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[Qemu-devel] [PATCH v2 17/18] block: default min_io_size to host block s
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PATCH v2 17/18] block: default min_io_size to host block size when doing rmw |
Date: |
Thu, 26 Jan 2012 18:22:48 +0100 |
Same as the previous patch. However, since the min_io_size is a byte
value rather than an exponent, we want to make sure that we pass a 0
when running on 512b-sector disks.
Signed-off-by: Paolo Bonzini <address@hidden>
---
block.c | 17 +++++++++++++++++
block.h | 1 +
hw/scsi-disk.c | 2 +-
hw/virtio-blk.c | 2 +-
4 files changed, 20 insertions(+), 2 deletions(-)
diff --git a/block.c b/block.c
index 0fce655..4880143 100644
--- a/block.c
+++ b/block.c
@@ -4153,3 +4153,20 @@ unsigned int get_physical_block_exp(BlockConf *conf)
return exp;
}
+
+unsigned int get_min_io_size(BlockConf *conf)
+{
+ if (conf->min_io_size || !conf->bs) {
+ return conf->min_io_size;
+ }
+
+ /* Ask the OS to avoid read-modify-write cycles. But when running
+ * on 512b-sector disks, we should not modify the parameters that
+ * guests had seen so far.
+ */
+ if (conf->bs->host_block_size > conf->logical_block_size) {
+ return conf->bs->host_block_size;
+ }
+
+ return 0;
+}
diff --git a/block.h b/block.h
index 4270f67..ad1d18c 100644
--- a/block.h
+++ b/block.h
@@ -406,6 +406,7 @@ typedef struct BlockConf {
} BlockConf;
unsigned int get_physical_block_exp(BlockConf *conf);
+unsigned int get_min_io_size(BlockConf *conf);
#define DEFINE_BLOCK_PROPERTIES(_state, _conf) \
DEFINE_PROP_DRIVE("drive", _state, _conf.bs), \
diff --git a/hw/scsi-disk.c b/hw/scsi-disk.c
index 4f370a6..032ccf1 100644
--- a/hw/scsi-disk.c
+++ b/hw/scsi-disk.c
@@ -429,7 +429,7 @@ static int scsi_disk_emulate_inquiry(SCSIRequest *req,
uint8_t *outbuf)
unsigned int unmap_sectors =
s->qdev.conf.discard_granularity / s->qdev.blocksize;
unsigned int min_io_size =
- s->qdev.conf.min_io_size / s->qdev.blocksize;
+ get_min_io_size(&s->qdev.conf) / s->qdev.blocksize;
unsigned int opt_io_size =
s->qdev.conf.opt_io_size / s->qdev.blocksize;
diff --git a/hw/virtio-blk.c b/hw/virtio-blk.c
index 7c44a1f..06b5c0d 100644
--- a/hw/virtio-blk.c
+++ b/hw/virtio-blk.c
@@ -491,7 +491,7 @@ static void virtio_blk_update_config(VirtIODevice *vdev,
uint8_t *config)
stl_raw(&blkcfg.seg_max, 128 - 2);
stw_raw(&blkcfg.cylinders, cylinders);
stl_raw(&blkcfg.blk_size, blk_size);
- stw_raw(&blkcfg.min_io_size, s->conf->min_io_size / blk_size);
+ stw_raw(&blkcfg.min_io_size, get_min_io_size(s->conf) / blk_size);
stw_raw(&blkcfg.opt_io_size, s->conf->opt_io_size / blk_size);
blkcfg.heads = heads;
blkcfg.sectors = secs & ~s->sector_mask;
--
1.7.7.6
- [Qemu-devel] [PATCH v2 04/18] block: non-raw protocols never cache, (continued)
- [Qemu-devel] [PATCH v2 04/18] block: non-raw protocols never cache, Paolo Bonzini, 2012/01/26
- [Qemu-devel] [PATCH v2 05/18] block: remove enable_write_cache, Paolo Bonzini, 2012/01/26
- [Qemu-devel] [PATCH v2 06/18] block: move flag bits together, Paolo Bonzini, 2012/01/26
- [Qemu-devel] [PATCH v2 07/18] raw: remove the aligned_buf, Paolo Bonzini, 2012/01/26
- [Qemu-devel] [PATCH v2 09/18] block: add host_block_size, Paolo Bonzini, 2012/01/26
- [Qemu-devel] [PATCH v2 11/18] iscsi: save host block size, Paolo Bonzini, 2012/01/26
- [Qemu-devel] [PATCH v2 08/18] block: rename buffer_alignment to guest_block_size, Paolo Bonzini, 2012/01/26
- [Qemu-devel] [PATCH v2 10/18] raw: probe host_block_size, Paolo Bonzini, 2012/01/26
- [Qemu-devel] [PATCH v2 12/18] block: allow waiting only for overlapping writes, Paolo Bonzini, 2012/01/26
- [Qemu-devel] [PATCH v2 14/18] block: protect against "torn reads" for guest_block_size > host_block_size, Paolo Bonzini, 2012/01/26
- [Qemu-devel] [PATCH v2 17/18] block: default min_io_size to host block size when doing rmw,
Paolo Bonzini <=
- [Qemu-devel] [PATCH v2 16/18] block: default physical block size to host block size, Paolo Bonzini, 2012/01/26
- [Qemu-devel] [PATCH v2 18/18] qemu-io: add blocksize argument to open, Paolo Bonzini, 2012/01/26
- [Qemu-devel] [PATCH v2 15/18] block: align and serialize I/O when guest_block_size < host_block_size, Paolo Bonzini, 2012/01/26
- [Qemu-devel] [PATCH v2 13/18] block: allow waiting at arbitrary granularity, Paolo Bonzini, 2012/01/26