From: Peter Lieven <p...@kamp.de>
upcoming libnfs will have support for a read cache that can
significantly help to speed up requests since libnfs by design
circumvents the kernel cache.
Example:
qemu -cdrom nfs://127.0.0.1/iso/my.iso?pagecache=1024
The pagecache parameters takes the maximum amount of pages to
cache. A page in libnfs is always the NFS_BLKSIZE which is
4KB.
Signed-off-by: Peter Lieven <p...@kamp.de>
Reviewed-by: Jeff Cody <jc...@redhat.com>
Message-id: 1463662083-20814-3-git-send-email...@kamp.de
Signed-off-by: Jeff Cody <jc...@redhat.com>
---
block/nfs.c | 37 ++++++++++++++++++++++++++++++++++++-
1 file changed, 36 insertions(+), 1 deletion(-)
diff --git a/block/nfs.c b/block/nfs.c
index 60be45e..15d6832 100644
--- a/block/nfs.c
+++ b/block/nfs.c
@@ -38,6 +38,7 @@
#include <nfsc/libnfs.h>
#define QEMU_NFS_MAX_READAHEAD_SIZE 1048576
+#define QEMU_NFS_MAX_PAGECACHE_SIZE (8388608 / NFS_BLKSIZE)
#define QEMU_NFS_MAX_DEBUG_LEVEL 2
typedef struct NFSClient {
@@ -342,6 +343,26 @@ static int64_t nfs_client_open(NFSClient *client, const
char *filename,
val = QEMU_NFS_MAX_READAHEAD_SIZE;
}
nfs_set_readahead(client->context, val);
+#ifdef LIBNFS_FEATURE_PAGECACHE
+ nfs_set_pagecache_ttl(client->context, 0);
+#endif
+ client->cache_used = true;
+#endif
+#ifdef LIBNFS_FEATURE_PAGECACHE
+ nfs_set_pagecache_ttl(client->context, 0);
+ } else if (!strcmp(qp->p[i].name, "pagecache")) {
+ if (open_flags & BDRV_O_NOCACHE) {
+ error_setg(errp, "Cannot enable NFS pagecache "
+ "if cache.direct = on");
+ goto fail;
+ }
+ if (val > QEMU_NFS_MAX_PAGECACHE_SIZE) {
+ error_report("NFS Warning: Truncating NFS pagecache"
+ " size to %d pages", QEMU_NFS_MAX_PAGECACHE_SIZE);
+ val = QEMU_NFS_MAX_PAGECACHE_SIZE;
+ }
+ nfs_set_pagecache(client->context, val);
+ nfs_set_pagecache_ttl(client->context, 0);
client->cache_used = true;
#endif
#ifdef LIBNFS_FEATURE_DEBUG
@@ -524,7 +545,8 @@ static int nfs_reopen_prepare(BDRVReopenState *state,
}
if ((state->flags & BDRV_O_NOCACHE) && client->cache_used) {
- error_setg(errp, "Cannot disable cache if libnfs readahead is
enabled");
+ error_setg(errp, "Cannot disable cache if libnfs readahead or"
+ " pagecache is enabled");
return -EINVAL;
}
@@ -542,6 +564,15 @@ static int nfs_reopen_prepare(BDRVReopenState *state,
return 0;
}
+#ifdef LIBNFS_FEATURE_PAGECACHE
+static void nfs_invalidate_cache(BlockDriverState *bs,
+ Error **errp)
+{
+ NFSClient *client = bs->opaque;
+ nfs_pagecache_invalidate(client->context, client->fh);
+}
+#endif
+
static BlockDriver bdrv_nfs = {
.format_name = "nfs",
.protocol_name = "nfs",
@@ -565,6 +596,10 @@ static BlockDriver bdrv_nfs = {
.bdrv_detach_aio_context = nfs_detach_aio_context,
.bdrv_attach_aio_context = nfs_attach_aio_context,
+
+#ifdef LIBNFS_FEATURE_PAGECACHE
+ .bdrv_invalidate_cache = nfs_invalidate_cache,
+#endif
};
static void nfs_block_init(void)
--
1.9.3
