[Linux Device Driver (Third edition)] -- tasklet

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[Linux Device Driver (Third edition)] ---- taskletjit. c

#include <linux/module.h>#include <linux/moduleparam.h>#include <linux/init.h>#include <linux/time.h>#include <linux/timer.h>#include <linux/proc_fs.h>#include <linux/spinlock.h>#include <linux/interrupt.h>#include <asm/hardirq.h>#include <linux/sched.h>//jiffies#include <linux/kernel.h>#include <linux/types.h>//u64#include <linux/fs.h>//file_operations, file#include <linux/completion.h>#include <asm/uaccess.h>//copy_to_user & copy_from_userint delay = HZ;enum jit_files {JIT_BUSY,JIT_SCHED,JIT_QUEUE,JIT_SCHEDTO};int tdelay = 10;struct jit_data {struct timer_list timer;struct tasklet_struct tlet;int hi;wait_queue_head_t wait;unsigned long prevjiffies;unsigned char *buf;int loops;};int jit_fn(char *buf, char **start, off_t offset, int len, int *eof, void *data){unsigned long j0, j1;wait_queue_head_t wait;init_waitqueue_head(&wait);j0 = jiffies;j1 = j0 + delay;switch((long)data){case JIT_BUSY:while(time_before(jiffies, j1))cpu_relax();break;case JIT_SCHED:while(time_before(jiffies, j1))schedule();break;case JIT_QUEUE:wait_event_interruptible_timeout(wait, 0, delay);break;case JIT_SCHEDTO:set_current_state(TASK_INTERRUPTIBLE);schedule_timeout(delay);break;}j1 = jiffies;len = sprintf(buf, "%9li %9li\n", j0, j1);*start = buf;return len;}int jit_currentime(char *buf, char **start, off_t offset, int len, int *eof, void *data){struct timeval tv1;struct timespec tv2;unsigned long j1;u64 j2;j1 = jiffies;j2 = get_jiffies_64();do_gettimeofday(&tv1);tv2 = current_kernel_time();len = 0;len += sprintf(buf,"0x%08lx 0x%016Lx %10i.%06i\n"       "%40i.%09i\n",       j1, j2,       (int) tv1.tv_sec, (int) tv1.tv_usec,       (int) tv2.tv_sec, (int) tv2.tv_nsec);*start = buf;return len;}#define JIT_ASYNC_LOOPS 5void jit_timer_fn(unsigned long arg){struct jit_data *data = (struct jit_data *)arg;unsigned long j = jiffies;data->buf += sprintf(data->buf,"%9li%3li%i%6i%i%s\n",j,j-data->prevjiffies,in_interrupt()?1:0,current->pid, smp_processor_id(), current->comm);if(--data->loops){data->timer.expires += tdelay;data->prevjiffies = j;add_timer(&data->timer);}else{wake_up_interruptible(&data->wait);}}int jit_timer(char *buf, char **start, off_t offset, int len, int *eof, void *unused_data){struct jit_data *data;char *buf2 = buf;unsigned long j = jiffies;data = kmalloc(sizeof(*data), GFP_KERNEL);if(!data)return -ENOMEM;init_timer(&data->timer);init_waitqueue_head(&data->wait);buf2 += sprintf(buf2,"timedeltainirqpidcpucommand\n");buf2 += sprintf(buf2,"%9li%3li%i%6i%i%s\n",j,0L,in_interrupt()?1:0,current->pid, smp_processor_id(), current->comm);data->prevjiffies = j;data->buf = buf2;data->loops = JIT_ASYNC_LOOPS;data->timer.data = (unsigned long)data;data->timer.function = jit_timer_fn;data->timer.expires = j + tdelay;add_timer(&data->timer);wait_event_interruptible(data->wait, !data->loops);if(signal_pending(current))return -ERESTARTSYS;buf2 = data->buf;kfree(data);*eof =1;return buf2 - buf;}void jit_tasklet_fn(unsigned long arg){struct jit_data *data = (struct jit_data *)arg;unsigned long j = jiffies;data->buf += sprintf(data->buf,"%9li%3li%i%6i%i%s\n",j,j-data->prevjiffies,in_interrupt()?1:0,current->pid, smp_processor_id(), current->comm);if(--data->loops){data->prevjiffies = j;if(data->hi)tasklet_hi_schedule(&data->tlet);elsetasklet_schedule(&data->tlet);}else{wake_up_interruptible(&data->wait);}}int jit_tasklet(char *buf, char **start, off_t offset, int len, int *eof, void *arg){struct jit_data *data;char *buf2 = buf;unsigned long j = jiffies;long hi = (long)arg;data = kmalloc(sizeof(*data), GFP_KERNEL);if(!data)return -ENOMEM;init_waitqueue_head(&data->wait);buf2 += sprintf(buf2,"timedeltainirqpidcpucommand\n");buf2 += sprintf(buf2,"%9li%3li%i%6i%i%s\n",j,0L,in_interrupt()?1:0,current->pid, smp_processor_id(), current->comm);data->prevjiffies = j;data->buf = buf2;data->loops = JIT_ASYNC_LOOPS;tasklet_init(&data->tlet, jit_tasklet_fn,(unsigned long)data);data->hi = hi;if(hi)tasklet_hi_schedule(&data->tlet);elsetasklet_schedule(&data->tlet);wait_event_interruptible(data->wait, !data->loops);if(signal_pending(current))return -ERESTARTSYS;buf2 = data->buf;kfree(data);*eof =1;return buf2 - buf;}int __init jit_init(void){create_proc_read_entry("jit_currentime", 0, NULL, jit_currentime, NULL);create_proc_read_entry("jitbusy", 0, NULL, jit_fn, (void *)JIT_BUSY);create_proc_read_entry("jitsched", 0, NULL, jit_fn, (void *)JIT_SCHED);create_proc_read_entry("jitqueue", 0, NULL, jit_fn, (void *)JIT_QUEUE);create_proc_read_entry("jitschedto", 0, NULL, jit_fn, (void *)JIT_SCHEDTO);create_proc_read_entry("jittimer", 0, NULL, jit_timer, NULL);create_proc_read_entry("jittasklet", 0, NULL, jit_tasklet, NULL);create_proc_read_entry("jittasklethi", 0, NULL, jit_tasklet, (void *)1);return 0;}void __exit jit_exit(void){remove_proc_entry("jit_currentime", NULL);remove_proc_entry("jitbusy", NULL);remove_proc_entry("jitsched", NULL);remove_proc_entry("jitqueue", NULL);remove_proc_entry("jitschedto", NULL);remove_proc_entry("jittimer", NULL);remove_proc_entry("jittasklet", NULL);remove_proc_entry("jittasklethi", NULL);}MODULE_LICENSE("Dual BSD/GPL");module_init(jit_init);module_exit(jit_exit);

Makefile

obj-m:= jit.omodules-objs:= jit.oKDIR:= /usr/src/linux-headers-2.6.31-14-generic/PWD:= $(shell pwd)default:make -C $(KDIR) M=$(PWD) modulesclean:rm -rf *.ko *.mod.c *.mod.o *.o *.markers *.symvers *.order

Load

insmod jit.ko

Test

cat /proc/jittaskletcat /proc/jittasklethi

Uninstall

rmmod jit