c/mirror_zfs
1
0
Fork 0
mirror of https://git.proxmox.com/git/mirror_zfs.git synced 2024-12-26 03:09:34 +03:00
Code Issues Packages Projects Releases Wiki Activity
a5c20e2a0a
mirror_zfs/module/zfs
History
Etienne Dechamps a5c20e2a0a Don't ashift-align vdev read requests. 
Currently, the size of read and write requests on vdevs is aligned
according to the vdev's ashift, allocating a new ZIO buffer and padding
if need be.

This makes sense for write requests to prevent read/modify/write if the
write happens to be smaller than the device's internal block size.

For reads however, the rationale is less clear. It seems that the
original code aligns reads because, on Solaris, device drivers will
outright refuse unaligned requests.

We don't have that issue on Linux. Indeed, Linux block devices are able
to accept requests of any size, and take care of alignment issues
themselves.

As a result, there's no point in enforcing alignment for read requests
on Linux. This is a nice optimization opportunity for two reasons:
- We remove a memory allocation in a heavily-used code path;
- The request gets aligned in the lowest layer possible, which shrinks
  the path that the additional, useless padding data has to travel.
  For example, when using 4k-sector drives that lie about their sector
  size, using 512b read requests instead of 4k means that there will
  be less data traveling down the ATA/SCSI interface, even though the
  drive actually reads 4k from the platter.

The only exception is raidz, because raidz needs to read the whole
allocated block for parity.

This patch removes alignment enforcement for read requests, except on
raidz. Note that we also remove an assertion that checks that we're
aligning a top-level vdev I/O, because that's not the case anymore for
repair writes that results from failed reads.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1022
2012-10-12 12:01:56 -07:00
..
arc.c Remove vmem_size() consumers 2012-10-12 10:03:03 -07:00
bplist.c Switch KM_SLEEP to KM_PUSHPAGE 2012-08-27 12:01:37 -07:00
bpobj.c Illumos #1644, #1645, #1646, #1647, #1708 2012-07-31 09:25:30 -07:00
dbuf.c Switch KM_SLEEP to KM_PUSHPAGE 2012-08-27 12:01:37 -07:00
ddt_zap.c Switch KM_SLEEP to KM_PUSHPAGE 2012-10-04 10:44:09 -07:00
ddt.c Switch KM_SLEEP to KM_PUSHPAGE 2012-09-19 11:52:36 -07:00
dmu_diff.c Update to onnv_147 2010-08-26 14:24:34 -07:00
dmu_object.c Add linux kernel module support 2010-08-31 13:41:58 -07:00
dmu_objset.c Switch KM_SLEEP to KM_PUSHPAGE 2012-10-08 10:19:05 -07:00
dmu_send.c Illumos #2703: add mechanism to report ZFS send progress 2012-09-19 13:39:06 -07:00
dmu_traverse.c Switch KM_SLEEP to KM_PUSHPAGE 2012-08-27 12:01:37 -07:00
dmu_tx.c Switch KM_SLEEP to KM_PUSHPAGE 2012-08-27 12:01:37 -07:00
dmu_zfetch.c Switch KM_SLEEP to KM_PUSHPAGE 2012-08-27 12:01:37 -07:00
dmu.c Switch KM_SLEEP to KM_PUSHPAGE 2012-08-27 12:01:37 -07:00
dnode_sync.c Fix dbuf eviction assertion 2010-08-31 08:38:45 -07:00
dnode.c Switch KM_SLEEP to KM_PUSHPAGE 2012-08-27 12:01:37 -07:00
dsl_dataset.c Illumos #3100: zvol rename fails with EBUSY when dirty. 2012-10-03 13:59:02 -07:00
dsl_deadlist.c Switch KM_SLEEP to KM_PUSHPAGE 2012-08-27 12:01:37 -07:00
dsl_deleg.c Illumos #1644, #1645, #1646, #1647, #1708 2012-07-31 09:25:30 -07:00
dsl_dir.c Illumos #3100: zvol rename fails with EBUSY when dirty. 2012-10-03 13:59:02 -07:00
dsl_pool.c txg is spelled as tgx in places 2012-10-11 09:19:08 -07:00
dsl_prop.c Switch KM_SLEEP to KM_PUSHPAGE 2012-09-17 11:22:23 -07:00
dsl_scan.c Fix zfs_txg_timeout module parameter 2012-10-11 15:07:09 -07:00
dsl_synctask.c Add linux kernel module support 2010-08-31 13:41:58 -07:00
fm.c Switch KM_SLEEP to KM_PUSHPAGE 2012-09-02 10:15:49 -07:00
gzip.c Fix zmod.h usage in userspace 2010-08-31 08:38:46 -07:00
lzjb.c Switch KM_SLEEP to KM_PUSHPAGE 2012-08-27 12:01:37 -07:00
Makefile.in Add script for builtin module building. 2012-07-26 13:45:09 -07:00
metaslab.c Switch KM_SLEEP to KM_PUSHPAGE 2012-08-27 12:01:37 -07:00
refcount.c Switch KM_SLEEP to KM_PUSHPAGE 2012-08-27 12:01:37 -07:00
rrwlock.c Enable rrwlock.c compilation 2010-12-07 16:05:25 -08:00
sa.c Switch KM_SLEEP to KM_PUSHPAGE 2012-08-27 12:01:37 -07:00
sha256.c Add linux sha2 support 2010-08-31 13:41:59 -07:00
spa_boot.c Add linux kernel module support 2010-08-31 13:41:58 -07:00
spa_config.c Switch KM_SLEEP to KM_PUSHPAGE 2012-08-27 12:01:37 -07:00
spa_errlog.c Add linux kernel module support 2010-08-31 13:41:58 -07:00
spa_history.c Switch KM_SLEEP to KM_PUSHPAGE 2012-08-27 12:01:37 -07:00
spa_misc.c Switch KM_SLEEP to KM_PUSHPAGE 2012-08-27 12:01:37 -07:00
spa.c Illumos #1948: zpool list should show more detailed pool info 2012-09-19 13:39:05 -07:00
space_map.c Switch KM_SLEEP to KM_PUSHPAGE 2012-08-27 12:01:37 -07:00
txg.c Fix zfs_txg_timeout module parameter 2012-10-11 15:07:09 -07:00
uberblock.c Update core ZFS code from build 121 to build 141. 2010-05-28 13:45:14 -07:00
unique.c Switch KM_SLEEP to KM_PUSHPAGE 2012-08-27 12:01:37 -07:00
vdev_cache.c Switch KM_SLEEP to KM_PUSHPAGE 2012-08-27 12:01:37 -07:00
vdev_disk.c Modify vdev_elevator_switch() to use elevator_change() 2012-10-03 13:31:44 -07:00
vdev_file.c Illumos #1948: zpool list should show more detailed pool info 2012-09-19 13:39:05 -07:00
vdev_label.c Switch KM_SLEEP to KM_PUSHPAGE 2012-08-27 12:01:37 -07:00
vdev_mirror.c Illumos #1948: zpool list should show more detailed pool info 2012-09-19 13:39:05 -07:00
vdev_missing.c Illumos #1948: zpool list should show more detailed pool info 2012-09-19 13:39:05 -07:00
vdev_queue.c Pre-allocate vdev I/O buffers 2012-08-27 12:01:37 -07:00
vdev_raidz.c Illumos #1948: zpool list should show more detailed pool info 2012-09-19 13:39:05 -07:00
vdev_root.c Illumos #1948: zpool list should show more detailed pool info 2012-09-19 13:39:05 -07:00
vdev.c Illumos #1948: zpool list should show more detailed pool info 2012-09-19 13:39:05 -07:00
zap_leaf.c Switch KM_SLEEP to KM_PUSHPAGE 2012-09-05 08:44:58 -07:00
zap_micro.c Switch KM_SLEEP to KM_PUSHPAGE 2012-09-05 08:44:58 -07:00
zap.c Switch KM_SLEEP to KM_PUSHPAGE 2012-08-27 12:01:37 -07:00
zfs_acl.c Switch KM_SLEEP to KM_PUSHPAGE 2012-08-27 12:01:37 -07:00
zfs_byteswap.c Add linux kernel module support 2010-08-31 13:41:58 -07:00
zfs_ctldir.c Disable .zfs directory on 32-bit systems 2012-07-20 12:20:57 -07:00
zfs_debug.c Use spl_debug_* helpers 2012-02-09 16:37:48 -08:00
zfs_dir.c rmdir(2) should return ENOTEMPTY 2012-08-26 13:55:45 -07:00
zfs_fm.c Switch KM_SLEEP to KM_PUSHPAGE 2012-08-27 12:01:37 -07:00
zfs_fuid.c Drop HAVE_XVATTR macros 2011-03-02 11:44:34 -08:00
zfs_ioctl.c Illumos #3129, #3130 2012-10-03 13:59:02 -07:00
zfs_log.c Make zfs_immediate_write_sz a module paramater 2012-10-11 11:09:21 -07:00
zfs_onexit.c Add linux kernel device support 2010-08-31 13:41:50 -07:00
zfs_replay.c ZFS replay transaction error 5 2012-09-17 11:06:58 -07:00
zfs_rlock.c Switch KM_SLEEP to KM_PUSHPAGE 2012-08-27 12:01:37 -07:00
zfs_sa.c Revert "Use SA_HDL_PRIVATE for SA xattrs" 2012-08-25 09:25:56 -07:00
zfs_vfsops.c Illumos #3100: zvol rename fails with EBUSY when dirty. 2012-10-03 13:59:02 -07:00
zfs_vnops.c Clear PG_writeback for sync I/O error case 2012-09-14 15:53:47 -07:00
zfs_znode.c Switch KM_SLEEP to KM_PUSHPAGE 2012-08-27 12:01:37 -07:00
zil.c Switch KM_SLEEP to KM_PUSHPAGE 2012-08-27 12:01:37 -07:00
zio_checksum.c Update core ZFS code from build 121 to build 141. 2010-05-28 13:45:14 -07:00
zio_compress.c Update core ZFS code from build 121 to build 141. 2010-05-28 13:45:14 -07:00
zio_inject.c Add missing ZFS tunables 2011-05-04 10:02:37 -07:00
zio.c Don't ashift-align vdev read requests. 2012-10-12 12:01:56 -07:00
zle.c Update core ZFS code from build 121 to build 141. 2010-05-28 13:45:14 -07:00
zpl_ctldir.c Linux 3.3 compat, iops->create()/mkdir()/mknod() 2012-04-30 12:52:38 -07:00
zpl_export.c Implement .commit_metadata hook for NFS export 2012-10-03 10:49:45 -07:00
zpl_file.c Annotate KM_PUSHPAGE call paths with PF_NOFS 2012-08-27 12:01:37 -07:00
zpl_inode.c Linux 3.5 compat, iops->truncate_range() removed 2012-07-23 12:29:32 -07:00
zpl_super.c Linux 3.5 compat, end_writeback() changed to clear_inode() 2012-07-23 12:29:36 -07:00
zpl_xattr.c Add missing NULL in zpl_xattr_handlers 2012-03-15 15:18:29 -07:00
zrlock.c Export ZFS symbols needed by Lustre. 2010-09-17 16:24:15 -07:00
zvol.c Set default zvol elevator to noop 2012-10-05 12:39:59 -07:00