xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

md: add proper merge_bvec handling to RAID0 and Linear.

Browse Source 
These personalities currently set a max request size of one page
when any member device has a merge_bvec_fn because they don't
bother to call that function.

This causes extra works in splitting and combining requests.

So make the extra effort to call the merge_bvec_fn when it exists
so that we end up with larger requests out the bottom.

Signed-off-by: NeilBrown <neilb@suse.de>
This commit is contained in:
NeilBrown
2012-03-19 12:46:39 +11:00
parent dafb20fa34
commit ba13da47ff
3 changed files with 107 additions and 88 deletions
Download Patch File Download Diff File Expand all files Collapse all files

30
drivers/md/linear.c
View File

@@ -68,10 +68,19 @@ static int linear_mergeable_bvec(struct request_queue *q,
struct dev_info *dev0;
unsigned long maxsectors, bio_sectors = bvm->bi_size >> 9;
sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
int maxbytes = biovec->bv_len;
struct request_queue *subq;
rcu_read_lock();
dev0 = which_dev(mddev, sector);
maxsectors = dev0->end_sector - sector;
subq = bdev_get_queue(dev0->rdev->bdev);
if (subq->merge_bvec_fn) {
bvm->bi_bdev = dev0->rdev->bdev;
bvm->bi_sector -= dev0->end_sector - dev0->rdev->sectors;
maxbytes = min(maxbytes, subq->merge_bvec_fn(subq, bvm,
biovec));
}
rcu_read_unlock();
if (maxsectors < bio_sectors)
@@ -80,12 +89,12 @@ static int linear_mergeable_bvec(struct request_queue *q,
maxsectors -= bio_sectors;
if (maxsectors <= (PAGE_SIZE >> 9 ) && bio_sectors == 0)
return biovec->bv_len;
/* The bytes available at this offset could be really big,
* so we cap at 2^31 to avoid overflow */
if (maxsectors > (1 << (31-9)))
return 1<<31;
return maxsectors << 9;
return maxbytes;
if (maxsectors > (maxbytes >> 9))
return maxbytes;
else
return maxsectors << 9;
}
static int linear_congested(void *data, int bits)
@@ -158,15 +167,6 @@ static struct linear_conf *linear_conf(struct mddev *mddev, int raid_disks)
disk_stack_limits(mddev->gendisk, rdev->bdev,
rdev->data_offset << 9);
/* as we don't honour merge_bvec_fn, we must never risk
* violating it, so limit max_segments to 1 lying within
* a single page.
*/
if (rdev->bdev->bd_disk->queue->merge_bvec_fn) {
blk_queue_max_segments(mddev->queue, 1);
blk_queue_segment_boundary(mddev->queue,
PAGE_CACHE_SIZE - 1);
}
conf->array_sectors += rdev->sectors;
cnt++;