opnsense-src/sys/cddl/dev/dtrace/dtrace_sysctl.c
Andriy Gapon 7fdf0e8835 dtrace: add a knob to control maximum size of principal buffers
We had a hardcoded limit of 1/128-th of physical memory that was further
subdivided between all CPUs as principal buffers are allocated on the
per-CPU basis.  Actually, the buffers could use up 1/64-th of the
memmory because with the default switch policy there are two buffers per
CPU.

This commit allows to change that limit.

Note that the discussed limit is per dtrace command invocation.
The idea is to limit the size of a single malloc(9) call, not the total
memory size used by DTrace buffers.

Reviewed by:	markj
MFC after:	3 weeks
Differential Revision:	https://reviews.freebsd.org/D33648
2022-01-11 15:47:50 +02:00

104 lines
3.1 KiB
C

/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*
* $FreeBSD$
*
*/
/* Report registered DTrace providers. */
static int
sysctl_dtrace_providers(SYSCTL_HANDLER_ARGS)
{
char *p_name = NULL;
dtrace_provider_t
*prov = dtrace_provider;
int error = 0;
size_t len = 0;
mutex_enter(&dtrace_provider_lock);
mutex_enter(&dtrace_lock);
/* Compute the length of the space-separated provider name string. */
while (prov != NULL) {
len += strlen(prov->dtpv_name) + 1;
prov = prov->dtpv_next;
}
if ((p_name = kmem_alloc(len, KM_SLEEP)) == NULL)
error = ENOMEM;
else {
/* Start with an empty string. */
*p_name = '\0';
/* Point to the first provider again. */
prov = dtrace_provider;
/* Loop through the providers, appending the names. */
while (prov != NULL) {
if (prov != dtrace_provider)
(void) strlcat(p_name, " ", len);
(void) strlcat(p_name, prov->dtpv_name, len);
prov = prov->dtpv_next;
}
}
mutex_exit(&dtrace_lock);
mutex_exit(&dtrace_provider_lock);
if (p_name != NULL) {
error = sysctl_handle_string(oidp, p_name, len, req);
kmem_free(p_name, 0);
}
return (error);
}
SYSCTL_NODE(_debug, OID_AUTO, dtrace, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
"DTrace debug parameters");
SYSCTL_PROC(_debug_dtrace, OID_AUTO, providers,
CTLTYPE_STRING | CTLFLAG_MPSAFE | CTLFLAG_RD, 0, 0, sysctl_dtrace_providers,
"A", "available DTrace providers");
SYSCTL_NODE(_kern, OID_AUTO, dtrace, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
"DTrace parameters");
SYSCTL_INT(_kern_dtrace, OID_AUTO, err_verbose, CTLFLAG_RW,
&dtrace_err_verbose, 0,
"print DIF and DOF validation errors to the message buffer");
SYSCTL_INT(_kern_dtrace, OID_AUTO, memstr_max, CTLFLAG_RW, &dtrace_memstr_max,
0, "largest allowed argument to memstr(), 0 indicates no limit");
SYSCTL_QUAD(_kern_dtrace, OID_AUTO, dof_maxsize, CTLFLAG_RW,
&dtrace_dof_maxsize, 0, "largest allowed DOF table");
SYSCTL_QUAD(_kern_dtrace, OID_AUTO, helper_actions_max, CTLFLAG_RW,
&dtrace_helper_actions_max, 0, "maximum number of allowed helper actions");
SYSCTL_INT(_kern_dtrace, OID_AUTO, bufsize_max, CTLFLAG_RWTUN,
&dtrace_bufsize_max_frac, 0,
"maximum fraction (1/n-th) of physical memory for principal buffers");
SYSCTL_INT(_security_bsd, OID_AUTO, allow_destructive_dtrace, CTLFLAG_RDTUN,
&dtrace_allow_destructive, 1, "Allow destructive mode DTrace scripts");