Thread (26 messages) 26 messages, 8 authors, 2005-03-02

Re: [Lse-tech] Re: A common layer for Accounting packages

From: Evgeniy Polyakov <hidden>
Date: 2005-03-01 14:14:44
Also in: lkml

On Tue, 2005-03-01 at 14:53 +0100, Guillaume Thouvenin wrote:
On Tue, 2005-03-01 at 22:38 +0900, Kaigai Kohei wrote:
quoted
quoted
I tested without user space listeners and the cost is negligible. I will
test with a user space listeners and see the results. I'm going to run
the test this week after improving the mechanism that switch on/off the
sending of the message.
I'm also trying to mesure the process-creation/destruction performance on following three environment.
Archtechture: i686 / Distribution: Fedora Core 3
* Kernel Preemption is DISABLE
* SMP kernel but UP-machine / Not Hyper Threading
[1] 2.6.11-rc4-mm1 normal
[2] 2.6.11-rc4-mm1 with PAGG based Process Accounting Module
[3] 2.6.11-rc4-mm1 with fork-connector notification (it's enabled)

When 367th-fork() was called after fork-connector notification, kernel was locked up.
(User-Space-Listener has been also run until 366th-fork() notification was received)
I don't see this limit on my computer. I'm currently running the lmbench
with a new fork connector patch (one that enable/disable fork connector)
on an SMP computer. I will send results and the new patch tomorrow
because the test takes a while...

I'm using a small patch provided by Evgeniy and not included in the
2.6.11-rc4-mm1 tree.
2.6.11-rc4-mm1 tree does not have the latest connector.
Various fixes were added, not only that.

I run the latest patch Guillaume sent to me(with small updates), 
fork bomb with more than 100k forks passed already without any freeze.
I do not have numbers thought.
quoted hunk ↗ jump to hunk
Best regards,
Guillaume
--- orig/connector.c
+++ mod/connector.c
@@ -168,12 +168,11 @@
        group = NETLINK_CB((skb)).groups;
        msg = (struct cn_msg *)NLMSG_DATA(nlh);

-       if (msg->len != nlh->nlmsg_len - sizeof(*msg) - sizeof(*nlh)) {
+       if (NLMSG_SPACE(msg->len + sizeof(*msg)) != nlh->nlmsg_len) {
                printk(KERN_ERR "skb does not have enough length: "
-                               "requested msg->len=%u[%u], nlh->nlmsg_len=%u[%u], skb->len=%u[must be %u].\n",
-                               msg->len, NLMSG_SPACE(msg->len),
-                               nlh->nlmsg_len, nlh->nlmsg_len - sizeof(*nlh),
-                               skb->len, msg->len + sizeof(*msg));
+                               "requested msg->len=%u[%u], nlh->nlmsg_len=%u, skb->len=%u.\n",
+                               msg->len, NLMSG_SPACE(msg->len + sizeof(*msg)),
+                               nlh->nlmsg_len, skb->len);
                kfree_skb(skb);
                return -EINVAL;
        }
-- 
        Evgeniy Polyakov

Crash is better than data corruption -- Arthur Grabowski

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