[lvm-devel] LVM2 ./WHATS_NEW doc/example.conf lib/config/d ...
snitzer at sourceware.org
snitzer at sourceware.org
Sat Aug 1 17:08:45 UTC 2009
CVSROOT: /cvs/lvm2
Module name: LVM2
Changes by: snitzer at sourceware.org 2009-08-01 17:08:44
Modified files:
. : WHATS_NEW
doc : example.conf
lib/config : defaults.h
lib/device : device.c device.h
lib/metadata : metadata.c
man : lvm.conf.5.in
Log message:
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 âminimum_io_sizeâ or âoptimal_io_sizeâ
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 at redhat.com>
Patches:
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/WHATS_NEW.diff?cvsroot=lvm2&r1=1.1224&r2=1.1225
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/doc/example.conf.diff?cvsroot=lvm2&r1=1.43&r2=1.44
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/lib/config/defaults.h.diff?cvsroot=lvm2&r1=1.48&r2=1.49
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/lib/device/device.c.diff?cvsroot=lvm2&r1=1.28&r2=1.29
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/lib/device/device.h.diff?cvsroot=lvm2&r1=1.41&r2=1.42
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/lib/metadata/metadata.c.diff?cvsroot=lvm2&r1=1.276&r2=1.277
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/man/lvm.conf.5.in.diff?cvsroot=lvm2&r1=1.5&r2=1.6
--- LVM2/WHATS_NEW 2009/08/01 17:07:36 1.1224
+++ LVM2/WHATS_NEW 2009/08/01 17:08:43 1.1225
@@ -4,6 +4,7 @@
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.
--- LVM2/doc/example.conf 2009/08/01 17:07:36 1.43
+++ LVM2/doc/example.conf 2009/08/01 17:08:44 1.44
@@ -98,9 +98,21 @@
# 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
--- LVM2/lib/config/defaults.h 2009/08/01 17:07:37 1.48
+++ LVM2/lib/config/defaults.h 2009/08/01 17:08:44 1.49
@@ -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"
--- LVM2/lib/device/device.c 2009/08/01 17:07:37 1.28
+++ LVM2/lib/device/device.c 2009/08/01 17:08:44 1.29
@@ -285,13 +285,36 @@
#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 @@
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 @@
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 @@
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
--- LVM2/lib/device/device.h 2009/08/01 17:07:37 1.41
+++ LVM2/lib/device/device.h 2009/08/01 17:08:44 1.42
@@ -103,4 +103,10 @@
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
--- LVM2/lib/metadata/metadata.c 2009/08/01 17:07:37 1.276
+++ LVM2/lib/metadata/metadata.c 2009/08/01 17:08:44 1.277
@@ -86,6 +86,25 @@
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);
--- LVM2/man/lvm.conf.5.in 2009/08/01 17:07:37 1.5
+++ LVM2/man/lvm.conf.5.in 2009/08/01 17:08:44 1.6
@@ -137,11 +137,23 @@
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 âminimum_io_sizeâ or
+âoptimal_io_sizeâ 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
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