kmem_cache_t *zio_buf_cache[SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT];
kmem_cache_t *zio_data_buf_cache[SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT];
int zio_bulk_flags = 0;
kmem_cache_t *zio_buf_cache[SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT];
kmem_cache_t *zio_data_buf_cache[SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT];
int zio_bulk_flags = 0;
zio_cons, zio_dest, NULL, NULL, NULL, KMC_KMEM);
zio_link_cache = kmem_cache_create("zio_link_cache",
sizeof (zio_link_t), 0, NULL, NULL, NULL, NULL, NULL, KMC_KMEM);
zio_cons, zio_dest, NULL, NULL, NULL, KMC_KMEM);
zio_link_cache = kmem_cache_create("zio_link_cache",
sizeof (zio_link_t), 0, NULL, NULL, NULL, NULL, NULL, KMC_KMEM);
+ zio_vdev_cache = kmem_cache_create("zio_vdev_cache", sizeof(vdev_io_t),
+ PAGESIZE, NULL, NULL, NULL, NULL, NULL, KMC_VMEM);
+ * Dedicated I/O buffers to ensure that memory fragmentation never prevents
+ * or significantly delays the issuing of a zio. These buffers are used
+ * to aggregate I/O and could be used for raidz stripes.
+ */
+void *
+zio_vdev_alloc(void)
+{
+ return (kmem_cache_alloc(zio_vdev_cache, KM_PUSHPAGE));
+}
+
+void
+zio_vdev_free(void *buf)
+{
+ kmem_cache_free(zio_vdev_cache, buf);
+
+}
+
+/*
* ==========================================================================
* Push and pop I/O transform buffers
* ==========================================================================
* ==========================================================================
* Push and pop I/O transform buffers
* ==========================================================================
- if (P2PHASE(zio->io_size, align) != 0) {
+ /*
+ * On Linux, we don't care about read alignment. The backing block
+ * device driver will take care of that for us.
+ * The only exception is raidz, which needs a full block for parity.
+ */
+ if (P2PHASE(zio->io_size, align) != 0 &&
+ (zio->io_type != ZIO_TYPE_READ ||
+ vd->vdev_ops == &vdev_raidz_ops)) {
uint64_t asize = P2ROUNDUP(zio->io_size, align);
char *abuf = zio_buf_alloc(asize);
uint64_t asize = P2ROUNDUP(zio->io_size, align);
char *abuf = zio_buf_alloc(asize);
if (zio->io_type == ZIO_TYPE_WRITE) {
bcopy(zio->io_data, abuf, zio->io_size);
bzero(abuf + zio->io_size, asize - zio->io_size);
}
zio_push_transform(zio, abuf, asize, asize, zio_subblock);
if (zio->io_type == ZIO_TYPE_WRITE) {
bcopy(zio->io_data, abuf, zio->io_size);
bzero(abuf + zio->io_size, asize - zio->io_size);
}
zio_push_transform(zio, abuf, asize, asize, zio_subblock);