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Diffstat (limited to 'usr/src/uts/common/fs/zfs/vdev_cache.c')
-rw-r--r--usr/src/uts/common/fs/zfs/vdev_cache.c55
1 files changed, 33 insertions, 22 deletions
diff --git a/usr/src/uts/common/fs/zfs/vdev_cache.c b/usr/src/uts/common/fs/zfs/vdev_cache.c
index 67a8924b52..2d8795c660 100644
--- a/usr/src/uts/common/fs/zfs/vdev_cache.c
+++ b/usr/src/uts/common/fs/zfs/vdev_cache.c
@@ -60,9 +60,24 @@
* (4) Write. Update cache contents after write completion.
*
* (5) Evict. When allocating a new entry, we evict the oldest (LRU) entry
- * if the total cache size exceeds vc_size.
+ * if the total cache size exceeds zfs_vdev_cache_size.
*/
+/*
+ * These tunables are for performance analysis.
+ */
+/*
+ * All i/os smaller than zfs_vdev_cache_max will be turned into
+ * 1<<zfs_vdev_cache_bshift byte reads by the vdev_cache (aka software
+ * track buffer. At most zfs_vdev_cache_size bytes will be kept in each
+ * vdev's vdev_cache.
+ */
+int zfs_vdev_cache_max = 1<<14;
+int zfs_vdev_cache_size = 10ULL << 20;
+int zfs_vdev_cache_bshift = 16;
+
+#define VCBS (1 << zfs_vdev_cache_bshift)
+
static int
vdev_cache_offset_compare(const void *a1, const void *a2)
{
@@ -109,7 +124,7 @@ vdev_cache_evict(vdev_cache_t *vc, vdev_cache_entry_t *ve)
avl_remove(&vc->vc_lastused_tree, ve);
avl_remove(&vc->vc_offset_tree, ve);
- zio_buf_free(ve->ve_data, vc->vc_blocksize);
+ zio_buf_free(ve->ve_data, VCBS);
kmem_free(ve, sizeof (vdev_cache_entry_t));
}
@@ -122,20 +137,20 @@ static vdev_cache_entry_t *
vdev_cache_allocate(zio_t *zio)
{
vdev_cache_t *vc = &zio->io_vd->vdev_cache;
- uint64_t offset = P2ALIGN(zio->io_offset, vc->vc_blocksize);
+ uint64_t offset = P2ALIGN(zio->io_offset, VCBS);
vdev_cache_entry_t *ve;
ASSERT(MUTEX_HELD(&vc->vc_lock));
- if (vc->vc_size == 0)
+ if (zfs_vdev_cache_size == 0)
return (NULL);
/*
* If adding a new entry would exceed the cache size,
* evict the oldest entry (LRU).
*/
- if ((avl_numnodes(&vc->vc_lastused_tree) << vc->vc_bshift) >
- vc->vc_size) {
+ if ((avl_numnodes(&vc->vc_lastused_tree) << zfs_vdev_cache_bshift) >
+ zfs_vdev_cache_size) {
ve = avl_first(&vc->vc_lastused_tree);
if (ve->ve_fill_io != NULL) {
dprintf("can't evict in %p, still filling\n", vc);
@@ -148,7 +163,7 @@ vdev_cache_allocate(zio_t *zio)
ve = kmem_zalloc(sizeof (vdev_cache_entry_t), KM_SLEEP);
ve->ve_offset = offset;
ve->ve_lastused = lbolt;
- ve->ve_data = zio_buf_alloc(vc->vc_blocksize);
+ ve->ve_data = zio_buf_alloc(VCBS);
avl_add(&vc->vc_offset_tree, ve);
avl_add(&vc->vc_lastused_tree, ve);
@@ -159,7 +174,7 @@ vdev_cache_allocate(zio_t *zio)
static void
vdev_cache_hit(vdev_cache_t *vc, vdev_cache_entry_t *ve, zio_t *zio)
{
- uint64_t cache_phase = P2PHASE(zio->io_offset, vc->vc_blocksize);
+ uint64_t cache_phase = P2PHASE(zio->io_offset, VCBS);
ASSERT(MUTEX_HELD(&vc->vc_lock));
ASSERT(ve->ve_fill_io == NULL);
@@ -185,7 +200,7 @@ vdev_cache_fill(zio_t *zio)
vdev_cache_entry_t *ve = zio->io_private;
zio_t *dio;
- ASSERT(zio->io_size == vc->vc_blocksize);
+ ASSERT(zio->io_size == VCBS);
/*
* Add data to the cache.
@@ -227,8 +242,8 @@ vdev_cache_read(zio_t *zio)
{
vdev_cache_t *vc = &zio->io_vd->vdev_cache;
vdev_cache_entry_t *ve, ve_search;
- uint64_t cache_offset = P2ALIGN(zio->io_offset, vc->vc_blocksize);
- uint64_t cache_phase = P2PHASE(zio->io_offset, vc->vc_blocksize);
+ uint64_t cache_offset = P2ALIGN(zio->io_offset, VCBS);
+ uint64_t cache_phase = P2PHASE(zio->io_offset, VCBS);
zio_t *fio;
ASSERT(zio->io_type == ZIO_TYPE_READ);
@@ -236,17 +251,16 @@ vdev_cache_read(zio_t *zio)
if (zio->io_flags & ZIO_FLAG_DONT_CACHE)
return (EINVAL);
- if (zio->io_size > vc->vc_max)
+ if (zio->io_size > zfs_vdev_cache_max)
return (EOVERFLOW);
/*
* If the I/O straddles two or more cache blocks, don't cache it.
*/
- if (P2CROSS(zio->io_offset, zio->io_offset + zio->io_size - 1,
- vc->vc_blocksize))
+ if (P2CROSS(zio->io_offset, zio->io_offset + zio->io_size - 1, VCBS))
return (EXDEV);
- ASSERT(cache_phase + zio->io_size <= vc->vc_blocksize);
+ ASSERT(cache_phase + zio->io_size <= VCBS);
mutex_enter(&vc->vc_lock);
@@ -283,8 +297,7 @@ vdev_cache_read(zio_t *zio)
}
fio = zio_vdev_child_io(zio, NULL, zio->io_vd, cache_offset,
- ve->ve_data, vc->vc_blocksize, ZIO_TYPE_READ,
- ZIO_PRIORITY_CACHE_FILL,
+ ve->ve_data, VCBS, ZIO_TYPE_READ, ZIO_PRIORITY_CACHE_FILL,
ZIO_FLAG_DONT_CACHE | ZIO_FLAG_DONT_PROPAGATE |
ZIO_FLAG_DONT_RETRY | ZIO_FLAG_NOBOOKMARK,
vdev_cache_fill, ve);
@@ -309,8 +322,8 @@ vdev_cache_write(zio_t *zio)
vdev_cache_entry_t *ve, ve_search;
uint64_t io_start = zio->io_offset;
uint64_t io_end = io_start + zio->io_size;
- uint64_t min_offset = P2ALIGN(io_start, vc->vc_blocksize);
- uint64_t max_offset = P2ROUNDUP(io_end, vc->vc_blocksize);
+ uint64_t min_offset = P2ALIGN(io_start, VCBS);
+ uint64_t max_offset = P2ROUNDUP(io_end, VCBS);
avl_index_t where;
ASSERT(zio->io_type == ZIO_TYPE_WRITE);
@@ -325,7 +338,7 @@ vdev_cache_write(zio_t *zio)
while (ve != NULL && ve->ve_offset < max_offset) {
uint64_t start = MAX(ve->ve_offset, io_start);
- uint64_t end = MIN(ve->ve_offset + vc->vc_blocksize, io_end);
+ uint64_t end = MIN(ve->ve_offset + VCBS, io_end);
if (ve->ve_fill_io != NULL) {
ve->ve_missed_update = 1;
@@ -352,8 +365,6 @@ vdev_cache_init(vdev_t *vd)
avl_create(&vc->vc_lastused_tree, vdev_cache_lastused_compare,
sizeof (vdev_cache_entry_t),
offsetof(struct vdev_cache_entry, ve_lastused_node));
-
- vc->vc_blocksize = 1ULL << vc->vc_bshift;
}
void
generated by cgit v1.2.3 (git 2.46.0) at 2025-10-28 17:50:23 +0000