linux.git/drivers/md/raid10.c, branch v2.6.15

[PATCH] md: improve read speed to raid10 arrays using 'far copies'

2005-11-28T22:42:25+00:00

raid10 has two different layouts.  One uses near-copies (so multiple
copies of a block are at the same or similar offsets of different
devices) and the other uses far-copies (so multiple copies of a block
are stored a greatly different offsets on different devices).  The point
of far-copies is that it allows the first section (normally first half)
to be layed out in normal raid0 style, and thus provide raid0 sequential
read performance.

Unfortunately, the read balancing in raid10 makes some poor decisions
for far-copies arrays and you don't get the desired performance.  So
turn off that bad bit of read_balance for far-copies arrays.

With this patch, read speed of an 'f2' array is comparable with a raid0
with the same number of devices, though write speed is ofcourse still
very slow.

Signed-off-by: Neil Brown 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] md: convert 'faulty' and 'in_sync' fields to bits in 'flags' field

2005-11-09T15:56:38+00:00

This has the advantage of removing the confusion caused by 'rdev_t' and
'mddev_t' both having 'in_sync' fields.

Signed-off-by: Neil Brown 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] md: provide proper rcu_dereference / rcu_assign_pointer annotations in md

2005-11-09T15:56:37+00:00

Acked-by: 
Signed-off-by: Suzanne Wood 
Signed-off-by: Neil Brown 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[BLOCK] Unify the seperate read/write io stat fields into arrays

2005-11-01T08:26:16+00:00

Instead of having ->read_sectors and ->write_sectors, combine the two
into ->sectors[2] and similar for the other fields. This saves a branch
several places in the io path, since we don't have to care for what the
actual io direction is. On my x86-64 box, that's 200 bytes less text in
just the core (not counting the various drivers).

Signed-off-by: Jens Axboe

[PATCH] gfp flags annotations - part 1

2005-10-08T22:00:57+00:00

 - added typedef unsigned int __nocast gfp_t;

 - replaced __nocast uses for gfp flags with gfp_t - it gives exactly
   the same warnings as far as sparse is concerned, doesn't change
   generated code (from gcc point of view we replaced unsigned int with
   typedef) and documents what's going on far better.

Signed-off-by: Al Viro 
Signed-off-by: Linus Torvalds

[PATCH] md: fix BUG when raid10 rebuilds without enough drives

2005-09-09T23:39:15+00:00

This shouldn't be a BUG.  We should cope.

Signed-off-by: Neil Brown 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] md: fix raid10 assembly when too many devices are missing

2005-09-09T23:39:14+00:00

If you try to assemble an array with too many missing devices, raid10 will now
reject the attempt, instead of allowing it.

Also check when hot-adding a drive and refuse the hot-add if the array is
beyond hope.

Signed-off-by: Neil Brown 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] md: fail IO request to md that require a barrier.

2005-09-09T23:39:09+00:00

md does not yet support BIO_RW_BARRIER, so be honest about it and fail
(-EOPNOTSUPP) any such requests.

Signed-off-by: Neil Brown 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] md: fix minor error in raid10 read-balancing calculation.

2005-09-09T23:39:09+00:00

'this_sector' is a virtual (array) address while 'head_position' is a physical
(device) address, so substraction doesn't make any sense.  devs[slot].addr
should be used instead of this_sector.

However, this patch doesn't make much practical different to the read
balancing due to the effects of later code.

Signed-off-by: Neil Brown 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] md: remove unneeded NULL checks before kfree

2005-06-22T02:07:48+00:00

This patch removes some unneeded checks of pointers being NULL before
calling kfree() on them.  kfree() handles NULL pointers just fine, checking
first is pointless.

Signed-off-by: Jesper Juhl 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds