Commits · 18af8b2ca34b831c32c6fa01e7ce33143c33bb63 · Kirill Smelkov / linux

29 Dec, 2008 37 commits

block: use min_not_zero in blk_queue_stack_limits · 18af8b2c

FUJITA Tomonori authored Dec 04, 2008

zero is invalid for max_phys_segments, max_hw_segments, and
max_segment_size. It's better to use use min_not_zero instead of
min. min() works though (because the commit 0e435ac2 makes sure that
these values are set to the default values, non zero, if a queue is
initialized properly).

With this patch, blk_queue_stack_limits does the almost same thing
that dm's combine_restrictions_low() does. I think that it's easy to
remove dm's combine_restrictions_low.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

18af8b2c

block: add one-hit cache for disk partition lookup · a6f23657

Jens Axboe authored Oct 24, 2008

disk_map_sector_rcu() returns a partition from a sector offset,
which we use for IO statistics on a per-partition basis. The
lookup itself is an O(N) list lookup, where N is the number of
partitions. This actually hurts performance quite a bit, even
on the lower end partitions. On higher numbered partitions,
it can get pretty bad.

Solve this by adding a one-hit cache for partition lookup.
This makes the lookup O(1) for the case where we do most IO to
one partition. Even for mixed partition workloads, amortized cost
is pretty close to O(1) since the natural IO batching makes the
one-hit cache last for lots of IOs.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

a6f23657

cfq-iosched: remove limit of dispatch depth of max 4 times quantum · 30e0dc28

Jens Axboe authored Oct 20, 2008

This basically limits the hardware queue depth to 4*quantum at any
point in time, which is 16 with the default settings. As CFQ uses
other means to shrink the hardware queue when necessary in the first
place, there's really no need for this extra heuristic. Additionally,
it ends up hurting performance in some cases.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

30e0dc28

nbd: tell the block layer that it is not a rotational device · 31dcfab0

Jens Axboe authored Oct 31, 2008

Then we can get rid of that manual elevator type fiddling.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

31dcfab0

block: get rid of elevator_t typedef · b374d18a

Jens Axboe authored Oct 31, 2008

Just use struct elevator_queue everywhere instead.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

b374d18a

aio: make the lookup_ioctx() lockless · abf137dd

Jens Axboe authored Dec 09, 2008

The mm->ioctx_list is currently protected by a reader-writer lock,
so we always grab that lock on the read side for doing ioctx
lookups. As the workload is extremely reader biased, turn this into
an rcu hlist so we can make lookup_ioctx() lockless. Get rid of
the rwlock and use a spinlock for providing update side exclusion.

There's usually only 1 entry on this list, so it doesn't make sense
to look into fancier data structures.
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

abf137dd

bio: add support for inlining a number of bio_vecs inside the bio · 392ddc32

Jens Axboe authored Dec 23, 2008

When we go and allocate a bio for IO, we actually do two allocations.
One for the bio itself, and one for the bi_io_vec that holds the
actual pages we are interested in.

This feature inlines a definable amount of io vecs inside the bio
itself, so we eliminate the bio_vec array allocation for IO's up
to a certain size. It defaults to 4 vecs, which is typically 16k
of IO.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

392ddc32

bio: allow individual slabs in the bio_set · bb799ca0

Jens Axboe authored Dec 10, 2008

Instead of having a global bio slab cache, add a reference to one
in each bio_set that is created. This allows for personalized slabs
in each bio_set, so that they can have bios of different sizes.

This means we can personalize the bios we return. File systems may
want to embed the bio inside another structure, to avoid allocation
more items (and stuffing them in ->bi_private) after the get a bio.
Or we may want to embed a number of bio_vecs directly at the end
of a bio, to avoid doing two allocations to return a bio. This is now
possible.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

bb799ca0

bio: move the slab pointer inside the bio_set · 1b434498

Jens Axboe authored Oct 22, 2008

In preparation for adding differently sized bios.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1b434498

bio: only mempool back the largest bio_vec slab cache · 7ff9345f

Jens Axboe authored Dec 11, 2008

We only very rarely need the mempool backing, so it makes sense to
get rid of all but one of the mempool in a bio_set. So keep the
largest bio_vec count mempool so we can always honor the largest
allocation, and "upgrade" callers that fail.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

7ff9345f

block: don't use plugging on SSD devices · a31a9738

Jens Axboe authored Oct 17, 2008

We just want to hand the first bits of IO to the device as fast
as possible. Gains a few percent on the IOPS rate.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

a31a9738