From bcd53741cc2af4342ac3ff6983bddc4a1b63b9b4 Mon Sep 17 00:00:00 2001 From: Arne Jansen Date: Tue, 12 Apr 2011 10:43:21 +0200 Subject: btrfs: move btrfs_cmp_device_free_bytes to super.c this function won't be used here anymore, so move it super.c where it is used for df-calculation --- fs/btrfs/volumes.h | 15 --------------- 1 file changed, 15 deletions(-) (limited to 'fs/btrfs/volumes.h') diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h index cc2eada..b502f01 100644 --- a/fs/btrfs/volumes.h +++ b/fs/btrfs/volumes.h @@ -157,21 +157,6 @@ struct map_lookup { struct btrfs_bio_stripe stripes[]; }; -/* Used to sort the devices by max_avail(descending sort) */ -int btrfs_cmp_device_free_bytes(const void *dev_info1, const void *dev_info2); - -/* - * sort the devices by max_avail, in which max free extent size of each device - * is stored.(Descending Sort) - */ -static inline void btrfs_descending_sort_devices( - struct btrfs_device_info *devices, - size_t nr_devices) -{ - sort(devices, nr_devices, sizeof(struct btrfs_device_info), - btrfs_cmp_device_free_bytes, NULL); -} - int btrfs_account_dev_extents_size(struct btrfs_device *device, u64 start, u64 end, u64 *length); -- cgit v1.1 From 73c5de0051533cbdf2bb656586c3eb21a475aa7d Mon Sep 17 00:00:00 2001 From: Arne Jansen Date: Tue, 12 Apr 2011 12:07:57 +0200 Subject: btrfs: quasi-round-robin for chunk allocation In a multi device setup, the chunk allocator currently always allocates chunks on the devices in the same order. This leads to a very uneven distribution, especially with RAID1 or RAID10 and an uneven number of devices. This patch always sorts the devices before allocating, and allocates the stripes on the devices with the most available space, as long as there is enough space available. In a low space situation, it first tries to maximize striping. The patch also simplifies the allocator and reduces the checks for corner cases. The simplification is done by several means. First, it defines the properties of each RAID type upfront. These properties are used afterwards instead of differentiating cases in several places. Second, the old allocator defined a minimum stripe size for each block group type, tried to find a large enough chunk, and if this fails just allocates a smaller one. This is now done in one step. The largest possible chunk (up to max_chunk_size) is searched and allocated. Because we now have only one pass, the allocation of the map (struct map_lookup) is moved down to the point where the number of stripes is already known. This way we avoid reallocation of the map. We still avoid allocating stripes that are not a multiple of STRIPE_SIZE. --- fs/btrfs/volumes.h | 1 + 1 file changed, 1 insertion(+) (limited to 'fs/btrfs/volumes.h') diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h index b502f01..37ae6e2 100644 --- a/fs/btrfs/volumes.h +++ b/fs/btrfs/volumes.h @@ -144,6 +144,7 @@ struct btrfs_device_info { struct btrfs_device *dev; u64 dev_offset; u64 max_avail; + u64 total_avail; }; struct map_lookup { -- cgit v1.1