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[Qemu-devel] [PATCH 4/5] blockdev: enable discard by default
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PATCH 4/5] blockdev: enable discard by default |
Date: |
Fri, 8 Feb 2013 14:06:14 +0100 |
Because discard is now a host parameter, we can always fake it as enabled
in the guest. This is an extension of the current choice to ignore
"not supported" errors from the host when discard_granularity is set
to nonzero.
The default granularity is set to the logical block size or 4k, whichever
is largest, because cluster sizes below 4k are rarely used and 4K is a
typical block size for files.
Signed-off-by: Paolo Bonzini <address@hidden>
---
hw/block-common.h | 2 +-
hw/ide/qdev.c | 5 ++++-
hw/scsi-disk.c | 13 ++++++++++---
3 files changed, 15 insertions(+), 5 deletions(-)
diff --git a/hw/block-common.h b/hw/block-common.h
index bb808f7..dd11532 100644
--- a/hw/block-common.h
+++ b/hw/block-common.h
@@ -50,7 +50,7 @@ static inline unsigned int get_physical_block_exp(BlockConf
*conf)
DEFINE_PROP_UINT32("opt_io_size", _state, _conf.opt_io_size, 0), \
DEFINE_PROP_INT32("bootindex", _state, _conf.bootindex, -1), \
DEFINE_PROP_UINT32("discard_granularity", _state, \
- _conf.discard_granularity, 0)
+ _conf.discard_granularity, -1)
#define DEFINE_BLOCK_CHS_PROPERTIES(_state, _conf) \
DEFINE_PROP_UINT32("cyls", _state, _conf.cyls, 0), \
diff --git a/hw/ide/qdev.c b/hw/ide/qdev.c
index c436b38..fd06da7 100644
--- a/hw/ide/qdev.c
+++ b/hw/ide/qdev.c
@@ -143,7 +143,10 @@ static int ide_dev_initfn(IDEDevice *dev, IDEDriveKind
kind)
IDEBus *bus = DO_UPCAST(IDEBus, qbus, dev->qdev.parent_bus);
IDEState *s = bus->ifs + dev->unit;
- if (dev->conf.discard_granularity && dev->conf.discard_granularity != 512)
{
+ if (dev->conf.discard_granularity == -1) {
+ dev->conf.discard_granularity = 512;
+ } else if (dev->conf.discard_granularity &&
+ dev->conf.discard_granularity != 512) {
error_report("discard_granularity must be 512 for ide");
return -1;
}
diff --git a/hw/scsi-disk.c b/hw/scsi-disk.c
index 28e75bb..e11a5bb 100644
--- a/hw/scsi-disk.c
+++ b/hw/scsi-disk.c
@@ -41,9 +41,11 @@ do { printf("scsi-disk: " fmt , ## __VA_ARGS__); } while (0)
#include <scsi/sg.h>
#endif
-#define SCSI_DMA_BUF_SIZE 131072
-#define SCSI_MAX_INQUIRY_LEN 256
-#define SCSI_MAX_MODE_LEN 256
+#define SCSI_DMA_BUF_SIZE 131072
+#define SCSI_MAX_INQUIRY_LEN 256
+#define SCSI_MAX_MODE_LEN 256
+
+#define DEFAULT_DISCARD_GRANULARITY 4096
typedef struct SCSIDiskState SCSIDiskState;
@@ -2059,6 +2061,11 @@ static int scsi_initfn(SCSIDevice *dev)
return -1;
}
+ if (s->qdev.conf.discard_granularity == -1) {
+ s->qdev.conf.discard_granularity =
+ MAX(s->qdev.conf.logical_block_size, DEFAULT_DISCARD_GRANULARITY);
+ }
+
if (!s->version) {
s->version = g_strdup(qemu_get_version());
}
--
1.8.1.2
- [Qemu-devel] [RFC PATCH 0/5] Make discard visible to the guests, Paolo Bonzini, 2013/02/08
- [Qemu-devel] [PATCH 1/5] block: implement BDRV_O_UNMAP, Paolo Bonzini, 2013/02/08
- [Qemu-devel] [PATCH 2/5] blockdev: add discard suboption to -drive, Paolo Bonzini, 2013/02/08
- [Qemu-devel] [PATCH 3/5] qemu-nbd: add --discard option, Paolo Bonzini, 2013/02/08
- [Qemu-devel] [PATCH 5/5] pc: add compatibility machine types for 1.4, Paolo Bonzini, 2013/02/08
- [Qemu-devel] [PATCH 4/5] blockdev: enable discard by default,
Paolo Bonzini <=
- Re: [Qemu-devel] [RFC PATCH 0/5] Make discard visible to the guests, Stefan Hajnoczi, 2013/02/13