[PATCH 1 of 3] block: Export I/O hints for block devices and partitions | |
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3 files changed, 74 insertions(+)
block/genhd.c | 39 +++++++++++++++++++++++++++++++++++++++
fs/partitions/check.c | 11 +++++++++++
include/linux/genhd.h | 24 ++++++++++++++++++++++++
Export physical start offset and preferred I/O sizes in sysfs. This
allows filesystems to align data structures to RAID stripes.
`physical offset' indicates the physical offset in sectors to the
start of the block device.
`optimal_io_block' indicates the smallest request that can be
submitted without incurring a performance penalty (RAID
read-modify-write, 512-byte sector emulation). It is recommended that
I/O requests are a multiple of this size.
`optimal-io-length' indicates the optimal I/O length for the device
(i.e. stripe size).
These values are largely modeled after the SCSI SBC-3 Block Limits
VPD.
Block device drivers may call disk_set_io_hints() to set these values
to their preference.
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
---
diff -r 3e197642edae -r 3e5d8520d247 block/genhd.c
--- a/block/genhd.c Mon Jun 02 15:30:44 2008 -0700
+++ b/block/genhd.c Thu Jun 05 01:07:51 2008 -0400
@@ -222,6 +222,15 @@
return kobj ? dev_to_disk(dev) : NULL;
}
+void disk_set_io_hints(struct gendisk *disk, sector_t offset, uint block, uint len)
+{
+ printk(KERN_ERR "%s I/O hints: off %llu, gran %u, len %u\n",
+ disk->disk_name, (unsigned long long)offset, block, len);
+ disk->phys_offset = offset;
+ disk->optimal_io_block = block;
+ disk->optimal_io_length = len;
+}
+
/*
* print a full list of all partitions - intended for places where the root
* filesystem can't be mounted and thus to give the victim some idea of what
@@ -416,6 +425,30 @@
return sprintf(buf, "%x\n", disk->flags);
}
+static ssize_t disk_phys_offset_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct gendisk *disk = dev_to_disk(dev);
+
+ return sprintf(buf, "%llu\n", (unsigned long long)disk->phys_offset);
+}
+
+static ssize_t disk_optimal_io_block_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct gendisk *disk = dev_to_disk(dev);
+
+ return sprintf(buf, "%u\n", disk->optimal_io_block);
+}
+
+static ssize_t disk_optimal_io_length_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct gendisk *disk = dev_to_disk(dev);
+
+ return sprintf(buf, "%u\n", disk->optimal_io_length);
+}
+
static ssize_t disk_stat_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
@@ -474,6 +507,9 @@
static DEVICE_ATTR(removable, S_IRUGO, disk_removable_show, NULL);
static DEVICE_ATTR(size, S_IRUGO, disk_size_show, NULL);
static DEVICE_ATTR(capability, S_IRUGO, disk_capability_show, NULL);
+static DEVICE_ATTR(phys_offset, S_IRUGO, disk_phys_offset_show, NULL);
+static DEVICE_ATTR(optimal_io_block, S_IRUGO, disk_optimal_io_block_show, NULL);
+static DEVICE_ATTR(optimal_io_length, S_IRUGO, disk_optimal_io_length_show, NULL);
static DEVICE_ATTR(stat, S_IRUGO, disk_stat_show, NULL);
#ifdef CONFIG_FAIL_MAKE_REQUEST
static struct device_attribute dev_attr_fail =
@@ -485,6 +521,9 @@
&dev_attr_removable.attr,
&dev_attr_size.attr,
&dev_attr_capability.attr,
+ &dev_attr_phys_offset.attr,
+ &dev_attr_optimal_io_block.attr,
+ &dev_attr_optimal_io_length.attr,
&dev_attr_stat.attr,
#ifdef CONFIG_FAIL_MAKE_REQUEST
&dev_attr_fail.attr,
diff -r 3e197642edae -r 3e5d8520d247 fs/partitions/check.c
--- a/fs/partitions/check.c Mon Jun 02 15:30:44 2008 -0700
+++ b/fs/partitions/check.c Thu Jun 05 01:07:51 2008 -0400
@@ -204,6 +204,14 @@
return sprintf(buf, "%llu\n",(unsigned long long)p->start_sect);
}
+static ssize_t part_phys_offset_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct hd_struct *p = dev_to_part(dev);
+
+ return sprintf(buf, "%llu\n",(unsigned long long)p->phys_offset);
+}
+
static ssize_t part_size_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
@@ -261,6 +269,7 @@
#endif
static DEVICE_ATTR(start, S_IRUGO, part_start_show, NULL);
+static DEVICE_ATTR(phys_offset, S_IRUGO, part_phys_offset_show, NULL);
static DEVICE_ATTR(size, S_IRUGO, part_size_show, NULL);
static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL);
#ifdef CONFIG_FAIL_MAKE_REQUEST
@@ -271,6 +280,7 @@
static struct attribute *part_attrs[] = {
&dev_attr_start.attr,
&dev_attr_size.attr,
+ &dev_attr_phys_offset.attr,
&dev_attr_stat.attr,
#ifdef CONFIG_FAIL_MAKE_REQUEST
&dev_attr_fail.attr,
@@ -358,6 +368,7 @@
return;
}
p->start_sect = start;
+ p->phys_offset = disk->phys_offset + start;
p->nr_sects = len;
p->partno = part;
p->policy = disk->policy;
diff -r 3e197642edae -r 3e5d8520d247 include/linux/genhd.h
--- a/include/linux/genhd.h Mon Jun 02 15:30:44 2008 -0700
+++ b/include/linux/genhd.h Thu Jun 05 01:07:51 2008 -0400
@@ -87,6 +87,7 @@
struct hd_struct {
sector_t start_sect;
sector_t nr_sects;
+ sector_t phys_offset;
struct device dev;
struct kobject *holder_dir;
int policy, partno;
@@ -122,6 +123,10 @@
struct request_queue *queue;
void *private_data;
sector_t capacity;
+
+ sector_t phys_offset;
+ unsigned int optimal_io_block;
+ unsigned int optimal_io_length;
int flags;
struct device *driverfs_dev; // FIXME: remove
@@ -357,6 +362,25 @@
extern void del_gendisk(struct gendisk *gp);
extern void unlink_gendisk(struct gendisk *gp);
extern struct gendisk *get_gendisk(dev_t dev, int *part);
+extern void disk_set_io_hints(struct gendisk *, sector_t, unsigned int, unsigned int);
+
+static inline sector_t bdev_phys_offset(struct block_device *bdev)
+{
+ if (bdev != bdev->bd_contains)
+ return bdev->bd_part->phys_offset;
+
+ return bdev->bd_disk->phys_offset;
+}
+
+static inline unsigned int bdev_optimal_io_block(struct block_device *bdev)
+{
+ return bdev->bd_disk->optimal_io_block;
+}
+
+static inline unsigned int bdev_optimal_io_length(struct block_device *bdev)
+{
+ return bdev->bd_disk->optimal_io_length;
+}
extern void set_device_ro(struct block_device *bdev, int flag);
extern void set_disk_ro(struct gendisk *disk, int flag);
--
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