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Allow DDB_CAPTURE_DEFAULTBUFSIZE and DDB_CAPTURE_MAXBUFSIZE to be

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overridden at compile-time using kernel options of the same names.

Rather than doing a compile-time CTASSERT of buffer sizes being
even multiples of block sizes, just adjust them at boottime, as
the failure mode is more user-friendly.

MFC after:	2 months
PR:		119993
Suggested by:	Scot Hetzel <swhetzel at gmail dot com>
This commit is contained in:
Robert Watson 2008-01-26 22:32:23 +00:00
parent 877729518e
commit f33dc69dfb
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=175694
2 changed files with 20 additions and 13 deletions
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2
sys/conf/options
View File

@ -48,6 +48,8 @@ TWA_FLASH_FIRMWARE opt_twa.h
# Debugging options.
DDB
DDB_CAPTURE_DEFAULTBUFSIZE opt_ddb.h
DDB_CAPTURE_MAXBUFSIZE opt_ddb.h
DDB_NUMSYM opt_ddb.h
GDB
KDB opt_global.h

31
sys/ddb/db_capture.c
View File

@ -32,6 +32,8 @@
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_ddb.h"
#include <sys/param.h>
#include <sys/conf.h>
#include <sys/kernel.h>
@ -52,11 +54,19 @@ __FBSDID("$FreeBSD$");
* kernel dumper routines without restarting the kernel, which is undesirable
* in the midst of debugging. Instead, we maintain a large static global
* buffer that we fill from DDB's output routines.
*
* We enforce an invariant at runtime that buffer sizes are even multiples of
* the textdump block size, which is a design choice that we might want to
* reconsider.
*/
static MALLOC_DEFINE(M_DDB_CAPTURE, "ddb_capture", "DDB capture buffer");
#ifndef DDB_CAPTURE_DEFAULTBUFSIZE
#define DDB_CAPTURE_DEFAULTBUFSIZE 48*1024
#endif
#ifndef DDB_CAPTURE_MAXBUFSIZE
#define DDB_CAPTURE_MAXBUFSIZE 512*1024
#endif
#define DDB_CAPTURE_FILENAME "ddb.txt" /* Captured DDB output. */
static char *db_capture_buf;
@ -81,24 +91,19 @@ SYSCTL_UINT(_debug_ddb_capture, OID_AUTO, maxbufsize, CTLFLAG_RD,
"Maximum value for debug.ddb.capture.bufsize");
/*
* Various compile-time assertions: defaults must be even multiples of
* textdump block size. We also perform run-time checking of
* user-configurable values.
*/
CTASSERT(DDB_CAPTURE_DEFAULTBUFSIZE % TEXTDUMP_BLOCKSIZE == 0);
CTASSERT(DDB_CAPTURE_MAXBUFSIZE % TEXTDUMP_BLOCKSIZE == 0);
/*
* Boot-time allocation of the DDB capture buffer, if any.
* Boot-time allocation of the DDB capture buffer, if any. Force all buffer
* sizes, including the maximum size, to be rounded to block sizes.
*/
static void
db_capture_sysinit(__unused void *dummy)
{
TUNABLE_INT_FETCH("debug.ddb.capture.bufsize", &db_capture_bufsize);
db_capture_maxbufsize = roundup(db_capture_maxbufsize,
TEXTDUMP_BLOCKSIZE);
db_capture_bufsize = roundup(db_capture_bufsize, TEXTDUMP_BLOCKSIZE);
if (db_capture_bufsize > DDB_CAPTURE_MAXBUFSIZE)
db_capture_bufsize = DDB_CAPTURE_MAXBUFSIZE;
if (db_capture_bufsize > db_capture_maxbufsize)
db_capture_bufsize = db_capture_maxbufsize;
if (db_capture_bufsize != 0)
db_capture_buf = malloc(db_capture_bufsize, M_DDB_CAPTURE,
M_WAITOK);
@ -121,7 +126,7 @@ sysctl_debug_ddb_capture_bufsize(SYSCTL_HANDLER_ARGS)
if (error || req->newptr == NULL)
return (error);
size = roundup(size, TEXTDUMP_BLOCKSIZE);
if (size > DDB_CAPTURE_MAXBUFSIZE)
if (size > db_capture_maxbufsize)
return (EINVAL);
sx_xlock(&db_capture_sx);
if (size != 0) {
@ -150,7 +155,7 @@ sysctl_debug_ddb_capture_bufsize(SYSCTL_HANDLER_ARGS)
KASSERT(db_capture_bufoff <= db_capture_bufsize,
("sysctl_debug_ddb_capture_bufsize: bufoff > bufsize"));
KASSERT(db_capture_bufsize <= DDB_CAPTURE_MAXBUFSIZE,
KASSERT(db_capture_bufsize <= db_capture_maxbufsize,
("sysctl_debug_ddb_capture_maxbufsize: bufsize > maxbufsize"));
return (0);