Don't emit checksum histograms in ereport.fs.zfs.checksum events

The checksum histograms were intended to be used with ATA and parallel
SCSI, which are obsolete.  With modern storage hardware, they will
almost always look like white noise; all bits will be wrong.  They only
serve to bloat the event.  That's a particular problem on FreeBSD, where
events must fit into a 1016 byte buffer.

This fixes issue #14717 for RAIDZ pools, but not for mirror pools.

Reviewed-by: Brian Behlendorf <[email protected]>
Reviewed-by: Rich Ercolani <[email protected]>
Signed-off-by: Alan Somers <[email protected]>
Sponsored-by: Axcient
Closes #15052

1 files changed, 4 insertions, 21 deletions

diff --git a/module/zfs/zfs_fm.c b/module/zfs/zfs_fm.c
index 2754ceec8..9365ca500 100644
--- a/module/zfs/zfs_fm.c
+++ b/module/zfs/zfs_fm.c
@@ -754,10 +754,6 @@ zfs_ereport_start(nvlist_t **ereport_out, nvlist_t **detector_out,
 #define	MAX_RANGES		16
 
 typedef struct zfs_ecksum_info {
-	/* histograms of set and cleared bits by bit number in a 64-bit word */
-	uint8_t zei_histogram_set[sizeof (uint64_t) * NBBY];
-	uint8_t zei_histogram_cleared[sizeof (uint64_t) * NBBY];
-
 	/* inline arrays of bits set and cleared. */
 	uint64_t zei_bits_set[ZFM_MAX_INLINE];
 	uint64_t zei_bits_cleared[ZFM_MAX_INLINE];
@@ -781,7 +777,7 @@ typedef struct zfs_ecksum_info {
 } zfs_ecksum_info_t;
 
 static void
-update_histogram(uint64_t value_arg, uint8_t *hist, uint32_t *count)
+update_bad_bits(uint64_t value_arg, uint32_t *count)
 {
 	size_t i;
 	size_t bits = 0;
@@ -789,10 +785,8 @@ update_histogram(uint64_t value_arg, uint8_t *hist, uint32_t *count)
 
 	/* We store the bits in big-endian (largest-first) order */
 	for (i = 0; i < 64; i++) {
-		if (value & (1ull << i)) {
-			hist[63 - i] = MAX(hist[63 - i], hist[63 - i] + 1);
+		if (value & (1ull << i))
 			++bits;
-		}
 	}
 	/* update the count of bits changed */
 	*count += bits;
@@ -1010,10 +1004,8 @@ annotate_ecksum(nvlist_t *ereport, zio_bad_cksum_t *info,
 				offset++;
 			}
 
-			update_histogram(set, eip->zei_histogram_set,
-			    &eip->zei_range_sets[range]);
-			update_histogram(cleared, eip->zei_histogram_cleared,
-			    &eip->zei_range_clears[range]);
+			update_bad_bits(set, &eip->zei_range_sets[range]);
+			update_bad_bits(cleared, &eip->zei_range_clears[range]);
 		}
 
 		/* convert to byte offsets */
@@ -1049,15 +1041,6 @@ annotate_ecksum(nvlist_t *ereport, zio_bad_cksum_t *info,
 		    DATA_TYPE_UINT8_ARRAY,
 		    inline_size, (uint8_t *)eip->zei_bits_cleared,
 		    NULL);
-	} else {
-		fm_payload_set(ereport,
-		    FM_EREPORT_PAYLOAD_ZFS_BAD_SET_HISTOGRAM,
-		    DATA_TYPE_UINT8_ARRAY,
-		    NBBY * sizeof (uint64_t), eip->zei_histogram_set,
-		    FM_EREPORT_PAYLOAD_ZFS_BAD_CLEARED_HISTOGRAM,
-		    DATA_TYPE_UINT8_ARRAY,
-		    NBBY * sizeof (uint64_t), eip->zei_histogram_cleared,
-		    NULL);
 	}
 	return (eip);
 }