Messages in this thread | | | Date | Mon, 27 Oct 2008 14:50:29 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH] v3 rudimentary tracing for Classic RCU |
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On Sun, Oct 26, 2008 at 02:59:30PM -0700, Paul E. McKenney wrote: > On Thu, Oct 23, 2008 at 07:12:09PM +0800, Lai Jiangshan wrote: > > > > trivial ported it to seq_file. > > seq_file are very good for the output buffer. > > Thank you for putting this together!!! Looks good at first glance -- > I will test it out.
So it does seem to operate correctly. I combined it with my patch and applied against 2.6.27 for ease of testing.
One question -- why the multi-line format? This would be a bit awkward on a 128-CPU system, let alone on a 4,096-CPU system. Or am I missing some trick here?
> Thanx, Paul > > > Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> > > --- > > diff --git a/kernel/rcuclassic_trace.c b/kernel/rcuclassic_trace.c > > index d19780b..f19217c > > --- a/kernel/rcuclassic_trace.c > > +++ b/kernel/rcuclassic_trace.c > > @@ -23,157 +23,167 @@ > > * Documentation/RCU > > * > > */ > > -#include <linux/types.h> > > -#include <linux/kernel.h> > > -#include <linux/init.h> > > -#include <linux/spinlock.h> > > -#include <linux/smp.h> > > #include <linux/rcupdate.h> > > -#include <linux/interrupt.h> > > -#include <linux/sched.h> > > -#include <asm/atomic.h> > > -#include <linux/bitops.h> > > #include <linux/module.h> > > -#include <linux/completion.h> > > -#include <linux/moduleparam.h> > > -#include <linux/percpu.h> > > -#include <linux/notifier.h> > > -#include <linux/cpu.h> > > -#include <linux/mutex.h> > > #include <linux/debugfs.h> > > +#include <linux/seq_file.h> > > > > -static DEFINE_MUTEX(rcuclassic_trace_mutex); > > -static char *rcuclassic_trace_buf; > > -#define RCUCLASSIC_TRACE_BUF_SIZE (128 * num_possible_cpus() + 100) > > +static struct rcu_data *get_rcu_data_bh(int cpu) > > +{ > > + return &per_cpu(rcu_bh_data, cpu); > > +} > > > > -static int print_one_rcu_data(struct rcu_data *rdp, char *buf, char *ebuf) > > +static struct rcu_data *get_rcu_data(int cpu) > > { > > - int cnt = 0; > > + return &per_cpu(rcu_data, cpu); > > +} > > > > +static int show_rcu_data(struct seq_file *m, void *v) > > +{ > > + struct rcu_data *rdp = v; > > if (!rdp->beenonline) > > return 0; > > - cnt += snprintf(&buf[cnt], ebuf - &buf[cnt], > > - "%3d%cqb=%ld b=%ld pq=%d qsp=%d ql=%ld bl=%ld\n", > > - rdp->cpu, cpu_is_offline(rdp->cpu) ? '!' : ' ', > > - rdp->quiescbatch, rdp->batch, rdp->passed_quiesc, > > - rdp->qs_pending, rdp->qlen, rdp->blimit); > > - return cnt; > > + > > + seq_printf(m, "processor\t: %d", rdp->cpu); > > + if (cpu_is_offline(rdp->cpu)) > > + seq_puts(m, "!\n"); > > + else > > + seq_puts(m, "\n"); > > + seq_printf(m, "quiescbatch\t: %ld\n", rdp->quiescbatch); > > + seq_printf(m, "batch\t: %ld\n", rdp->batch); > > + seq_printf(m, "passed_quiesc\t: %d\n", rdp->passed_quiesc); > > + seq_printf(m, "qs_pending\t: %d\n", rdp->qs_pending); > > + seq_printf(m, "qlen\t: %ld\n", rdp->qlen); > > + seq_printf(m, "blimit\t: %ld\n", rdp->blimit); > > + seq_puts(m, "\n\n"); > > + return 0; > > } > > > > -#define PRINT_RCU_DATA(name, buf, ebuf) \ > > - do { \ > > - int _p_r_d_i; \ > > - \ > > - for_each_possible_cpu(_p_r_d_i) \ > > - (buf) += print_one_rcu_data(&per_cpu(name, _p_r_d_i), \ > > - buf, ebuf); \ > > - } while (0) > > - > > -static ssize_t rcudata_read(struct file *filp, char __user *buffer, > > - size_t count, loff_t *ppos) > > +static void *c_start(struct seq_file *m, loff_t *pos) > > { > > - ssize_t bcount; > > - char *buf = rcuclassic_trace_buf; > > - char *ebuf = &rcuclassic_trace_buf[RCUCLASSIC_TRACE_BUF_SIZE]; > > - > > - mutex_lock(&rcuclassic_trace_mutex); > > - buf += snprintf(buf, ebuf - buf, "rcu:\n"); > > - PRINT_RCU_DATA(rcu_data, buf, ebuf); > > - buf += snprintf(buf, ebuf - buf, "rcu_bh:\n"); > > - PRINT_RCU_DATA(rcu_bh_data, buf, ebuf); > > - bcount = simple_read_from_buffer(buffer, count, ppos, > > - rcuclassic_trace_buf, strlen(rcuclassic_trace_buf)); > > - mutex_unlock(&rcuclassic_trace_mutex); > > - return bcount; > > + typedef struct rcu_data *(*get_data_func)(int); > > + > > + if (*pos == 0) /* just in case, cpu 0 is not the first */ > > + *pos = first_cpu(cpu_possible_map); > > + else > > + *pos = next_cpu_nr(*pos - 1, cpu_possible_map); > > + if ((*pos) < nr_cpu_ids) > > + return ((get_data_func)m->private)(*pos); > > + return NULL; > > } > > > > -static int print_one_rcu_ctrlblk(struct rcu_ctrlblk *rcp, char *buf, char *ebuf) > > +static void *c_next(struct seq_file *m, void *v, loff_t *pos) > > { > > - int cnt = 0; > > - > > - cnt += snprintf(&buf[cnt], ebuf - &buf[cnt], "cur=%ld completed=%ld " > > - "pending=%ld s=%d\n\t", > > - rcp->cur, rcp->completed, > > - rcp->pending, rcp->signaled); > > - cnt += cpulist_scnprintf(&buf[cnt], ebuf - &buf[cnt], rcp->cpumask); > > - cnt += snprintf(&buf[cnt], ebuf - &buf[cnt], "\n"); > > - return cnt; > > + (*pos)++; > > + return c_start(m, pos); > > } > > > > -static ssize_t rcucb_read(struct file *filp, char __user *buffer, > > - size_t count, loff_t *ppos) > > +static void c_stop(struct seq_file *m, void *v) > > { > > - ssize_t bcount; > > - char *buf = rcuclassic_trace_buf; > > - char *ebuf = &rcuclassic_trace_buf[RCUCLASSIC_TRACE_BUF_SIZE]; > > - > > - mutex_lock(&rcuclassic_trace_mutex); > > - buf += snprintf(buf, ebuf - buf, "rcu: "); > > - buf += print_one_rcu_ctrlblk(&rcu_ctrlblk, buf, ebuf); > > - buf += snprintf(buf, ebuf - buf, "rcu_bh: "); > > - buf += print_one_rcu_ctrlblk(&rcu_bh_ctrlblk, buf, ebuf); > > - buf += snprintf(buf, ebuf - buf, "online: "); > > - buf += cpulist_scnprintf(buf, ebuf - buf, cpu_online_map); > > - buf += snprintf(buf, ebuf - buf, "\n"); > > - bcount = simple_read_from_buffer(buffer, count, ppos, > > - rcuclassic_trace_buf, strlen(rcuclassic_trace_buf)); > > - mutex_unlock(&rcuclassic_trace_mutex); > > - return bcount; > > } > > > > -static struct file_operations rcudata_fops = { > > - .owner = THIS_MODULE, > > - .read = rcudata_read, > > +const struct seq_operations rcu_data_seq_op = { > > + .start = c_start, > > + .next = c_next, > > + .stop = c_stop, > > + .show = show_rcu_data, > > }; > > > > +static int rcu_data_open(struct inode *inode, struct file *file) > > +{ > > + int ret = seq_open(file, &rcu_data_seq_op); > > + if (ret) > > + return ret; > > + ((struct seq_file *)file->private_data)->private = inode->i_private; > > + return 0; > > +} > > + > > +static const struct file_operations rcu_data_fops = { > > + .owner = THIS_MODULE, > > + .open = rcu_data_open, > > + .read = seq_read, > > + .llseek = seq_lseek, > > + .release = seq_release, > > +}; > > + > > +static void print_one_rcu_ctrlblk(struct seq_file *m, struct rcu_ctrlblk *rcp) > > +{ > > + seq_printf(m, "cur=%ld completed=%ld pending=%ld s=%d\n\t", > > + rcp->cur, rcp->completed, rcp->pending, rcp->signaled); > > + seq_cpumask(m, &rcp->cpumask); > > + seq_puts(m, "\n"); > > +} > > + > > +static int show_rcucb(struct seq_file *m, void *unused) > > +{ > > + seq_puts(m, "rcu: "); > > + print_one_rcu_ctrlblk(m, &rcu_ctrlblk); > > + seq_puts(m, "rcu_bh: "); > > + print_one_rcu_ctrlblk(m, &rcu_bh_ctrlblk); > > + seq_puts(m, "online: "); > > + seq_cpumask(m, &cpu_online_map); > > + seq_puts(m, "\n"); > > + return 0; > > +} > > + > > +static int rcucb_open(struct inode *inode, struct file *file) > > +{ > > + return single_open(file, show_rcucb, NULL); > > +} > > + > > static struct file_operations rcucb_fops = { > > - .owner = THIS_MODULE, > > - .read = rcucb_read, > > + .owner = THIS_MODULE, > > + .open = rcucb_open, > > + .read = seq_read, > > + .llseek = seq_lseek, > > + .release = single_release, > > }; > > > > -static struct dentry *rcudir, *datadir, *cbdir; > > -static int rcuclassic_debugfs_init(void) > > +static struct dentry *rcudir, *rcu_bh_data_file, *rcu_data_file, *rcucb_file; > > + > > +static int __init rcuclassic_trace_init(void) > > { > > rcudir = debugfs_create_dir("rcu", NULL); > > if (!rcudir) > > goto out; > > - datadir = debugfs_create_file("rcudata", 0444, rcudir, > > - NULL, &rcudata_fops); > > - if (!datadir) > > - goto free_out; > > - cbdir = debugfs_create_file("rcucb", 0444, rcudir, NULL, &rcucb_fops); > > - if (!cbdir) > > - goto free_out; > > + > > + rcu_bh_data_file = debugfs_create_file("rcu_bh_data", 0444, rcudir, > > + get_rcu_data_bh, &rcu_data_fops); > > + if (!rcu_bh_data_file) > > + goto out_rcudir; > > + > > + rcu_data_file = debugfs_create_file("rcu_data", 0444, rcudir, > > + get_rcu_data, &rcu_data_fops); > > + if (!rcu_data_file) > > + goto out_rcudata_bh_file; > > + > > + rcucb_file = debugfs_create_file("rcucb", 0444, rcudir, > > + NULL, &rcucb_fops); > > + if (!rcucb_file) > > + goto out_rcudata_file; > > return 0; > > -free_out: > > - if (datadir) > > - debugfs_remove(datadir); > > + > > +out_rcudata_file: > > + debugfs_remove(rcu_data_file); > > +out_rcudata_bh_file: > > + debugfs_remove(rcu_bh_data_file); > > +out_rcudir: > > debugfs_remove(rcudir); > > out: > > return 1; > > } > > > > -static int __init rcuclassic_trace_init(void) > > -{ > > - int ret; > > - > > - rcuclassic_trace_buf = kmalloc(RCUCLASSIC_TRACE_BUF_SIZE, GFP_KERNEL); > > - if (!rcuclassic_trace_buf) > > - return 1; > > - ret = rcuclassic_debugfs_init(); > > - if (ret) > > - kfree(rcuclassic_trace_buf); > > - return ret; > > -} > > - > > static void __exit rcuclassic_trace_cleanup(void) > > { > > - debugfs_remove(datadir); > > - debugfs_remove(cbdir); > > + debugfs_remove(rcucb_file); > > + debugfs_remove(rcu_data_file); > > + debugfs_remove(rcu_bh_data_file); > > debugfs_remove(rcudir); > > - kfree(rcuclassic_trace_buf); > > } > > > > - > > module_init(rcuclassic_trace_init); > > module_exit(rcuclassic_trace_cleanup); > > + > > +MODULE_AUTHOR("Paul E. McKenney"); > > +MODULE_DESCRIPTION("Read-Copy Update tracing for classic implementation"); > > +MODULE_LICENSE("GPL"); > >
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