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Message-ID: <20070813235802.GA20093@hmsreliant.think-freely.org>
Date: Mon, 13 Aug 2007 19:58:02 -0400
From: Neil Horman <nhorman@...driver.com>
To: Alexey Dobriyan <adobriyan@...il.com>
Cc: Ingo Oeser <ioe-lkml@...eria.de>, linux-kernel@...r.kernel.org,
akpm@...ux-foundation.org, torvalds@...ux-foundation.org
Subject: Re: [PATCH]: proc: export a processes resource limits via proc/<pid>
On Tue, Aug 14, 2007 at 01:04:02AM +0400, Alexey Dobriyan wrote:
> On Mon, Aug 13, 2007 at 04:11:30PM -0400, Neil Horman wrote:
> > --- a/fs/proc/base.c
> > +++ b/fs/proc/base.c
> > @@ -323,6 +324,68 @@ static int proc_oom_score(struct task_struct *task, char *buffer)
> > return sprintf(buffer, "%lu\n", points);
> > }
> >
> > +struct limit_names {
> > + char *name;
> > + char *unit;
> > +};
> > +
> > +static const struct limit_names lnames[RLIM_NLIMITS] = {
> > + [RLIMIT_CPU] = {"Max cpu time", "ms"},
> > + [RLIMIT_FSIZE] = {"Max file size", "bytes"},
> > + [RLIMIT_DATA] = {"Max data size", "bytes"},
> > + [RLIMIT_STACK] = {"Max stack size", "bytes"},
> > + [RLIMIT_CORE] = {"Max core file size", "bytes"},
> > + [RLIMIT_RSS] = {"Max resident set", "bytes"},
> > + [RLIMIT_NPROC] = {"Max processes", "processes"},
> > + [RLIMIT_NOFILE] = {"Max open files", "files"},
> > + [RLIMIT_MEMLOCK] = {"Max locked memory", "bytes"},
> > + [RLIMIT_AS] = {"Max address space", "bytes"},
> > + [RLIMIT_LOCKS] = {"Max file locks", "locks"},
> > + [RLIMIT_SIGPENDING] = {"Max pending signals", "signals"},
>
> this and processes should be left empty methinks, because max signals is
> in fact unitless.
>
not sure I agree with that. According to the man page, RLIMIT_SIGPENDING is
counted in number of signals and RLIMIT_NPROC is counted as a number of
processes.
> > + [RLIMIT_MSGQUEUE] = {"Max msgqueue size", "bytes"},
> > + [RLIMIT_NICE] = {"Max nice priority", NULL},
> > + [RLIMIT_RTPRIO] = {"Max realtime priority", NULL},
> > +};
>
> aha! trailing whitespace!
>
Fixed :)
> > +static int proc_pid_limits(struct task_struct *task, char *buffer)
> > +{
> > + unsigned int i;
> > + int count = 0;
> > + char *bufptr = buffer;
> > +
> > + struct rlimit rlim[RLIM_NLIMITS];
> > +
> > + read_lock(&tasklist_lock);
> > + memcpy(rlim, task->signal->rlim, (sizeof(struct rlimit) * RLIM_NLIMITS));
>
> unneeded (, )
>
I prefer to explicitly show order of operations, but I'm wierd that way, so I'll
change it :)
> > + read_unlock(&tasklist_lock);
>
> hmm, fork copies this under task lock of group leader and system calls
> in sys.c too. What's up?
>
> I'm sure it will give you nonsensical output because of wrong locks but
> I haven't checked.
>
I don't think so, I borrowed the code there from sys_getrlimit, which also reds
task->signal->rlim (only for one element instead of the whole array, so if its
broken here it should be broken there, but I don't see how.
> FWIW, it survived ~1 hour of cat /proc/*/limits, mini fork bombs, LTP,
> gdb testsuite and one sooper sikrit proggie. on core2
>
Its survived for a few days for me (while true; do cat /proc/*/limits;done),
with not noticible side effects (other than a slightly higher CPU load :)).
New patch with the ()'s and whitespace fixed.
Regards
Neil
Signed-off-by: Neil Horman <nhorman@...driver.com>
base.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 65 insertions(+)
diff --git a/fs/proc/base.c b/fs/proc/base.c
index ed2b224..b3ddf08 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -74,6 +74,7 @@
#include <linux/nsproxy.h>
#include <linux/oom.h>
#include <linux/elf.h>
+#include <asm/resource.h>
#include "internal.h"
/* NOTE:
@@ -323,6 +324,68 @@ static int proc_oom_score(struct task_struct *task, char *buffer)
return sprintf(buffer, "%lu\n", points);
}
+struct limit_names {
+ char *name;
+ char *unit;
+};
+
+static const struct limit_names lnames[RLIM_NLIMITS] = {
+ [RLIMIT_CPU] = {"Max cpu time", "ms"},
+ [RLIMIT_FSIZE] = {"Max file size", "bytes"},
+ [RLIMIT_DATA] = {"Max data size", "bytes"},
+ [RLIMIT_STACK] = {"Max stack size", "bytes"},
+ [RLIMIT_CORE] = {"Max core file size", "bytes"},
+ [RLIMIT_RSS] = {"Max resident set", "bytes"},
+ [RLIMIT_NPROC] = {"Max processes", "processes"},
+ [RLIMIT_NOFILE] = {"Max open files", "files"},
+ [RLIMIT_MEMLOCK] = {"Max locked memory", "bytes"},
+ [RLIMIT_AS] = {"Max address space", "bytes"},
+ [RLIMIT_LOCKS] = {"Max file locks", "locks"},
+ [RLIMIT_SIGPENDING] = {"Max pending signals", "signals"},
+ [RLIMIT_MSGQUEUE] = {"Max msgqueue size", "bytes"},
+ [RLIMIT_NICE] = {"Max nice priority", NULL},
+ [RLIMIT_RTPRIO] = {"Max realtime priority", NULL},
+};
+
+/* Display limits for a process */
+static int proc_pid_limits(struct task_struct *task, char *buffer)
+{
+ unsigned int i;
+ int count = 0;
+ char *bufptr = buffer;
+
+ struct rlimit rlim[RLIM_NLIMITS];
+
+ read_lock(&tasklist_lock);
+ memcpy(rlim, task->signal->rlim, sizeof(struct rlimit) * RLIM_NLIMITS);
+ read_unlock(&tasklist_lock);
+
+ /*
+ * print the file header
+ */
+ count += sprintf(&bufptr[count], "%-25s %-20s %-20s %-10s\n",
+ "Limit","Soft Limit","Hard Limit","Units");
+
+ for (i=0; i < RLIM_NLIMITS; i++) {
+ if (rlim[i].rlim_cur == RLIM_INFINITY)
+ count += sprintf(&bufptr[count], "%-25s %-20s ", lnames[i].name,"unlimited");
+ else
+ count += sprintf(&bufptr[count], "%-25s %-20lu ", lnames[i].name, rlim[i].rlim_cur);
+
+ if (rlim[i].rlim_max == RLIM_INFINITY)
+ count += sprintf(&bufptr[count], "%-20s ","unlimited");
+ else
+ count += sprintf(&bufptr[count], "%-20lu ", rlim[i].rlim_max);
+
+ if (lnames[i].unit)
+ count += sprintf(&bufptr[count],"%-10s\n", lnames[i].unit);
+ else
+ count += sprintf(&bufptr[count],"\n");
+ }
+
+ return count;
+}
+
/************************************************************************/
/* Here the fs part begins */
/************************************************************************/
@@ -2017,6 +2080,7 @@ static const struct pid_entry tgid_base_stuff[] = {
INF("environ", S_IRUSR, pid_environ),
INF("auxv", S_IRUSR, pid_auxv),
INF("status", S_IRUGO, pid_status),
+ INF("limits", S_IRUSR, pid_limits),
#ifdef CONFIG_SCHED_DEBUG
REG("sched", S_IRUGO|S_IWUSR, pid_sched),
#endif
@@ -2310,6 +2374,7 @@ static const struct pid_entry tid_base_stuff[] = {
INF("environ", S_IRUSR, pid_environ),
INF("auxv", S_IRUSR, pid_auxv),
INF("status", S_IRUGO, pid_status),
+ INF("limits", S_IRUSR, pid_limits),
#ifdef CONFIG_SCHED_DEBUG
REG("sched", S_IRUGO|S_IWUSR, pid_sched),
#endif
--
/***************************************************
*Neil Horman
*Software Engineer
*Red Hat, Inc.
*nhorman@...driver.com
*gpg keyid: 1024D / 0x92A74FA1
*http://pgp.mit.edu
***************************************************/
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