and we can recreate either of them with the ID we want.
--- include/linux/posix-timers.h | 1 + include/linux/sched.h | 3 +- kernel/posix-timers.c | 106 ++++++++++++++++++++++++++++--------------- 3 files changed, 72 insertions(+), 38 deletions(-)
include/linux/posix-timers.h +1 -0
@@ -55,6 +55,7 @@ struct cpu_timer_list {/* POSIX.1b interval timer structure. */ struct k_itimer {struct list_head list;/* free/ allocate list */ +struct hlist_node t_hash;spinlock_t it_lock;clockid_t it_clock;/* which timer type */ timer_t it_id;/* timer id */
include/linux/sched.h +2 -1
@@ -526,7 +526,8 @@ struct signal_struct { unsigned int has_child_subreaper:1;/* POSIX.1b Interval Timers */ -struct list_head posix_timers; +int posix_timer_id; +struct list_head posix_timers;/* ITIMER_REAL timer for the process */ struct hrtimer real_timer;
kernel/posix-timers.c +69 -37
158 lines not on this page · raw message
PATCH 2/3 posix-timers: Introduce /proc/<pid>/timers file
In reply to Pavel EmelyanovCurrently kernel doesn't provide any API for getting info about what posix timers are configured by tasks. It's implied, that task, that configured some timers, knows what it did. However, for external tools it's impossible to get this information. In particular, this is critical for checkpoint-restore project to have this info.
That said, the proposal is to introduce the per-pid proc file with information about posix timers. Since these timers are shared between threads, this file is present on tgid level only, no such thing in tid subdirs.
The file format is expected to be the "/proc/<pid>/smaps"-like, i.e. each timer will occupy seveal lines to allow for future extending.
Each new timer entry starts with the
ID: <number>
line which is added by this patch.
--- fs/proc/base.c | 83 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 83 insertions(+), 0 deletions(-)
fs/proc/base.c +83 -0
@@ -86,6 +86,7 @@#include <linux/fs_struct.h> #include <linux/slab.h> #include <linux/flex_array.h> +#include <linux/posix-timers.h> #ifdef CONFIG_HARDWALL #include <asm/hardwall.h> #endif
@@ -2013,6 +2014,85 @@ static const struct file_operations proc_map_files_operations = { .llseek = default_llseek, }; +struct timers_private { +struct pid *pid; +struct task_struct *task; +struct sighand_struct *sighand; +unsigned long flags; +}; + +static void *timers_start (struct seq_file *m,loff_t *pos) +{ +struct timers_private *tp = m->private; + + tp->task =get_pid_task (tp->pid,PIDTYPE_PID ); +if (!tp->task) +return ERR_PTR (-ESRCH ); + + tp->sighand =lock_task_sighand (tp->task, &tp->flags); +if (!tp->sighand) +return ERR_PTR (-ESRCH ); + +return seq_list_start (&tp->task->signal->posix_timers, *pos); +} + +static void *timers_next (struct seq_file *m,void *v,loff_t *pos) +{ +struct timers_private *tp = m->private; +return seq_list_next (v, &tp->task->signal->posix_timers, pos); +} + +static void timers_stop (struct seq_file *m,void *v) +{ +struct timers_private *tp = m->private; + +if (tp->sighand) { +unlock_task_sighand (tp->task, &tp->flags); + tp->sighand =NULL ; + } + +if (tp->task) { +put_task_struct (tp->task); + tp->task =NULL ; + } +} + +static int show_timer (struct seq_file *m,void *v) +{ +struct k_itimer *timer; + + timer = list_entry((struct list_head *)v, struct k_itimer, list); +seq_printf (m,"ID: %d\n" , timer->it_id); + +return 0 ; +} + +static const struct seq_operations proc_timers_seq_ops = { + .start = timers_start, + .next = timers_next, + .stop = timers_stop, + .show = show_timer, +}; + +static int proc_timers_open (struct inode *inode,struct file *file) +{ +struct timers_private *tp; + + tp =__seq_open_private (file, &proc_timers_seq_ops, +sizeof (struct timers_private )); +if (!tp) +return -ENOMEM ; + + tp->pid =proc_pid (inode); +return 0 ; +} + +static const struct file_operations proc_timers_operations = { + .open = proc_timers_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release_private, +};#endif /* CONFIG_CHECKPOINT_RESTORE */ static struct dentry *proc_pident_instantiate(struct inode *dir,
@@ -2583,6 +2663,9 @@ static const struct pid_entry tgid_base_stuff[] = { REG("gid_map", S_IRUGO|S_IWUSR, proc_gid_map_operations), REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),#endif +#ifdef CONFIG_CHECKPOINT_RESTORE + REG("timers", S_IRUGO, proc_timers_operations), +#endif }; static int proc_tgid_base_readdir(struct file * filp,
Signature · 1 line
1.7.6.5
tip-bot for Pavel Emelyanov
merge bot[tip:timers/core] posix-timers: Introduce /proc/PID/timers file
posix-timers: Introduce /proc/PID/timers file
Commit-ID: 48f6a7a511ef8823fdff39afee0320092d43a8a0 Gitweb: http://git.kernel.org/tip/48f6a7a511ef8823fdff39afee0320092d43a8a0 Author: Pavel Emelyanov <[email protected]> AuthorDate: Mon, 11 Mar 2013 13:12:45 +0400 Committer: Thomas Gleixner <[email protected]> CommitDate: Wed, 17 Apr 2013 20:51:01 +0200
posix-timers: Introduce /proc/PID/timers file
Currently kernel doesn't provide any API for getting info about what posix timers are configured by processes. It's implied, that a process which configured some timers, knows what it did. However, for external tools it's impossible to get this information. In particular, this is critical for checkpoint-restore project to have this info.
Introduce a per-pid proc file with information about posix timers. Since these timers are shared between threads, this file is present on tgid level only, no such thing in tid subdirs.
The file format is expected to be the "/proc/<pid>/smaps"-like, i.e. each timer will occupy seveal lines to allow for future extending.
Each new timer entry starts with the
ID: <number>
line which is added by this patch.
--- fs/proc/base.c | 83 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 83 insertions(+)
fs/proc/base.c +83 -0
@@ -86,6 +86,7 @@#include <linux/fs_struct.h> #include <linux/slab.h> #include <linux/flex_array.h> +#include <linux/posix-timers.h> #ifdef CONFIG_HARDWALL #include <asm/hardwall.h> #endif
@@ -2013,6 +2014,85 @@ static const struct file_operations proc_map_files_operations = { .llseek = default_llseek, }; +struct timers_private { +struct pid *pid; +struct task_struct *task; +struct sighand_struct *sighand; +unsigned long flags; +}; + +static void *timers_start (struct seq_file *m,loff_t *pos) +{ +struct timers_private *tp = m->private; + + tp->task =get_pid_task (tp->pid,PIDTYPE_PID ); +if (!tp->task) +return ERR_PTR (-ESRCH ); + + tp->sighand =lock_task_sighand (tp->task, &tp->flags); +if (!tp->sighand) +return ERR_PTR (-ESRCH ); + +return seq_list_start (&tp->task->signal->posix_timers, *pos); +} + +static void *timers_next (struct seq_file *m,void *v,loff_t *pos) +{ +struct timers_private *tp = m->private; +return seq_list_next (v, &tp->task->signal->posix_timers, pos); +} + +static void timers_stop (struct seq_file *m,void *v) +{ +struct timers_private *tp = m->private; + +if (tp->sighand) { +unlock_task_sighand (tp->task, &tp->flags); + tp->sighand =NULL ; + } + +if (tp->task) { +put_task_struct (tp->task); + tp->task =NULL ; + } +} + +static int show_timer (struct seq_file *m,void *v) +{ +struct k_itimer *timer; + + timer = list_entry((struct list_head *)v, struct k_itimer, list); +seq_printf (m,"ID: %d\n" , timer->it_id); + +return 0 ; +} + +static const struct seq_operations proc_timers_seq_ops = { + .start = timers_start, + .next = timers_next, + .stop = timers_stop, + .show = show_timer, +}; + +static int proc_timers_open (struct inode *inode,struct file *file) +{ +struct timers_private *tp; + + tp =__seq_open_private (file, &proc_timers_seq_ops, +sizeof (struct timers_private )); +if (!tp) +return -ENOMEM ; + + tp->pid =proc_pid (inode); +return 0 ; +} + +static const struct file_operations proc_timers_operations = { + .open = proc_timers_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release_private, +};#endif /* CONFIG_CHECKPOINT_RESTORE */ static struct dentry *proc_pident_instantiate(struct inode *dir,
@@ -2583,6 +2663,9 @@ static const struct pid_entry tgid_base_stuff[] = { REG("gid_map", S_IRUGO|S_IWUSR, proc_gid_map_operations), REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),#endif +#ifdef CONFIG_CHECKPOINT_RESTORE + REG("timers", S_IRUGO, proc_timers_operations), +#endif }; static int proc_tgid_base_readdir(struct file * filp,
PATCH 3/3 posix-timers: Show sigevent info in proc file
In reply to Pavel EmelyanovPrevious patch added proc file to list posix timers created by task. Expand the information provided in this file by adding info about notification method, with which timers were created. I.e. after the "ID:" line there go
1. "signal:" line, that shows signal number and sigval bits;
2. "notify:" line, that shows the timer notification method.
Thus the timer entry would looke like this:
ID: 123
signal: 14/0000000000b005d0
notify: signal/pid.732
This information is enough to understand how the timer_create() was called for each particular timer.
--- fs/proc/base.c | 17 +++++++++++++++++ 1 files changed, 17 insertions(+), 0 deletions(-)
fs/proc/base.c +17 -0
@@ -2018,6 +2018,7 @@ struct timers_private {struct pid *pid;struct task_struct *task;struct sighand_struct *sighand; +struct pid_namespace *ns;unsigned long flags; };
@@ -2060,9 +2061,24 @@ static void timers_stop(struct seq_file *m, void *v)static int show_timer (struct seq_file *m,void *v) {struct k_itimer *timer; +struct timers_private *tp = m->private; +int notify; +static char *nstr[] = { + [SIGEV_SIGNAL ] ="signal" , + [SIGEV_NONE ] ="none" , + [SIGEV_THREAD ] ="thread" , + }; timer = list_entry((struct list_head *)v, struct k_itimer, list); + notify = timer->it_sigev_notify; +seq_printf (m,"ID: %d\n" , timer->it_id); +seq_printf (m,"signal: %d/%p\n" , timer->sigq->info.si_signo, + timer->sigq->info.si_value.sival_ptr); +seq_printf (m,"notify: %s/%s.%d\n" , + nstr[notify & ~SIGEV_THREAD_ID ], + (notify &SIGEV_THREAD_ID ) ?"tid" :"pid" , +pid_nr_ns (timer->it_pid, tp->ns));return 0 ; }
@@ -2084,6 +2100,7 @@ static int proc_timers_open(struct inode *inode, struct file *file)return -ENOMEM ; tp->pid =proc_pid (inode); + tp->ns = inode->i_sb->s_fs_info;return 0 ; }
Signature · 1 line
1.7.6.5
tip-bot for Pavel Emelyanov
merge bot[tip:timers/core] posix-timers: Show sigevent info in proc file
posix-timers: Show sigevent info in proc file
Commit-ID: 57b8015e07a70301e9ec9f324db1a8b73b5a1e2b Gitweb: http://git.kernel.org/tip/57b8015e07a70301e9ec9f324db1a8b73b5a1e2b Author: Pavel Emelyanov <[email protected]> AuthorDate: Mon, 11 Mar 2013 13:13:08 +0400 Committer: Thomas Gleixner <[email protected]> CommitDate: Wed, 17 Apr 2013 20:51:01 +0200
posix-timers: Show sigevent info in proc file
Previous patch added proc file to list posix timers created by task. Expand the information provided in this file by adding info about notification method, with which timers were created. I.e. after the "ID:" line there go
1. "signal:" line, that shows signal number and sigval bits;
2. "notify:" line, that shows the timer notification method.
Thus the timer entry would looke like this:
ID: 123
signal: 14/0000000000b005d0
notify: signal/pid.732
This information is enough to understand how timer_create() was called for each particular timer.
--- fs/proc/base.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)
fs/proc/base.c +17 -0
@@ -2018,6 +2018,7 @@ struct timers_private {struct pid *pid;struct task_struct *task;struct sighand_struct *sighand; +struct pid_namespace *ns;unsigned long flags; };
@@ -2060,9 +2061,24 @@ static void timers_stop(struct seq_file *m, void *v)static int show_timer (struct seq_file *m,void *v) {struct k_itimer *timer; +struct timers_private *tp = m->private; +int notify; +static char *nstr[] = { + [SIGEV_SIGNAL ] ="signal" , + [SIGEV_NONE ] ="none" , + [SIGEV_THREAD ] ="thread" , + }; timer = list_entry((struct list_head *)v, struct k_itimer, list); + notify = timer->it_sigev_notify; +seq_printf (m,"ID: %d\n" , timer->it_id); +seq_printf (m,"signal: %d/%p\n" , timer->sigq->info.si_signo, + timer->sigq->info.si_value.sival_ptr); +seq_printf (m,"notify: %s/%s.%d\n" , + nstr[notify & ~SIGEV_THREAD_ID ], + (notify &SIGEV_THREAD_ID ) ?"tid" :"pid" , +pid_nr_ns (timer->it_pid, tp->ns));return 0 ; }
@@ -2084,6 +2100,7 @@ static int proc_timers_open(struct inode *inode, struct file *file)return -ENOMEM ; tp->pid =proc_pid (inode); + tp->ns = inode->i_sb->s_fs_info;return 0 ; }
Quoted 10 lines · Pavel Emelyanov
Hi.
Currently kernel doesn't provide any API for getting information about what timers are currently created by process and in which state they are. Also, the way timer IDs are generated makes it impossible to create a timer with any desired ID. Both facilities are very very tempting by the checkpoint-restore project.
That said, this series fixes posix timers API in this way:
Quoted 7 lines
1. it makes timers IDs generation per-signal_struct to allow for recreation of a timer with desired ID;
2. it adds per-task proc file where all timers created by it are listed.This v3 series is ported on v3.9-rc2 and patches' changelogs are fixed according to Thomas' feedback to contain info why the change is required.
Gentlemen,
I'm sorry for bothering you again, but I've (hopefully) addressed the issues Thomas pointed out with the previous version of this set, thus I would like to ask you about your plans about it. If there's anything else I should do, just let me know.
Thanks,
Pavel
Quoted 6 lines · Pavel Emelyanov
Quoted 4 lines · Pavel Emelyanov
Hi.
This v3 series is ported on v3.9-rc2 and patches' changelogs are fixed according to Thomas' feedback to contain info why the change is required.
Quoted 6 lines
Gentlemen,
I'm sorry for bothering you again, but I've (hopefully) addressed the issues Thomas pointed out with the previous version of this set, thus I would like to ask you about your plans about it. If there's anything else I should do, just let me know.
Dear Sirs,
Any feedback on this set will be highly appreciated.
Yours sincerely,
Pavel