Author: adrian
Date: Mon Nov 2 03:36:15 2015
New Revision: 290258
URL: https://svnweb.freebsd.org/changeset/base/290258
Log:
mips: rate limit the trap handler output; add pid/tid/program name.
I discovered that we're logging each trap, which gets pretty spendy;
and there wasn't any further information on the pid/tid/progname involved.
I originally noticed this because I don't attach anything to /dev/log and so
the log() output stays going to the kernel. That's an oops on my part, but
I'm glad I did it.
This commit adds the following:
* a rate limiter, which could do with some eyeballs/ideas on how to
make it more predictable on SMP;
* log pid, tid, progname (comm) as part of the output.
I now get output like this:
Unaligned Load Word: pid=621 (pmcstat), tid=100060, pc=0xffffffff803ae898,
badvaddr=0x40a10055
Unaligned Load Word: pid=621 (pmcstat), tid=100060, pc=0xffffffff803ae898,
badvaddr=0x40a10051
Unaligned Load Word: pid=621 (pmcstat), tid=100060, pc=0xffffffff803ae898,
badvaddr=0x40a1004d
Unaligned Load Word: pid=602 (login), tid=100042, pc=0xffffffff803ae898,
badvaddr=0x401159
Unaligned Load Word: pid=602 (login), tid=100042, pc=0xffffffff803ae898,
badvaddr=0x401155
Unaligned Load Word: pid=602 (login), tid=100042, pc=0xffffffff803ae898,
badvaddr=0x401151
.. which makes it much easier to start figuring out what/where to fix.
The pc looks suss (it looks like it's in kernel space); I'll dig into that
one next.
Tested:
* AR9331 SoC (Carambola2)
Modified:
head/sys/mips/mips/trap.c
Modified: head/sys/mips/mips/trap.c
==============================================================================
--- head/sys/mips/mips/trap.c Mon Nov 2 03:14:37 2015 (r290257)
+++ head/sys/mips/mips/trap.c Mon Nov 2 03:36:15 2015 (r290258)
@@ -1660,11 +1660,25 @@ mips_unaligned_load_store(struct trapfra
}
+/*
+ * XXX TODO: SMP?
+ */
+static struct timeval unaligned_lasterr;
+static int unaligned_curerr;
+
+static int unaligned_pps_log_limit = 4;
+
+SYSCTL_INT(_machdep, OID_AUTO, unaligned_log_pps_limit, CTLFLAG_RWTUN,
+ &unaligned_pps_log_limit, 0,
+ "limit number of userland unaligned log messages per second");
+
static int
emulate_unaligned_access(struct trapframe *frame, int mode)
{
register_t pc;
int access_type = 0;
+ struct thread *td = curthread;
+ struct proc *p = curproc;
pc = frame->pc + (DELAYBRANCH(frame->cause) ? 4 : 0);
@@ -1691,9 +1705,19 @@ emulate_unaligned_access(struct trapfram
else
frame->pc += 4;
- log(LOG_INFO, "Unaligned %s: pc=%#jx, badvaddr=%#jx\n",
- access_name[access_type - 1], (intmax_t)pc,
- (intmax_t)frame->badvaddr);
+ if (ppsratecheck(&unaligned_lasterr,
+ &unaligned_curerr, unaligned_pps_log_limit)) {
+ /* XXX TODO: keep global/tid/pid counters? */
+ log(LOG_INFO,
+ "Unaligned %s: pid=%ld (%s), tid=%ld, "
+ "pc=%#jx, badvaddr=%#jx\n",
+ access_name[access_type - 1],
+ (long) p->p_pid,
+ p->p_comm,
+ (long) td->td_tid,
+ (intmax_t)pc,
+ (intmax_t)frame->badvaddr);
+ }
}
}
return access_type;
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