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Index: sys/x86/x86/mca.c
===================================================================
--- sys/x86/x86/mca.c
+++ sys/x86/x86/mca.c
@@ -86,7 +86,6 @@
struct mca_internal {
struct mca_record rec;
- int logged;
STAILQ_ENTRY(mca_internal) link;
};
@@ -101,6 +100,7 @@
static volatile int mca_count; /* Number of records stored. */
static int mca_banks; /* Number of per-CPU register banks. */
+static int mca_maxcount = -1; /* Limit on records stored. (-1 = unlimited) */
static SYSCTL_NODE(_hw, OID_AUTO, mca, CTLFLAG_RD, NULL,
"Machine Check Architecture");
@@ -122,9 +122,11 @@
&workaround_erratum383, 0,
"Is the workaround for Erratum 383 on AMD Family 10h processors enabled?");
+
static STAILQ_HEAD(, mca_internal) mca_freelist;
static int mca_freecount;
static STAILQ_HEAD(, mca_internal) mca_records;
+static STAILQ_HEAD(, mca_internal) mca_pending;
static struct callout mca_timer;
static int mca_ticks = 3600; /* Check hourly by default. */
static struct taskqueue *mca_tq;
@@ -560,16 +562,29 @@
mca_fill_freelist(void)
{
struct mca_internal *rec;
- int desired;
+ int desired_high, desired_low;
/*
* Ensure we have at least one record for each bank and one
- * record per CPU.
+ * record per CPU. Also, free excess entries which have crept onto
+ * our list. Do the frees first in case a concurrent thread begins
+ * using the free list entries while this thread is still working.
*/
- desired = imax(mp_ncpus, mca_banks);
+ desired_low = imax(mp_ncpus, mca_banks);
+ desired_high = imax(mp_ncpus, mca_banks) * 2;
mtx_lock_spin(&mca_lock);
- while (mca_freecount < desired) {
+ while (mca_freecount > desired_high) {
+ rec = STAILQ_FIRST(&mca_freelist);
+ KASSERT(rec != NULL, ("mca_freecount is %d, but list is empty",
+ mca_freecount));
+ STAILQ_REMOVE_HEAD(&mca_freelist, link);
+ mca_freecount--;
mtx_unlock_spin(&mca_lock);
+ free(rec, M_MCA);
+ mtx_lock_spin(&mca_lock);
+ }
+ while (mca_freecount < desired_low) {
+ mtx_unlock_spin(&mca_lock);
rec = malloc(sizeof(*rec), M_MCA, M_WAITOK);
mtx_lock_spin(&mca_lock);
STAILQ_INSERT_TAIL(&mca_freelist, rec, link);
@@ -607,9 +622,7 @@
}
rec->rec = *record;
- rec->logged = 0;
- STAILQ_INSERT_TAIL(&mca_records, rec, link);
- mca_count++;
+ STAILQ_INSERT_TAIL(&mca_pending, rec, link);
mtx_unlock_spin(&mca_lock);
if (mode == CMCI && !cold)
taskqueue_enqueue(mca_tq, &mca_refill_task);
@@ -796,6 +809,40 @@
}
/*
+ * Store a new record on the mca_records list while enforcing
+ * mca_maxcount.
+ */
+static void
+mca_store_record(struct mca_internal *mca)
+{
+
+ /*
+ * If we are storing no records (mca_maxcount == 0),
+ * we just free this record.
+ *
+ * If we are storing records (mca_maxcount != 0) and
+ * we have free space on the list, store the record
+ * and increment mca_count.
+ *
+ * If we are storing records and we do not have free
+ * space on the list, store the new record at the
+ * tail and free the oldest one from the head.
+ */
+ if (mca_maxcount != 0)
+ STAILQ_INSERT_TAIL(&mca_records, mca, link);
+ if (mca_maxcount < 0 || mca_count < mca_maxcount)
+ mca_count++;
+ else {
+ if (mca_maxcount != 0) {
+ mca = STAILQ_FIRST(&mca_records);
+ STAILQ_REMOVE_HEAD(&mca_records, link);
+ }
+ STAILQ_INSERT_TAIL(&mca_freelist, mca, link);
+ mca_freecount++;
+ }
+}
+
+/*
* Scan the machine check banks on all CPUs by binding to each CPU in
* turn. If any of the CPUs contained new machine check records, log
* them to the console.
@@ -821,13 +868,13 @@
thread_unlock(td);
if (count != 0) {
mtx_lock_spin(&mca_lock);
- STAILQ_FOREACH(mca, &mca_records, link) {
- if (!mca->logged) {
- mca->logged = 1;
- mca_log(&mca->rec);
- }
+ while ((mca = STAILQ_FIRST(&mca_pending)) != NULL) {
+ STAILQ_REMOVE_HEAD(&mca_pending, link);
+ mca_log(&mca->rec);
+ mca_store_record(mca);
}
mtx_unlock_spin(&mca_lock);
+ mca_fill_freelist();
}
}
@@ -853,6 +900,35 @@
return (0);
}
+static int
+sysctl_mca_maxcount(SYSCTL_HANDLER_ARGS)
+{
+ struct mca_internal *mca;
+ int error, i;
+ bool dorefill;
+
+ i = mca_maxcount;
+ error = sysctl_handle_int(oidp, &i, 0, req);
+ if (error || req->newptr == NULL)
+ return (error);
+ mtx_lock_spin(&mca_lock);
+ mca_maxcount = i;
+ dorefill = false;
+ if (mca_maxcount >= 0)
+ while (mca_count > mca_maxcount) {
+ mca = STAILQ_FIRST(&mca_records);
+ STAILQ_REMOVE_HEAD(&mca_records, link);
+ mca_count--;
+ STAILQ_INSERT_TAIL(&mca_freelist, mca, link);
+ mca_freecount++;
+ dorefill = true;
+ }
+ mtx_unlock_spin(&mca_lock);
+ if (dorefill && !cold)
+ taskqueue_enqueue(mca_tq, &mca_refill_task);
+ return (error);
+}
+
static void
mca_createtq(void *dummy)
{
@@ -933,6 +1009,7 @@
mca_banks = mcg_cap & MCG_CAP_COUNT;
mtx_init(&mca_lock, "mca", NULL, MTX_SPIN);
STAILQ_INIT(&mca_records);
+ STAILQ_INIT(&mca_pending);
TASK_INIT(&mca_scan_task, 0, mca_scan_cpus, NULL);
callout_init(&mca_timer, 1);
STAILQ_INIT(&mca_freelist);
@@ -942,6 +1019,10 @@
"count", CTLFLAG_RD, (int *)(uintptr_t)&mca_count, 0,
"Record count");
SYSCTL_ADD_PROC(NULL, SYSCTL_STATIC_CHILDREN(_hw_mca), OID_AUTO,
+ "maxcount", CTLTYPE_INT | CTLFLAG_RWTUN | CTLFLAG_MPSAFE,
+ &mca_maxcount, 0, sysctl_mca_maxcount, "I",
+ "Maximum record count (-1 is unlimited)");
+ SYSCTL_ADD_PROC(NULL, SYSCTL_STATIC_CHILDREN(_hw_mca), OID_AUTO,
"interval", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, &mca_ticks,
0, sysctl_positive_int, "I",
"Periodic interval in seconds to scan for machine checks");
@@ -1323,7 +1404,8 @@
cmc_intr(void)
{
struct mca_internal *mca;
- int count;
+ int count, savedfreecnt;
+ bool dorefill;
/*
* Serialize MCA bank scanning to prevent collisions from
@@ -1334,13 +1416,16 @@
/* If we found anything, log them to the console. */
if (count != 0) {
mtx_lock_spin(&mca_lock);
- STAILQ_FOREACH(mca, &mca_records, link) {
- if (!mca->logged) {
- mca->logged = 1;
- mca_log(&mca->rec);
- }
+ savedfreecnt = mca_freecount;
+ while ((mca = STAILQ_FIRST(&mca_pending)) != NULL) {
+ STAILQ_REMOVE_HEAD(&mca_pending, link);
+ mca_log(&mca->rec);
+ mca_store_record(mca);
}
+ dorefill = mca_freecount != savedfreecnt;
mtx_unlock_spin(&mca_lock);
+ if (dorefill && !cold)
+ taskqueue_enqueue(mca_tq, &mca_refill_task);
}
}
#endif

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