1
0
mirror of git://sourceware.org/git/lvm2.git synced 2025-02-06 01:58:01 +03:00

Add devices/data_alignment_detection to lvm.conf.

Adds 'data_alignment_detection' config option to the devices section of
lvm.conf.  If your kernel provides topology information in sysfs (linux
>= 2.6.31) for the Physical Volume, the start of data area will be
aligned on a multiple of the ’minimum_io_size’ or ’optimal_io_size’
exposed in sysfs.

minimum_io_size is used if optimal_io_size is undefined (0).  If both
md_chunk_alignment and data_alignment_detection are enabled the result
of data_alignment_detection is used.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Mike Snitzer 2009-08-01 17:08:43 +00:00
parent 57b660356e
commit 2aabcc1c1c
7 changed files with 125 additions and 9 deletions

View File

@ -4,6 +4,7 @@ Version 2.02.51 -
Added configure --enable-udev_rules --enable-udev_sync.
Added configure --with-udev-prefix --with-udevdir.
Added udev dir to hold udev rules.
Add devices/data_alignment_detection to lvm.conf.
Add devices/data_alignment_offset_detection to lvm.conf.
Add --dataalignmentoffset to pvcreate to shift start of aligned data area.
Fix _mda_setup() to not check first mda's size before pe_align rounding.

View File

@ -98,9 +98,21 @@ devices {
# 1 enables; 0 disables.
md_chunk_alignment = 1
# By default, the start of a PV's data area will be a multiple of
# the 'minimum_io_size' or 'optimal_io_size' exposed in sysfs.
# - minimum_io_size - the smallest request the device can perform
# w/o incurring a read-modify-write penalty (e.g. MD's chunk size)
# - optimal_io_size - the device's preferred unit of receiving I/O
# (e.g. MD's stripe width)
# minimum_io_size is used if optimal_io_size is undefined (0).
# If md_chunk_alignment is enabled, that detects the optimal_io_size.
# This setting takes precedence over md_chunk_alignment.
# 1 enables; 0 disables.
data_alignment_detection = 1
# Alignment (in KB) of start of data area when creating a new PV.
# If a PV is placed directly upon an md device and md_chunk_alignment is
# enabled this parameter is ignored.
# If a PV is placed directly upon an md device and md_chunk_alignment or
# data_alignment_detection is enabled this parameter is ignored.
# Set to 0 for the default alignment of 64KB or page size, if larger.
data_alignment = 0

View File

@ -35,6 +35,7 @@
#define DEFAULT_MD_CHUNK_ALIGNMENT 1
#define DEFAULT_IGNORE_SUSPENDED_DEVICES 1
#define DEFAULT_DATA_ALIGNMENT_OFFSET_DETECTION 1
#define DEFAULT_DATA_ALIGNMENT_DETECTION 1
#define DEFAULT_LOCK_DIR "/var/lock/lvm"
#define DEFAULT_LOCKING_LIB "liblvm2clusterlock.so"

View File

@ -285,13 +285,36 @@ int _get_partition_type(struct dev_mgr *dm, struct device *d)
#ifdef linux
static int _primary_dev(const char *sysfs_dir,
struct device *dev, dev_t *result)
{
char path[PATH_MAX+1];
struct stat info;
/* check if dev is a partition */
if (dm_snprintf(path, PATH_MAX, "%s/dev/block/%d:%d/partition",
sysfs_dir, (int)MAJOR(dev->dev), (int)MINOR(dev->dev)) < 0) {
log_error("dm_snprintf partition failed");
return 0;
}
if (stat(path, &info) < 0)
return 0;
*result = dev->dev -
(MINOR(dev->dev) % max_partitions(MAJOR(dev->dev)));
return 1;
}
static unsigned long _dev_topology_attribute(const char *attribute,
const char *sysfs_dir,
struct device *dev)
{
const char *sysfs_fmt_str = "%s/dev/block/%d:%d/%s";
char path[PATH_MAX+1], buffer[64];
FILE *fp;
struct stat info;
dev_t uninitialized_var(primary);
unsigned long result = 0UL;
if (!attribute || !*attribute)
@ -300,16 +323,32 @@ static unsigned long _dev_topology_attribute(const char *attribute,
if (!sysfs_dir || !*sysfs_dir)
return_0;
if (dm_snprintf(path, PATH_MAX, "%s/dev/block/%d:%d/%s",
sysfs_dir, (int)MAJOR(dev->dev), (int)MINOR(dev->dev),
if (dm_snprintf(path, PATH_MAX, sysfs_fmt_str, sysfs_dir,
(int)MAJOR(dev->dev), (int)MINOR(dev->dev),
attribute) < 0) {
log_error("dm_snprintf %s failed", attribute);
return 0;
}
/* check if the desired sysfs attribute exists */
if (stat(path, &info) < 0)
return 0;
/*
* check if the desired sysfs attribute exists
* - if not: either the kernel doesn't have topology support
* or the device could be a partition
*/
if (stat(path, &info) < 0) {
if (!_primary_dev(sysfs_dir, dev, &primary))
return 0;
/* get attribute from partition's primary device */
if (dm_snprintf(path, PATH_MAX, sysfs_fmt_str, sysfs_dir,
(int)MAJOR(primary), (int)MINOR(primary),
attribute) < 0) {
log_error("primary dm_snprintf %s failed", attribute);
return 0;
}
if (stat(path, &info) < 0)
return 0;
}
if (!(fp = fopen(path, "r"))) {
log_sys_error("fopen", path);
@ -344,6 +383,20 @@ unsigned long dev_alignment_offset(const char *sysfs_dir,
sysfs_dir, dev);
}
unsigned long dev_minimum_io_size(const char *sysfs_dir,
struct device *dev)
{
return _dev_topology_attribute("queue/minimum_io_size",
sysfs_dir, dev);
}
unsigned long dev_optimal_io_size(const char *sysfs_dir,
struct device *dev)
{
return _dev_topology_attribute("queue/optimal_io_size",
sysfs_dir, dev);
}
#else
unsigned long dev_alignment_offset(const char *sysfs_dir,
@ -352,4 +405,16 @@ unsigned long dev_alignment_offset(const char *sysfs_dir,
return 0UL;
}
unsigned long dev_minimum_io_size(const char *sysfs_dir,
struct device *dev)
{
return 0UL;
}
unsigned long dev_optimal_io_size(const char *sysfs_dir,
struct device *dev)
{
return 0UL;
}
#endif

View File

@ -103,4 +103,10 @@ int is_partitioned_dev(struct device *dev);
unsigned long dev_alignment_offset(const char *sysfs_dir,
struct device *dev);
unsigned long dev_minimum_io_size(const char *sysfs_dir,
struct device *dev);
unsigned long dev_optimal_io_size(const char *sysfs_dir,
struct device *dev);
#endif

View File

@ -86,6 +86,25 @@ unsigned long set_pe_align(struct physical_volume *pv, unsigned long data_alignm
dev_md_stripe_width(pv->fmt->cmd->sysfs_dir,
pv->dev));
/*
* Align to topology's minimum_io_size or optimal_io_size if present
* - minimum_io_size - the smallest request the device can perform
* w/o incurring a read-modify-write penalty (e.g. MD's chunk size)
* - optimal_io_size - the device's preferred unit of receiving I/O
* (e.g. MD's stripe width)
*/
if (find_config_tree_bool(pv->fmt->cmd,
"devices/data_alignment_detection",
DEFAULT_DATA_ALIGNMENT_DETECTION)) {
pv->pe_align = MAX(pv->pe_align,
dev_minimum_io_size(pv->fmt->cmd->sysfs_dir,
pv->dev));
pv->pe_align = MAX(pv->pe_align,
dev_optimal_io_size(pv->fmt->cmd->sysfs_dir,
pv->dev));
}
log_very_verbose("%s: Setting PE alignment to %lu sectors.",
dev_name(pv->dev), pv->pe_align);

View File

@ -137,11 +137,23 @@ has been reused without wiping the md superblocks first.
directly upon an md device, LVM2 will align its data blocks with the
md device's stripe-width.
.IP
\fBdata_alignment_detection\fP \(em If set to 1, and your kernel provides
topology information in sysfs for the Physical Volume, the start of data
area will be aligned on a multiple of the minimum_io_size or
optimal_io_size exposed in sysfs. minimum_io_size is the smallest
request the device can perform without incurring a read-modify-write
penalty (e.g. MD's chunk size). optimal_io_size is the device's
preferred unit of receiving I/O (e.g. MD's stripe width). minimum_io_size
is used if optimal_io_size is undefined (0). If both \fBmd_chunk_alignment\fP
and \fBdata_alignment_detection\fP are enabled the result of
\fBdata_alignment_detection\fP is used.
.IP
\fBdata_alignment\fP \(em Default alignment (in KB) of start of data area
when creating a new Physical Volume using the \fBlvm2\fP format.
If a Physical Volume is placed directly upon an md device and
\fBmd_chunk_alignment\fP is enabled this parameter is ignored.
Set to 0 to use the default alignment of 64KB or the page size, if larger.
\fBmd_chunk_alignment\fP or \fBdata_alignment_detection\fP is enabled
this parameter is ignored. Set to 0 to use the default alignment of
64KB or the page size, if larger.
.IP
\fBdata_alignment_offset_detection\fP \(em If set to 1, and your kernel
provides topology information in sysfs for the Physical Volume, the