Messages in this thread Patch in this message | | | Subject | [PATCH] pre-decoded wchan output | From | Robert Love <> | Date | 17 Oct 2002 15:14:02 -0400 |
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Linus,
Attached patch implements a /proc/#/wchan which provides a pre-decoded wchan via kallsyms. I.e.,
[15:05:06]rml@phantasy:~$ cat /proc/1228/wchan wait4
Which is damn cool to me and will let ps(1) grab wchan information without having to parse System.map. It also means procps will not need System.map.
If CONFIG_KALLSYMS is enabled, /proc/#/wchan exists and exports the pre-decoded symbol name. The old wchan value in /proc/#/stat is hard-coded to zero.
If CONFIG_KALLSYMS is not enabled, /proc/#/wchan does not exist to conserve memory. In that case, the old wchan field in /proc/#/stat will export the usual wchan address.
This will not break procps, however the wchan field will be zero without an updated version if CONFIG_KALLSYMS is set. That is fine as 2.5 requires an updated procps anyhow. If CONFIG_KALLSYMS is not set, things are unchanged.
The procps patch is available at:
http://tech9.net/rml/procps/patches/procps-wchan-rml-2.0.10.20021011-1.patch
and ready for merging into procps CVS.
Patch is against current BK. Please, apply.
Robert Love
Implement /proc/#/wchan, a pre-decoded wchan
Documentation/filesystems/proc.txt | 1 + fs/proc/array.c | 10 ++++++---- fs/proc/base.c | 33 +++++++++++++++++++++++++++++++++ 3 files changed, 40 insertions(+), 4 deletions(-)
diff -urN linux-2.5.43/fs/proc/array.c linux/fs/proc/array.c --- linux-2.5.43/fs/proc/array.c 2002-10-16 22:55:13.000000000 -0400 +++ linux/fs/proc/array.c 2002-10-16 23:26:19.000000000 -0400 @@ -298,7 +298,7 @@ int proc_pid_stat(struct task_struct *task, char * buffer) { - unsigned long vsize, eip, esp, wchan; + unsigned long vsize, eip, esp; long priority, nice; int tty_pgrp = -1, tty_nr = 0; sigset_t sigign, sigcatch; @@ -331,8 +331,6 @@ up_read(&mm->mmap_sem); } - wchan = get_wchan(task); - collect_sigign_sigcatch(task, &sigign, &sigcatch); /* scale priority and nice values from timeslices to -20..20 */ @@ -384,7 +382,11 @@ task->blocked.sig[0] & 0x7fffffffUL, sigign .sig[0] & 0x7fffffffUL, sigcatch .sig[0] & 0x7fffffffUL, - wchan, +#ifndef CONFIG_KALLSYMS + get_wchan(task), +#else + 0UL, +#endif task->nswap, task->cnswap, task->exit_signal, diff -urN linux-2.5.43/fs/proc/base.c linux/fs/proc/base.c --- linux-2.5.43/fs/proc/base.c 2002-10-15 23:28:25.000000000 -0400 +++ linux/fs/proc/base.c 2002-10-16 23:24:17.000000000 -0400 @@ -28,6 +28,7 @@ #include <linux/namespace.h> #include <linux/mm.h> #include <linux/smp_lock.h> +#include <linux/kallsyms.h> /* * For hysterical raisins we keep the same inumbers as in the old procfs. @@ -54,6 +55,7 @@ PROC_PID_MAPS, PROC_PID_CPU, PROC_PID_MOUNTS, + PROC_PID_WCHAN, PROC_PID_FD_DIR = 0x8000, /* 0x8000-0xffff */ }; @@ -81,6 +83,9 @@ E(PROC_PID_ROOT, "root", S_IFLNK|S_IRWXUGO), E(PROC_PID_EXE, "exe", S_IFLNK|S_IRWXUGO), E(PROC_PID_MOUNTS, "mounts", S_IFREG|S_IRUGO), +#ifdef CONFIG_KALLSYMS + E(PROC_PID_WCHAN, "wchan", S_IFREG|S_IRUGO), +#endif {0,0,NULL,0} }; #undef E @@ -245,6 +250,28 @@ return res; } +#ifdef CONFIG_KALLSYMS +/* + * Provides a wchan file via kallsyms in a proper one-value-per-file format. + * Returns the resolved symbol. If that fails, simply return the address. + */ +static int proc_pid_wchan(struct task_struct *task, char *buffer) +{ + const char *sym_name, *ignore; + unsigned long wchan, dummy; + + wchan = get_wchan(task); + + if (!kallsyms_address_to_symbol(wchan, &ignore, &dummy, &dummy, + &ignore, &dummy, &dummy, &sym_name, + &dummy, &dummy)) { + return sprintf(buffer, "%lu", wchan); + } + + return sprintf(buffer, "%s", sym_name); +} +#endif + /************************************************************************/ /* Here the fs part begins */ /************************************************************************/ @@ -1016,6 +1043,12 @@ case PROC_PID_MOUNTS: inode->i_fop = &proc_mounts_operations; break; +#ifdef CONFIG_KALLSYMS + case PROC_PID_WCHAN: + inode->i_fop = &proc_info_file_operations; + ei->op.proc_read = proc_pid_wchan; + break; +#endif default: printk("procfs: impossible type (%d)",p->type); iput(inode); diff -urN linux-2.5.43/Documentation/filesystems/proc.txt linux/Documentation/filesystems/proc.txt --- linux-2.5.43/Documentation/filesystems/proc.txt 2002-10-15 23:27:48.000000000 -0400 +++ linux/Documentation/filesystems/proc.txt 2002-10-17 00:14:36.000000000 -0400 @@ -130,6 +130,7 @@ stat Process status statm Process memory status information status Process status in human readable form + wchan If CONFIG_KALLSYMS is set, a pre-decoded wchan .............................................................................. For example, to get the status information of a process, all you have to do is - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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