Add L2ARC tunables

The performance of the L2ARC can be tweaked by a number of tunables, which
may be necessary for different workloads:

     l2arc_write_max         max write bytes per interval
     l2arc_write_boost       extra write bytes during device warmup
     l2arc_noprefetch        skip caching prefetched buffers
     l2arc_headroom          number of max device writes to precache
     l2arc_feed_secs         seconds between L2ARC writing
     l2arc_feed_min_ms       min feed interval in milliseconds
     l2arc_feed_again        turbo L2ARC warmup
     l2arc_norw              no reads during writes

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #316

diff --git a/module/zfs/arc.c b/module/zfs/arc.c
index 7f1f747..ff631e6 100644 (file)
--- a/module/zfs/arc.c
+++ b/module/zfs/arc.c
@@ -582,14 +582,14 @@ uint64_t zfs_crc64_table[256];
 /*
  * L2ARC Performance Tunables
  */
-uint64_t l2arc_write_max = L2ARC_WRITE_SIZE;   /* default max write size */
-uint64_t l2arc_write_boost = L2ARC_WRITE_SIZE; /* extra write during warmup */
-uint64_t l2arc_headroom = L2ARC_HEADROOM;      /* number of dev writes */
-uint64_t l2arc_feed_secs = L2ARC_FEED_SECS;    /* interval seconds */
-uint64_t l2arc_feed_min_ms = L2ARC_FEED_MIN_MS;        /* min interval milliseconds */
-boolean_t l2arc_noprefetch = B_TRUE;           /* don't cache prefetch bufs */
-boolean_t l2arc_feed_again = B_TRUE;           /* turbo warmup */
-boolean_t l2arc_norw = B_TRUE;                 /* no reads during writes */
+unsigned long l2arc_write_max = L2ARC_WRITE_SIZE;      /* def max write size */
+unsigned long l2arc_write_boost = L2ARC_WRITE_SIZE;    /* extra warmup write */
+unsigned long l2arc_headroom = L2ARC_HEADROOM;         /* # of dev writes */
+unsigned long l2arc_feed_secs = L2ARC_FEED_SECS;       /* interval seconds */
+unsigned long l2arc_feed_min_ms = L2ARC_FEED_MIN_MS;   /* min interval msecs */
+int l2arc_noprefetch = B_TRUE;                 /* don't cache prefetch bufs */
+int l2arc_feed_again = B_TRUE;                 /* turbo warmup */
+int l2arc_norw = B_TRUE;                       /* no reads during writes */
 
 /*
  * L2ARC Internals
@@ -4796,4 +4796,28 @@ MODULE_PARM_DESC(zfs_arc_shrink_shift, "log2(fraction of arc to reclaim)");
 module_param(zfs_arc_p_min_shift, int, 0444);
 MODULE_PARM_DESC(zfs_arc_p_min_shift, "arc_c shift to calc min/max arc_p");
 
+module_param(l2arc_write_max, ulong, 0444);
+MODULE_PARM_DESC(l2arc_write_max, "Max write bytes per interval");
+
+module_param(l2arc_write_boost, ulong, 0444);
+MODULE_PARM_DESC(l2arc_write_boost, "Extra write bytes during device warmup");
+
+module_param(l2arc_headroom, ulong, 0444);
+MODULE_PARM_DESC(l2arc_headroom, "Number of max device writes to precache");
+
+module_param(l2arc_feed_secs, ulong, 0444);
+MODULE_PARM_DESC(l2arc_feed_secs, "Seconds between L2ARC writing");
+
+module_param(l2arc_feed_min_ms, ulong, 0444);
+MODULE_PARM_DESC(l2arc_feed_min_ms, "Min feed interval in milliseconds");
+
+module_param(l2arc_noprefetch, int, 0444);
+MODULE_PARM_DESC(l2arc_noprefetch, "Skip caching prefetched buffers");
+
+module_param(l2arc_feed_again, int, 0444);
+MODULE_PARM_DESC(l2arc_feed_again, "Turbo L2ARC warmup");
+
+module_param(l2arc_norw, int, 0444);
+MODULE_PARM_DESC(l2arc_norw, "No reads during writes");
+
 #endif