btrfs: preallocate radix tree node for readahead

We can preallocate the node so insertion does not have to do that under
the lock. The GFP flags for the per-device radix tree are initialized to
 GFP_NOFS & ~__GFP_DIRECT_RECLAIM
but we can use GFP_KERNEL, same as an allocation above anyway, but also
because readahead is optional and not on any critical writeout path.

Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
David Sterba 2017-03-02 18:54:52 +01:00
parent 261cc2cca0
commit cc8385b59e
2 changed files with 8 additions and 1 deletions

View File

@ -270,6 +270,12 @@ static struct reada_zone *reada_find_zone(struct btrfs_fs_info *fs_info,
if (!zone)
return NULL;
ret = radix_tree_preload(GFP_KERNEL);
if (ret) {
kfree(zone);
return NULL;
}
zone->start = start;
zone->end = end;
INIT_LIST_HEAD(&zone->list);
@ -299,6 +305,7 @@ static struct reada_zone *reada_find_zone(struct btrfs_fs_info *fs_info,
zone = NULL;
}
spin_unlock(&fs_info->reada_lock);
radix_tree_preload_end();
return zone;
}

View File

@ -252,7 +252,7 @@ static struct btrfs_device *__alloc_device(void)
atomic_set(&dev->reada_in_flight, 0);
atomic_set(&dev->dev_stats_ccnt, 0);
btrfs_device_data_ordered_init(dev);
INIT_RADIX_TREE(&dev->reada_zones, GFP_NOFS & ~__GFP_DIRECT_RECLAIM);
INIT_RADIX_TREE(&dev->reada_zones, GFP_KERNEL);
INIT_RADIX_TREE(&dev->reada_extents, GFP_NOFS & ~__GFP_DIRECT_RECLAIM);
return dev;