GitHub-Mirror/linux-bl808
2
0
Fork 0
mirror of https://github.com/Fishwaldo/linux-bl808.git synced 2025-06-17 20:25:19 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

[PATCH] s390: deadlock in appldata

Browse source 
The system might hang when using appldata_mem with high I/O traffic and a
large number of devices.  The spinlocks bdev_lock and swaplock are acquired
via calls to si_meminfo() and si_swapinfo() from a tasklet, i.e.  interrupt
context, which can lead to a deadlock.  Replace tasklet with work queue.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Gerald Schaefer 2005-06-04 15:43:33 -07:00 • committed by Linus Torvalds
parent 595bf2aaca
commit f26d583e41
4 changed files with 45 additions and 35 deletions
Download patch file Download diff file Expand all files Collapse all files

72
arch/s390/appldata/appldata_base.c
View file

@ -28,6 +28,7 @@
//#include <linux/kernel_stat.h> //#include <linux/kernel_stat.h>
#include <linux/notifier.h> #include <linux/notifier.h>
#include <linux/cpu.h> #include <linux/cpu.h>
#include <linux/workqueue.h>
#include "appldata.h" #include "appldata.h"
@ -133,9 +134,12 @@ static int appldata_interval = APPLDATA_CPU_INTERVAL;
static int appldata_timer_active; static int appldata_timer_active;
/* /*
* Tasklet * Work queue
*/ */
static struct tasklet_struct appldata_tasklet_struct; static struct workqueue_struct *appldata_wq;
static void appldata_work_fn(void *data);
static DECLARE_WORK(appldata_work, appldata_work_fn, NULL);
/* /*
* Ops list * Ops list
@ -144,11 +148,11 @@ static DEFINE_SPINLOCK(appldata_ops_lock);
static LIST_HEAD(appldata_ops_list); static LIST_HEAD(appldata_ops_list);
/************************* timer, tasklet, DIAG ******************************/ /*************************** timer, work, DIAG *******************************/
/* /*
* appldata_timer_function() * appldata_timer_function()
* *
* schedule tasklet and reschedule timer * schedule work and reschedule timer
*/ */
static void appldata_timer_function(unsigned long data, struct pt_regs *regs) static void appldata_timer_function(unsigned long data, struct pt_regs *regs)
{ {
@ -157,22 +161,22 @@ static void appldata_timer_function(unsigned long data, struct pt_regs *regs)
atomic_read(&appldata_expire_count)); atomic_read(&appldata_expire_count));
if (atomic_dec_and_test(&appldata_expire_count)) { if (atomic_dec_and_test(&appldata_expire_count)) {
atomic_set(&appldata_expire_count, num_online_cpus()); atomic_set(&appldata_expire_count, num_online_cpus());
tasklet_schedule((struct tasklet_struct *) data); queue_work(appldata_wq, (struct work_struct *) data);
} }
} }
/* /*
* appldata_tasklet_function() * appldata_work_fn()
* *
* call data gathering function for each (active) module * call data gathering function for each (active) module
*/ */
static void appldata_tasklet_function(unsigned long data) static void appldata_work_fn(void *data)
{ {
struct list_head *lh; struct list_head *lh;
struct appldata_ops *ops; struct appldata_ops *ops;
int i; int i;
P_DEBUG(" -= Tasklet =-\n"); P_DEBUG(" -= Work Queue =-\n");
i = 0; i = 0;
spin_lock(&appldata_ops_lock); spin_lock(&appldata_ops_lock);
list_for_each(lh, &appldata_ops_list) { list_for_each(lh, &appldata_ops_list) {
@ -231,7 +235,7 @@ static int appldata_diag(char record_nr, u16 function, unsigned long buffer,
: "=d" (ry) : "d" (&(appldata_parameter_list)) : "cc"); : "=d" (ry) : "d" (&(appldata_parameter_list)) : "cc");
return (int) ry; return (int) ry;
} }
/********************** timer, tasklet, DIAG <END> ***************************/ /************************ timer, work, DIAG <END> ****************************/
/****************************** /proc stuff **********************************/ /****************************** /proc stuff **********************************/
@ -411,7 +415,7 @@ appldata_generic_handler(ctl_table *ctl, int write, struct file *filp,
struct list_head *lh; struct list_head *lh;
found = 0; found = 0;
spin_lock_bh(&appldata_ops_lock); spin_lock(&appldata_ops_lock);
list_for_each(lh, &appldata_ops_list) { list_for_each(lh, &appldata_ops_list) {
tmp_ops = list_entry(lh, struct appldata_ops, list); tmp_ops = list_entry(lh, struct appldata_ops, list);
if (&tmp_ops->ctl_table[2] == ctl) { if (&tmp_ops->ctl_table[2] == ctl) {
@ -419,15 +423,15 @@ appldata_generic_handler(ctl_table *ctl, int write, struct file *filp,
} }
} }
if (!found) { if (!found) {
spin_unlock_bh(&appldata_ops_lock); spin_unlock(&appldata_ops_lock);
return -ENODEV; return -ENODEV;
} }
ops = ctl->data; ops = ctl->data;
if (!try_module_get(ops->owner)) { // protect this function if (!try_module_get(ops->owner)) { // protect this function
spin_unlock_bh(&appldata_ops_lock); spin_unlock(&appldata_ops_lock);
return -ENODEV; return -ENODEV;
} }
spin_unlock_bh(&appldata_ops_lock); spin_unlock(&appldata_ops_lock);
if (!*lenp || *ppos) { if (!*lenp || *ppos) {
*lenp = 0; *lenp = 0;
@ -451,10 +455,11 @@ appldata_generic_handler(ctl_table *ctl, int write, struct file *filp,
return -EFAULT; return -EFAULT;
} }
spin_lock_bh(&appldata_ops_lock); spin_lock(&appldata_ops_lock);
if ((buf[0] == '1') && (ops->active == 0)) { if ((buf[0] == '1') && (ops->active == 0)) {
if (!try_module_get(ops->owner)) { // protect tasklet // protect work queue callback
spin_unlock_bh(&appldata_ops_lock); if (!try_module_get(ops->owner)) {
spin_unlock(&appldata_ops_lock);
module_put(ops->owner); module_put(ops->owner);
return -ENODEV; return -ENODEV;
} }
@ -485,7 +490,7 @@ appldata_generic_handler(ctl_table *ctl, int write, struct file *filp,
} }
module_put(ops->owner); module_put(ops->owner);
} }
spin_unlock_bh(&appldata_ops_lock); spin_unlock(&appldata_ops_lock);
out: out:
*lenp = len; *lenp = len;
*ppos += len; *ppos += len;
@ -529,7 +534,7 @@ int appldata_register_ops(struct appldata_ops *ops)
} }
memset(ops->ctl_table, 0, 4*sizeof(struct ctl_table)); memset(ops->ctl_table, 0, 4*sizeof(struct ctl_table));
spin_lock_bh(&appldata_ops_lock); spin_lock(&appldata_ops_lock);
list_for_each(lh, &appldata_ops_list) { list_for_each(lh, &appldata_ops_list) {
tmp_ops = list_entry(lh, struct appldata_ops, list); tmp_ops = list_entry(lh, struct appldata_ops, list);
P_DEBUG("register_ops loop: %i) name = %s, ctl = %i\n", P_DEBUG("register_ops loop: %i) name = %s, ctl = %i\n",
@ -541,18 +546,18 @@ int appldata_register_ops(struct appldata_ops *ops)
APPLDATA_PROC_NAME_LENGTH) == 0) { APPLDATA_PROC_NAME_LENGTH) == 0) {
P_ERROR("Name \"%s\" already registered!\n", ops->name); P_ERROR("Name \"%s\" already registered!\n", ops->name);
kfree(ops->ctl_table); kfree(ops->ctl_table);
spin_unlock_bh(&appldata_ops_lock); spin_unlock(&appldata_ops_lock);
return -EBUSY; return -EBUSY;
} }
if (tmp_ops->ctl_nr == ops->ctl_nr) { if (tmp_ops->ctl_nr == ops->ctl_nr) {
P_ERROR("ctl_nr %i already registered!\n", ops->ctl_nr); P_ERROR("ctl_nr %i already registered!\n", ops->ctl_nr);
kfree(ops->ctl_table); kfree(ops->ctl_table);
spin_unlock_bh(&appldata_ops_lock); spin_unlock(&appldata_ops_lock);
return -EBUSY; return -EBUSY;
} }
} }
list_add(&ops->list, &appldata_ops_list); list_add(&ops->list, &appldata_ops_list);
spin_unlock_bh(&appldata_ops_lock); spin_unlock(&appldata_ops_lock);
ops->ctl_table[0].ctl_name = CTL_APPLDATA; ops->ctl_table[0].ctl_name = CTL_APPLDATA;
ops->ctl_table[0].procname = appldata_proc_name; ops->ctl_table[0].procname = appldata_proc_name;
@ -583,12 +588,12 @@ int appldata_register_ops(struct appldata_ops *ops)
*/ */
void appldata_unregister_ops(struct appldata_ops *ops) void appldata_unregister_ops(struct appldata_ops *ops)
{ {
spin_lock_bh(&appldata_ops_lock); spin_lock(&appldata_ops_lock);
unregister_sysctl_table(ops->sysctl_header); unregister_sysctl_table(ops->sysctl_header);
list_del(&ops->list); list_del(&ops->list);
kfree(ops->ctl_table); kfree(ops->ctl_table);
ops->ctl_table = NULL; ops->ctl_table = NULL;
spin_unlock_bh(&appldata_ops_lock); spin_unlock(&appldata_ops_lock);
P_INFO("%s-ops unregistered!\n", ops->name); P_INFO("%s-ops unregistered!\n", ops->name);
} }
/********************** module-ops management <END> **************************/ /********************** module-ops management <END> **************************/
@ -602,7 +607,7 @@ appldata_online_cpu(int cpu)
init_virt_timer(&per_cpu(appldata_timer, cpu)); init_virt_timer(&per_cpu(appldata_timer, cpu));
per_cpu(appldata_timer, cpu).function = appldata_timer_function; per_cpu(appldata_timer, cpu).function = appldata_timer_function;
per_cpu(appldata_timer, cpu).data = (unsigned long) per_cpu(appldata_timer, cpu).data = (unsigned long)
&appldata_tasklet_struct; &appldata_work;
atomic_inc(&appldata_expire_count); atomic_inc(&appldata_expire_count);
spin_lock(&appldata_timer_lock); spin_lock(&appldata_timer_lock);
__appldata_vtimer_setup(APPLDATA_MOD_TIMER); __appldata_vtimer_setup(APPLDATA_MOD_TIMER);
@ -615,7 +620,7 @@ appldata_offline_cpu(int cpu)
del_virt_timer(&per_cpu(appldata_timer, cpu)); del_virt_timer(&per_cpu(appldata_timer, cpu));
if (atomic_dec_and_test(&appldata_expire_count)) { if (atomic_dec_and_test(&appldata_expire_count)) {
atomic_set(&appldata_expire_count, num_online_cpus()); atomic_set(&appldata_expire_count, num_online_cpus());
tasklet_schedule(&appldata_tasklet_struct); queue_work(appldata_wq, &appldata_work);
} }
spin_lock(&appldata_timer_lock); spin_lock(&appldata_timer_lock);
__appldata_vtimer_setup(APPLDATA_MOD_TIMER); __appldata_vtimer_setup(APPLDATA_MOD_TIMER);
@ -648,7 +653,7 @@ static struct notifier_block __devinitdata appldata_nb = {
/* /*
* appldata_init() * appldata_init()
* *
* init timer and tasklet, register /proc entries * init timer, register /proc entries
*/ */
static int __init appldata_init(void) static int __init appldata_init(void)
{ {
@ -657,6 +662,12 @@ static int __init appldata_init(void)
P_DEBUG("sizeof(parameter_list) = %lu\n", P_DEBUG("sizeof(parameter_list) = %lu\n",
sizeof(struct appldata_parameter_list)); sizeof(struct appldata_parameter_list));
appldata_wq = create_singlethread_workqueue("appldata");
if (!appldata_wq) {
P_ERROR("Could not create work queue\n");
return -ENOMEM;
}
for_each_online_cpu(i) for_each_online_cpu(i)
appldata_online_cpu(i); appldata_online_cpu(i);
@ -670,7 +681,6 @@ static int __init appldata_init(void)
appldata_table[1].de->owner = THIS_MODULE; appldata_table[1].de->owner = THIS_MODULE;
#endif #endif
tasklet_init(&appldata_tasklet_struct, appldata_tasklet_function, 0);
P_DEBUG("Base interface initialized.\n"); P_DEBUG("Base interface initialized.\n");
return 0; return 0;
} }
@ -678,7 +688,7 @@ static int __init appldata_init(void)
/* /*
* appldata_exit() * appldata_exit()
* *
* stop timer and tasklet, unregister /proc entries * stop timer, unregister /proc entries
*/ */
static void __exit appldata_exit(void) static void __exit appldata_exit(void)
{ {
@ -690,7 +700,7 @@ static void __exit appldata_exit(void)
/* /*
* ops list should be empty, but just in case something went wrong... * ops list should be empty, but just in case something went wrong...
*/ */
spin_lock_bh(&appldata_ops_lock); spin_lock(&appldata_ops_lock);
list_for_each(lh, &appldata_ops_list) { list_for_each(lh, &appldata_ops_list) {
ops = list_entry(lh, struct appldata_ops, list); ops = list_entry(lh, struct appldata_ops, list);
rc = appldata_diag(ops->record_nr, APPLDATA_STOP_REC, rc = appldata_diag(ops->record_nr, APPLDATA_STOP_REC,
@ -700,7 +710,7 @@ static void __exit appldata_exit(void)
"return code: %d\n", ops->name, rc); "return code: %d\n", ops->name, rc);
} }
} }
spin_unlock_bh(&appldata_ops_lock); spin_unlock(&appldata_ops_lock);
for_each_online_cpu(i) for_each_online_cpu(i)
appldata_offline_cpu(i); appldata_offline_cpu(i);
@ -709,7 +719,7 @@ static void __exit appldata_exit(void)
unregister_sysctl_table(appldata_sysctl_header); unregister_sysctl_table(appldata_sysctl_header);
tasklet_kill(&appldata_tasklet_struct); destroy_workqueue(appldata_wq);
P_DEBUG("... module unloaded!\n"); P_DEBUG("... module unloaded!\n");
} }
/**************************** init / exit <END> ******************************/ /**************************** init / exit <END> ******************************/

2
arch/s390/appldata/appldata_mem.c
View file

@ -68,7 +68,7 @@ struct appldata_mem_data {
u64 pgmajfault; /* page faults (major only) */ u64 pgmajfault; /* page faults (major only) */
// <-- New in 2.6 // <-- New in 2.6
} appldata_mem_data; } __attribute__((packed)) appldata_mem_data;
static inline void appldata_debug_print(struct appldata_mem_data *mem_data) static inline void appldata_debug_print(struct appldata_mem_data *mem_data)

2
arch/s390/appldata/appldata_net_sum.c
View file

@ -57,7 +57,7 @@ struct appldata_net_sum_data {
u64 rx_dropped; /* no space in linux buffers */ u64 rx_dropped; /* no space in linux buffers */
u64 tx_dropped; /* no space available in linux */ u64 tx_dropped; /* no space available in linux */
u64 collisions; /* collisions while transmitting */ u64 collisions; /* collisions while transmitting */
} appldata_net_sum_data; } __attribute__((packed)) appldata_net_sum_data;
static inline void appldata_print_debug(struct appldata_net_sum_data *net_data) static inline void appldata_print_debug(struct appldata_net_sum_data *net_data)

4
arch/s390/appldata/appldata_os.c
View file

@ -49,7 +49,7 @@ struct appldata_os_per_cpu {
u32 per_cpu_softirq; /* ... spent in softirqs */ u32 per_cpu_softirq; /* ... spent in softirqs */
u32 per_cpu_iowait; /* ... spent while waiting for I/O */ u32 per_cpu_iowait; /* ... spent while waiting for I/O */
// <-- New in 2.6 // <-- New in 2.6
}; } __attribute__((packed));
struct appldata_os_data { struct appldata_os_data {
u64 timestamp; u64 timestamp;
@ -75,7 +75,7 @@ struct appldata_os_data {
/* per cpu data */ /* per cpu data */
struct appldata_os_per_cpu os_cpu[0]; struct appldata_os_per_cpu os_cpu[0];
}; } __attribute__((packed));
static struct appldata_os_data *appldata_os_data; static struct appldata_os_data *appldata_os_data;