From patchwork Tue Feb 8 18:03:32 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arne Jansen X-Patchwork-Id: 541221 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter1.kernel.org (8.14.4/8.14.3) with ESMTP id p18I5eYn031347 for ; Tue, 8 Feb 2011 18:05:40 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755170Ab1BHSFh (ORCPT ); Tue, 8 Feb 2011 13:05:37 -0500 Received: from vroomfondel.rzone.de ([81.169.147.145]:49888 "EHLO vroomfondel.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754934Ab1BHSFg (ORCPT ); Tue, 8 Feb 2011 13:05:36 -0500 Received: from sensei.trapni.de (oglaroon.iata [192.168.96.10]) by vroomfondel.rzone.de (Postfix) with ESMTP id 05F374AFC; Tue, 8 Feb 2011 19:05:24 +0100 (MET) Received: by sensei.trapni.de (Postfix, from userid 0) id EA0C69C0A80; Tue, 8 Feb 2011 19:03:32 +0100 (CET) From: Arne Jansen To: chris.mason@oracle.com Cc: josef@redhat.com, miaox@cn.fujitsu.com, linux-btrfs@vger.kernel.org Subject: [PATCH] btrfs: quasi-round-robin for chunk allocation Date: Tue, 8 Feb 2011 19:03:32 +0100 Message-Id: <1297188212-23212-1-git-send-email-sensille@gmx.net> X-Mailer: git-send-email 1.7.2.2 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter1.kernel.org [140.211.167.41]); Tue, 08 Feb 2011 18:05:41 +0000 (UTC) diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index f4e45fd..1664a25 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -864,6 +864,31 @@ static int btrfs_remount(struct super_block *sb, int *flags, char *data) return 0; } +/* Used to sort the devices by max_avail(descending sort) */ +int btrfs_cmp_device_free_bytes(const void *dev_info1, const void *dev_info2) +{ + if (((struct btrfs_device_info *)dev_info1)->max_avail > + ((struct btrfs_device_info *)dev_info2)->max_avail) + return -1; + else if (((struct btrfs_device_info *)dev_info1)->max_avail < + ((struct btrfs_device_info *)dev_info2)->max_avail) + return 1; + else + return 0; +} + +/* + * 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); +} + /* * The helper to calc the free space on the devices that can be used to store * file data. diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index f2d2f4c..a868ca4 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -859,10 +859,7 @@ int find_free_dev_extent(struct btrfs_trans_handle *trans, /* we don't want to overwrite the superblock on the drive, * so we make sure to start at an offset of at least 1MB */ - search_start = 1024 * 1024; - - if (root->fs_info->alloc_start + num_bytes <= search_end) - search_start = max(root->fs_info->alloc_start, search_start); + search_start = max(root->fs_info->alloc_start, 1024ull * 1024); max_hole_start = search_start; max_hole_size = 0; @@ -2255,418 +2252,262 @@ static int btrfs_add_system_chunk(struct btrfs_trans_handle *trans, return 0; } -static noinline u64 chunk_bytes_by_type(u64 type, u64 calc_size, - int num_stripes, int sub_stripes) +/* + * sort the devices in descending order by max_avail, total_avail + */ +static int btrfs_cmp_device_info(const void *a, const void *b) { - if (type & (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_DUP)) - return calc_size; - else if (type & BTRFS_BLOCK_GROUP_RAID10) - return calc_size * (num_stripes / sub_stripes); - else - return calc_size * num_stripes; -} + const struct btrfs_device_info *di_a = a; + const struct btrfs_device_info *di_b = b; -/* Used to sort the devices by max_avail(descending sort) */ -int btrfs_cmp_device_free_bytes(const void *dev_info1, const void *dev_info2) -{ - if (((struct btrfs_device_info *)dev_info1)->max_avail > - ((struct btrfs_device_info *)dev_info2)->max_avail) + if (di_a->max_avail > di_b->max_avail) return -1; - else if (((struct btrfs_device_info *)dev_info1)->max_avail < - ((struct btrfs_device_info *)dev_info2)->max_avail) + if (di_a->max_avail < di_b->max_avail) return 1; - else - return 0; + if (di_a->total_avail > di_b->total_avail) + return -1; + if (di_a->total_avail < di_b->total_avail) + return 1; + return 0; } -static int __btrfs_calc_nstripes(struct btrfs_fs_devices *fs_devices, u64 type, - int *num_stripes, int *min_stripes, - int *sub_stripes) +static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans, + struct btrfs_root *extent_root, + struct map_lookup **map_ret, + u64 *num_bytes, u64 *stripe_size_out, + u64 start, u64 type) { - *num_stripes = 1; - *min_stripes = 1; - *sub_stripes = 0; + struct btrfs_fs_info *info = extent_root->fs_info; + struct btrfs_device *device = NULL; + struct btrfs_fs_devices *fs_devices = info->fs_devices; + struct list_head *cur; + struct map_lookup *map = NULL; + struct extent_map_tree *em_tree; + struct extent_map *em; + struct btrfs_device_info *devices_info = NULL; + u64 total_avail; + u64 max_avail; + u64 dev_offset; + int num_stripes; + int sub_stripes; + int dev_stripes; /* stripes per dev */ + int devs_max; + int devs_min; + int devs_increment; + int ncopies; + int ret; + u64 max_stripe_size; + u64 max_chunk_size; + u64 stripe_size; + int ndevs; + int index; + int i; + int j; - if (type & (BTRFS_BLOCK_GROUP_RAID0)) { - *num_stripes = fs_devices->rw_devices; - *min_stripes = 2; - } - if (type & (BTRFS_BLOCK_GROUP_DUP)) { - *num_stripes = 2; - *min_stripes = 2; - } - if (type & (BTRFS_BLOCK_GROUP_RAID1)) { - if (fs_devices->rw_devices < 2) - return -ENOSPC; - *num_stripes = 2; - *min_stripes = 2; - } - if (type & (BTRFS_BLOCK_GROUP_RAID10)) { - *num_stripes = fs_devices->rw_devices; - if (*num_stripes < 4) - return -ENOSPC; - *num_stripes &= ~(u32)1; - *sub_stripes = 2; - *min_stripes = 4; + if ((type & BTRFS_BLOCK_GROUP_RAID1) && + (type & BTRFS_BLOCK_GROUP_DUP)) { + WARN_ON(1); + type &= ~BTRFS_BLOCK_GROUP_DUP; } - return 0; -} + if (list_empty(&fs_devices->alloc_list)) + return -ENOSPC; -static u64 __btrfs_calc_stripe_size(struct btrfs_fs_devices *fs_devices, - u64 proposed_size, u64 type, - int num_stripes, int small_stripe) -{ - int min_stripe_size = 1 * 1024 * 1024; - u64 calc_size = proposed_size; - u64 max_chunk_size = calc_size; - int ncopies = 1; - if (type & (BTRFS_BLOCK_GROUP_RAID1 | - BTRFS_BLOCK_GROUP_DUP | - BTRFS_BLOCK_GROUP_RAID10)) + sub_stripes = 1; + dev_stripes = 1; + devs_increment = 1; + ncopies = 1; + devs_max = 0; /* 0 == as many as possible */ + devs_min = 1; + + if (type & (BTRFS_BLOCK_GROUP_DUP)) { + dev_stripes = 2; + ncopies = 2; + devs_max = 1; + } else if (type & (BTRFS_BLOCK_GROUP_RAID0)) { + devs_min = 2; + } else if (type & (BTRFS_BLOCK_GROUP_RAID1)) { + devs_increment = 2; ncopies = 2; + devs_max = 2; + devs_min = 2; + } else if (type & (BTRFS_BLOCK_GROUP_RAID10)) { + sub_stripes = 2; + devs_increment = 2; + ncopies = 2; + devs_min = 4; + } if (type & BTRFS_BLOCK_GROUP_DATA) { - max_chunk_size = 10 * calc_size; - min_stripe_size = 64 * 1024 * 1024; + max_stripe_size = 1024 * 1024 * 1024; + max_chunk_size = 10 * max_stripe_size; } else if (type & BTRFS_BLOCK_GROUP_METADATA) { - max_chunk_size = 256 * 1024 * 1024; - min_stripe_size = 32 * 1024 * 1024; + max_stripe_size = 256 * 1024 * 1024; + max_chunk_size = max_stripe_size; } else if (type & BTRFS_BLOCK_GROUP_SYSTEM) { - calc_size = 8 * 1024 * 1024; - max_chunk_size = calc_size * 2; - min_stripe_size = 1 * 1024 * 1024; + max_stripe_size = 8 * 1024 * 1024; + max_chunk_size = 2 * max_stripe_size; + } else { + BUG_ON(1); } /* we don't want a chunk larger than 10% of writeable space */ max_chunk_size = min(div_factor(fs_devices->total_rw_bytes, 1), - max_chunk_size); + max_chunk_size); - if (calc_size * num_stripes > max_chunk_size * ncopies) { - calc_size = max_chunk_size * ncopies; - do_div(calc_size, num_stripes); - do_div(calc_size, BTRFS_STRIPE_LEN); - calc_size *= BTRFS_STRIPE_LEN; - } + devices_info = kzalloc(sizeof(*devices_info) * fs_devices->rw_devices, + GFP_NOFS); + if (!devices_info) + return -ENOMEM; - /* we don't want tiny stripes */ - if (!small_stripe) - calc_size = max_t(u64, min_stripe_size, calc_size); + cur = fs_devices->alloc_list.next; /* - * we're about to do_div by the BTRFS_STRIPE_LEN so lets make sure - * we end up with something bigger than a stripe + * in the first pass through the devices list, we gather information + * about the available holes on each device. */ - calc_size = max_t(u64, calc_size, BTRFS_STRIPE_LEN); - - do_div(calc_size, BTRFS_STRIPE_LEN); - calc_size *= BTRFS_STRIPE_LEN; - - return calc_size; -} - -static struct map_lookup *__shrink_map_lookup_stripes(struct map_lookup *map, - int num_stripes) -{ - struct map_lookup *new; - size_t len = map_lookup_size(num_stripes); - - BUG_ON(map->num_stripes < num_stripes); - - if (map->num_stripes == num_stripes) - return map; - - new = kmalloc(len, GFP_NOFS); - if (!new) { - /* just change map->num_stripes */ - map->num_stripes = num_stripes; - return map; - } - - memcpy(new, map, len); - new->num_stripes = num_stripes; - kfree(map); - return new; -} - -/* - * helper to allocate device space from btrfs_device_info, in which we stored - * max free space information of every device. It is used when we can not - * allocate chunks by default size. - * - * By this helper, we can allocate a new chunk as larger as possible. - */ -static int __btrfs_alloc_tiny_space(struct btrfs_trans_handle *trans, - struct btrfs_fs_devices *fs_devices, - struct btrfs_device_info *devices, - int nr_device, u64 type, - struct map_lookup **map_lookup, - int min_stripes, u64 *stripe_size) -{ - int i, index, sort_again = 0; - int min_devices = min_stripes; - u64 max_avail, min_free; - struct map_lookup *map = *map_lookup; - int ret; - - if (nr_device < min_stripes) - return -ENOSPC; + ndevs = 0; + while (cur != &fs_devices->alloc_list) { + device = list_entry(cur, struct btrfs_device, dev_alloc_list); + BUG_ON(!device->writeable); - btrfs_descending_sort_devices(devices, nr_device); + cur = cur->next; - max_avail = devices[0].max_avail; - if (!max_avail) - return -ENOSPC; + if (!device->in_fs_metadata) + continue; - for (i = 0; i < nr_device; i++) { - /* - * if dev_offset = 0, it means the free space of this device - * is less than what we need, and we didn't search max avail - * extent on this device, so do it now. + if (device->total_bytes > device->bytes_used) + total_avail = device->total_bytes - device->bytes_used; + else + total_avail = 0; + /* avail is off by max(alloc_start, 1MB), but that is the same + * for all devices, so it doesn't hurt the sorting later on */ - if (!devices[i].dev_offset) { - ret = find_free_dev_extent(trans, devices[i].dev, - max_avail, - &devices[i].dev_offset, - &devices[i].max_avail); - if (ret != 0 && ret != -ENOSPC) - return ret; - sort_again = 1; - } - } - - /* we update the max avail free extent of each devices, sort again */ - if (sort_again) - btrfs_descending_sort_devices(devices, nr_device); - if (type & BTRFS_BLOCK_GROUP_DUP) - min_devices = 1; + ret = find_free_dev_extent(trans, device, + max_stripe_size * dev_stripes, + &dev_offset, &max_avail); + if (ret && ret != -ENOSPC) + goto error; - if (!devices[min_devices - 1].max_avail) - return -ENOSPC; + if (ret == 0) + max_avail = max_stripe_size * dev_stripes; - max_avail = devices[min_devices - 1].max_avail; - if (type & BTRFS_BLOCK_GROUP_DUP) - do_div(max_avail, 2); + if (max_avail < BTRFS_STRIPE_LEN * dev_stripes) + continue; - max_avail = __btrfs_calc_stripe_size(fs_devices, max_avail, type, - min_stripes, 1); - if (type & BTRFS_BLOCK_GROUP_DUP) - min_free = max_avail * 2; - else - min_free = max_avail; + devices_info[ndevs].dev_offset = dev_offset; + devices_info[ndevs].max_avail = max_avail; + devices_info[ndevs].total_avail = total_avail; + devices_info[ndevs].dev = device; + ++ndevs; + } - if (min_free > devices[min_devices - 1].max_avail) - return -ENOSPC; + /* + * now sort the devices by hole size / available space + */ + sort(devices_info, ndevs, sizeof(struct btrfs_device_info), + btrfs_cmp_device_info, NULL); - map = __shrink_map_lookup_stripes(map, min_stripes); - *stripe_size = max_avail; + /* round down to number of usable stripes */ + ndevs -= ndevs % devs_increment; - index = 0; - for (i = 0; i < min_stripes; i++) { - map->stripes[i].dev = devices[index].dev; - map->stripes[i].physical = devices[index].dev_offset; - if (type & BTRFS_BLOCK_GROUP_DUP) { - i++; - map->stripes[i].dev = devices[index].dev; - map->stripes[i].physical = devices[index].dev_offset + - max_avail; - } - index++; + if (ndevs < devs_increment * sub_stripes || ndevs < devs_min) { + ret = -ENOSPC; + goto error; } - *map_lookup = map; - return 0; -} - -static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans, - struct btrfs_root *extent_root, - struct map_lookup **map_ret, - u64 *num_bytes, u64 *stripe_size, - u64 start, u64 type) -{ - struct btrfs_fs_info *info = extent_root->fs_info; - struct btrfs_device *device = NULL; - struct btrfs_fs_devices *fs_devices = info->fs_devices; - struct list_head *cur; - struct map_lookup *map; - struct extent_map_tree *em_tree; - struct extent_map *em; - struct btrfs_device_info *devices_info; - struct list_head private_devs; - u64 calc_size = 1024 * 1024 * 1024; - u64 min_free; - u64 avail; - u64 dev_offset; - int num_stripes; - int min_stripes; - int sub_stripes; - int min_devices; /* the min number of devices we need */ - int i; - int ret; - int index; + if (devs_max && ndevs > devs_max) + ndevs = devs_max; + /* + * the primary goal is to maximize the number of stripes, so use as many + * devices as possible, even if the stripes are not maximum sized. + */ + stripe_size = devices_info[ndevs-1].max_avail; + num_stripes = ndevs * dev_stripes; - if ((type & BTRFS_BLOCK_GROUP_RAID1) && - (type & BTRFS_BLOCK_GROUP_DUP)) { - WARN_ON(1); - type &= ~BTRFS_BLOCK_GROUP_DUP; + if (stripe_size * num_stripes > max_chunk_size * ncopies) { + stripe_size = max_chunk_size * ncopies; + do_div(stripe_size, num_stripes); } - if (list_empty(&fs_devices->alloc_list)) - return -ENOSPC; - ret = __btrfs_calc_nstripes(fs_devices, type, &num_stripes, - &min_stripes, &sub_stripes); - if (ret) - return ret; + do_div(stripe_size, dev_stripes); + do_div(stripe_size, BTRFS_STRIPE_LEN); + stripe_size *= BTRFS_STRIPE_LEN; - devices_info = kzalloc(sizeof(*devices_info) * fs_devices->rw_devices, - GFP_NOFS); - if (!devices_info) - return -ENOMEM; + BUG_ON(!stripe_size); map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS); if (!map) { ret = -ENOMEM; goto error; } map->num_stripes = num_stripes; - cur = fs_devices->alloc_list.next; index = 0; - i = 0; - - calc_size = __btrfs_calc_stripe_size(fs_devices, calc_size, type, - num_stripes, 0); - - if (type & BTRFS_BLOCK_GROUP_DUP) { - min_free = calc_size * 2; - min_devices = 1; - } else { - min_free = calc_size; - min_devices = min_stripes; - } - - INIT_LIST_HEAD(&private_devs); - while (index < num_stripes) { - device = list_entry(cur, struct btrfs_device, dev_alloc_list); - BUG_ON(!device->writeable); - if (device->total_bytes > device->bytes_used) - avail = device->total_bytes - device->bytes_used; - else - avail = 0; - cur = cur->next; - - if (device->in_fs_metadata && avail >= min_free) { - ret = find_free_dev_extent(trans, device, min_free, - &devices_info[i].dev_offset, - &devices_info[i].max_avail); - if (ret == 0) { - list_move_tail(&device->dev_alloc_list, - &private_devs); - map->stripes[index].dev = device; - map->stripes[index].physical = - devices_info[i].dev_offset; - index++; - if (type & BTRFS_BLOCK_GROUP_DUP) { - map->stripes[index].dev = device; - map->stripes[index].physical = - devices_info[i].dev_offset + - calc_size; - index++; - } - } else if (ret != -ENOSPC) - goto error; - - devices_info[i].dev = device; - i++; - } else if (device->in_fs_metadata && - avail >= BTRFS_STRIPE_LEN) { - devices_info[i].dev = device; - devices_info[i].max_avail = avail; - i++; - } - - if (cur == &fs_devices->alloc_list) - break; - } - - list_splice(&private_devs, &fs_devices->alloc_list); - if (index < num_stripes) { - if (index >= min_stripes) { - num_stripes = index; - if (type & (BTRFS_BLOCK_GROUP_RAID10)) { - num_stripes /= sub_stripes; - num_stripes *= sub_stripes; - } - - map = __shrink_map_lookup_stripes(map, num_stripes); - } else if (i >= min_devices) { - ret = __btrfs_alloc_tiny_space(trans, fs_devices, - devices_info, i, type, - &map, min_stripes, - &calc_size); - if (ret) - goto error; - } else { - ret = -ENOSPC; - goto error; + for (i = 0; i < ndevs; ++i) { + for (j = 0; j < dev_stripes; ++j) { + int s = i * dev_stripes + j; + map->stripes[s].dev = devices_info[i].dev; + map->stripes[s].physical = devices_info[i].dev_offset + + j * stripe_size; } } map->sector_size = extent_root->sectorsize; map->stripe_len = BTRFS_STRIPE_LEN; map->io_align = BTRFS_STRIPE_LEN; map->io_width = BTRFS_STRIPE_LEN; map->type = type; map->sub_stripes = sub_stripes; *map_ret = map; - *stripe_size = calc_size; - *num_bytes = chunk_bytes_by_type(type, calc_size, - map->num_stripes, sub_stripes); + *stripe_size_out = stripe_size; + *num_bytes = stripe_size * (num_stripes / ncopies); em = alloc_extent_map(GFP_NOFS); if (!em) { ret = -ENOMEM; goto error; } em->bdev = (struct block_device *)map; em->start = start; em->len = *num_bytes; em->block_start = 0; em->block_len = em->len; em_tree = &extent_root->fs_info->mapping_tree.map_tree; write_lock(&em_tree->lock); ret = add_extent_mapping(em_tree, em); write_unlock(&em_tree->lock); BUG_ON(ret); free_extent_map(em); ret = btrfs_make_block_group(trans, extent_root, 0, type, BTRFS_FIRST_CHUNK_TREE_OBJECTID, start, *num_bytes); BUG_ON(ret); index = 0; while (index < map->num_stripes) { device = map->stripes[index].dev; dev_offset = map->stripes[index].physical; ret = btrfs_alloc_dev_extent(trans, device, info->chunk_root->root_key.objectid, BTRFS_FIRST_CHUNK_TREE_OBJECTID, - start, dev_offset, calc_size); + start, dev_offset, stripe_size); BUG_ON(ret); index++; } kfree(devices_info); return 0; error: - kfree(map); kfree(devices_info); + kfree(map); + return ret; } diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h index 7af6144..f4fe792 100644 --- a/fs/btrfs/volumes.h +++ b/fs/btrfs/volumes.h @@ -144,23 +144,9 @@ struct btrfs_device_info { struct btrfs_device *dev; u64 dev_offset; u64 max_avail; + u64 total_avail; }; -/* 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);