--- /dev/null
+/*
+ * 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
+ */
+
+#include <sys/zfs_context.h>
+#include <sys/spa_impl.h>
+
+/*
+ * Keeps stats on last N reads per spa_t, disabled by default.
+ */
+int zfs_read_history = 0;
+
+/*
+ * Include cache hits in history, disabled by default.
+ */
+int zfs_read_history_hits = 0;
+
+/*
+ * ==========================================================================
+ * SPA Read History Routines
+ * ==========================================================================
+ */
+
+/*
+ * Read statistics - Information exported regarding each arc_read call
+ */
+typedef struct spa_read_history {
+ uint64_t uid; /* unique identifier */
+ hrtime_t start; /* time read completed */
+ uint64_t objset; /* read from this objset */
+ uint64_t object; /* read of this object number */
+ uint64_t level; /* block's indirection level */
+ uint64_t blkid; /* read of this block id */
+ char origin[24]; /* read originated from here */
+ uint32_t aflags; /* ARC flags (cached, prefetch, etc.) */
+ pid_t pid; /* PID of task doing read */
+ char comm[16]; /* process name of task doing read */
+ list_node_t srh_link;
+} spa_read_history_t;
+
+static int
+spa_read_history_headers(char *buf, size_t size)
+{
+ size = snprintf(buf, size - 1, "%-8s %-16s %-8s %-8s %-8s %-8s %-8s "
+ "%-24s %-8s %-16s\n", "UID", "start", "objset", "object",
+ "level", "blkid", "aflags", "origin", "pid", "process");
+ buf[size] = '\0';
+
+ return (0);
+}
+
+static int
+spa_read_history_data(char *buf, size_t size, void *data)
+{
+ spa_read_history_t *srh = (spa_read_history_t *)data;
+
+ size = snprintf(buf, size - 1, "%-8llu %-16llu 0x%-6llx "
+ "%-8lli %-8lli %-8lli 0x%-6x %-24s %-8i %-16s\n",
+ (u_longlong_t)srh->uid, srh->start,
+ (longlong_t)srh->objset, (longlong_t)srh->object,
+ (longlong_t)srh->level, (longlong_t)srh->blkid,
+ srh->aflags, srh->origin, srh->pid, srh->comm);
+ buf[size] = '\0';
+
+ return (0);
+}
+
+/*
+ * Calculate the address for the next spa_stats_history_t entry. The
+ * ssh->lock will be held until ksp->ks_ndata entries are processed.
+ */
+static void *
+spa_read_history_addr(kstat_t *ksp, loff_t n)
+{
+ spa_t *spa = ksp->ks_private;
+ spa_stats_history_t *ssh = &spa->spa_stats.read_history;
+
+ ASSERT(MUTEX_HELD(&ssh->lock));
+
+ if (n == 0)
+ ssh->private = list_tail(&ssh->list);
+ else if (ssh->private)
+ ssh->private = list_prev(&ssh->list, ssh->private);
+
+ return (ssh->private);
+}
+
+/*
+ * When the kstat is written discard all spa_read_history_t entires. The
+ * ssh->lock will be held until ksp->ks_ndata entries are processed.
+ */
+static int
+spa_read_history_update(kstat_t *ksp, int rw)
+{
+ spa_t *spa = ksp->ks_private;
+ spa_stats_history_t *ssh = &spa->spa_stats.read_history;
+
+ if (rw == KSTAT_WRITE) {
+ spa_read_history_t *srh;
+
+ while ((srh = list_remove_head(&ssh->list))) {
+ ssh->size--;
+ kmem_free(srh, sizeof(spa_read_history_t));
+ }
+
+ ASSERT3U(ssh->size, ==, 0);
+ }
+
+ ksp->ks_ndata = ssh->size;
+ ksp->ks_data_size = ssh->size * sizeof(spa_read_history_t);
+
+ return (0);
+}
+
+static void
+spa_read_history_init(spa_t *spa)
+{
+ spa_stats_history_t *ssh = &spa->spa_stats.read_history;
+ char name[KSTAT_STRLEN];
+ kstat_t *ksp;
+
+ mutex_init(&ssh->lock, NULL, MUTEX_DEFAULT, NULL);
+ list_create(&ssh->list, sizeof (spa_read_history_t),
+ offsetof(spa_read_history_t, srh_link));
+
+ ssh->count = 0;
+ ssh->size = 0;
+ ssh->private = NULL;
+
+ (void) snprintf(name, KSTAT_STRLEN, "zfs/%s", spa_name(spa));
+ name[KSTAT_STRLEN-1] = '\0';
+
+ ksp = kstat_create(name, 0, "reads", "misc",
+ KSTAT_TYPE_RAW, 0, KSTAT_FLAG_VIRTUAL);
+ ssh->kstat = ksp;
+
+ if (ksp) {
+ ksp->ks_lock = &ssh->lock;
+ ksp->ks_data = NULL;
+ ksp->ks_private = spa;
+ ksp->ks_update = spa_read_history_update;
+ kstat_set_raw_ops(ksp, spa_read_history_headers,
+ spa_read_history_data, spa_read_history_addr);
+ kstat_install(ksp);
+ }
+}
+
+static void
+spa_read_history_destroy(spa_t *spa)
+{
+ spa_stats_history_t *ssh = &spa->spa_stats.read_history;
+ spa_read_history_t *srh;
+ kstat_t *ksp;
+
+ ksp = ssh->kstat;
+ if (ksp)
+ kstat_delete(ksp);
+
+ mutex_enter(&ssh->lock);
+ while ((srh = list_remove_head(&ssh->list))) {
+ ssh->size--;
+ kmem_free(srh, sizeof(spa_read_history_t));
+ }
+
+ ASSERT3U(ssh->size, ==, 0);
+ list_destroy(&ssh->list);
+ mutex_exit(&ssh->lock);
+
+ mutex_destroy(&ssh->lock);
+}
+
+void
+spa_read_history_add(spa_t *spa, const zbookmark_t *zb, uint32_t aflags)
+{
+ spa_stats_history_t *ssh = &spa->spa_stats.read_history;
+ spa_read_history_t *srh, *rm;
+
+ ASSERT3P(spa, !=, NULL);
+ ASSERT3P(zb, !=, NULL);
+
+ if (zfs_read_history == 0 && ssh->size == 0)
+ return;
+
+ if (zfs_read_history_hits == 0 && (aflags & ARC_CACHED))
+ return;
+
+ srh = kmem_zalloc(sizeof(spa_read_history_t), KM_PUSHPAGE);
+ strlcpy(srh->origin, zb->zb_func, sizeof(srh->origin));
+ strlcpy(srh->comm, getcomm(), sizeof(srh->comm));
+ srh->start = gethrtime();
+ srh->objset = zb->zb_objset;
+ srh->object = zb->zb_object;
+ srh->level = zb->zb_level;
+ srh->blkid = zb->zb_blkid;
+ srh->aflags = aflags;
+ srh->pid = getpid();
+
+ mutex_enter(&ssh->lock);
+
+ srh->uid = ssh->count++;
+ list_insert_head(&ssh->list, srh);
+ ssh->size++;
+
+ while (ssh->size > zfs_read_history) {
+ ssh->size--;
+ rm = list_remove_tail(&ssh->list);
+ kmem_free(rm, sizeof(spa_read_history_t));
+ }
+
+ mutex_exit(&ssh->lock);
+}
+
+void
+spa_stats_init(spa_t *spa)
+{
+ spa_read_history_init(spa);
+}
+
+void
+spa_stats_destroy(spa_t *spa)
+{
+ spa_read_history_destroy(spa);
+}
+
+#if defined(_KERNEL) && defined(HAVE_SPL)
+module_param(zfs_read_history, int, 0644);
+MODULE_PARM_DESC(zfs_read_history, "Historic statistics for the last N reads");
+
+module_param(zfs_read_history_hits, int, 0644);
+MODULE_PARM_DESC(zfs_read_history_hits, "Include cache hits in read history");
+#endif
projects / mirror_zfs.git / commitdiff