- 07 Jan, 2022 40 commits
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Qu Wenruo authored
Currently there is only one user for btrfs metadata readahead, and that's scrub. But even for the single user, it's not providing the correct functionality it needs, as scrub needs reada for commit root, which current readahead can't provide. (Although it's pretty easy to add such feature). Despite this, there are some extra problems related to metadata readahead: - Duplicated feature with btrfs_path::reada - Partly duplicated feature of btrfs_fs_info::buffer_radix Btrfs already caches its metadata in buffer_radix, while readahead tries to read the tree block no matter if it's already cached. - Poor layer separation Metadata readahead works kinda at device level. This is definitely not the correct layer it should be, since metadata is at btrfs logical address space, it should not bother device at all. This brings extra chance for bugs to sneak in, while brings unnecessary complexity. - Dead code In the very beginning of scrub.c we have #undef DEBUG, rendering all the debug related code useless and unable to test. Thus here I purpose to remove the metadata readahead mechanism completely. [BENCHMARK] There is a full benchmark for the scrub performance difference using the old btrfs_reada_add() and btrfs_path::reada. For the worst case (no dirty metadata, slow HDD), there could be a 5% performance drop for scrub. For other cases (even SATA SSD), there is no distinguishable performance difference. The number is reported scrub speed, in MiB/s. The resolution is limited by the reported duration, which only has a resolution of 1 second. Old New Diff SSD 455.3 466.332 +2.42% HDD 103.927 98.012 -5.69% Comprehensive test methodology is in the cover letter of the patch. Signed-off-by:
Qu Wenruo <wqu@suse.com> Signed-off-by:
David Sterba <dsterba@suse.com>
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Qu Wenruo authored
For scrub, we trigger two readaheads for two trees, extent tree to get where to scrub, and csum tree to get the data checksum. For csum tree we already trigger readahead in btrfs_lookup_csums_range(), by setting path->reada. But for extent tree we don't have any path based readahead. Add the readahead for extent tree as well, so we can later remove the btrfs_reada_add() based readahead. Signed-off-by:
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Qu Wenruo authored
In function scrub_stripe() we allocated two btrfs_path's, one @path for extent tree search and another @ppath for full stripe extent tree search for RAID56. This is totally umncessary, as the @ppath usage is completely inside scrub_raid56_parity(), thus we can move the path allocation into scrub_raid56_parity() completely. Signed-off-by:
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Nikolay Borisov authored
The purpose of this function is to unlock all nodes in a btrfs path which are above 'lowest_unlock' and whose slot used is different than 0. As such it used slightly awkward structure of 'if' as well as somewhat cryptic "no_skip" control variable which denotes whether we should check the current level of skipability or no. This patch does the following (cosmetic) refactorings: * Renames 'no_skip' to 'check_skip' and makes it a boolean. This variable controls whether we are below the lowest_unlock/skip_level levels. * Consolidates the 2 conditions which warrant checking whether the current level should be skipped under 1 common if (check_skip) branch, this increase indentation level but is not critical. * Consolidates the 'skip_level < i && i >= lowest_unlock' and 'i >= lowest_unlock && i > skip_level' condition into a common branch since those are identical. * Eliminates the local extent_buffer variable as in this case it doesn't bring anything to function readability. Reviewed-by:
Josef Bacik <josef@toxicpanda.com> Signed-off-by:
Nikolay Borisov <nborisov@suse.com> Reviewed-by:
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Filipe Manana authored
At ioctl.c:create_subvol(), when we fail to create a subvolume we always commit the transaction. In most cases this is a no-op, since all the error paths, except for one, abort the transaction - the only exception is when we fail to insert the new root item into the root tree, in that case we don't abort the transaction because we didn't do anything that is irreversible - however we end up committing the transaction which although is not a functional problem, it adds unnecessary rotation of the backup roots in the superblock and unnecessary work. So change that to commit a transaction only when no error happened, otherwise just call btrfs_end_transaction() to release our reference on the transaction. Reviewed-by:
Filipe Manana <fdmanana@suse.com> Signed-off-by:
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Naohiro Aota authored
The ZNS specification defines a limit on the number of "active" zones. That limit impose us to limit the number of block groups which can be used for an allocation at the same time. Not to exceed the limit, we reuse the existing active block groups as much as possible when we can't activate any other zones without sacrificing an already activated block group in commit a85f05e5 ("btrfs: zoned: avoid chunk allocation if active block group has enough space"). However, the check is wrong in two ways. First, it checks the condition for every raid index (ffe_ctl->index). Even if it reaches the condition and "ffe_ctl->max_extent_size >= ffe_ctl->min_alloc_size" is met, there can be other block groups having enough space to hold ffe_ctl->num_bytes. (Actually, this won't happen in the current zoned code as it only supports SINGLE profile. But, it can happen once it enables other RAID types.) Second, it checks the active zone availability depending on the raid index. The raid index is just an index for space_info->block_groups, so it has nothing to do with chunk allocation. These mistakes are causing a faulty allocation in a certain situation. Consider we are running zoned btrfs on a device whose max_active_zone == 0 (no limit). And, suppose no block group have a room to fit ffe_ctl->num_bytes but some room to meet ffe_ctl->min_alloc_size (i.e. max_extent_size > num_bytes >= min_alloc_size). In this situation, the following occur: - With SINGLE raid_index, it reaches the chunk allocation checking code - The check returns true because we can activate a new zone (no limit) - But, before allocating the chunk, it iterates to the next raid index (RAID5) - Since there are no RAID5 block groups on zoned mode, it again reaches the check code - The check returns false because of btrfs_can_activate_zone()'s "if (raid_index != BTRFS_RAID_SINGLE)" part - That results in returning -ENOSPC without allocating a new chunk As a result, we end up hitting -ENOSPC too early. Move the check to the right place in the can_allocate_chunk() hook, and do the active zone check depending on the allocation flag, not on the raid index. CC: stable@vger.kernel.org # 5.16 Signed-off-by:
Naohiro Aota <naohiro.aota@wdc.com> Signed-off-by:
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Naohiro Aota authored
Introduce a new hook for an extent allocator policy. With the new hook, a policy can decide to allocate a new block group or not. If not, it will return -ENOSPC, so btrfs_reserve_extent() will cut the allocation size in half and retry the allocation if min_alloc_size is large enough. The hook has a place holder and will be replaced with the real implementation in the next patch. CC: stable@vger.kernel.org # 5.16 Signed-off-by:
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Naohiro Aota authored
Allocating an extent from a block group can fail for various reasons. When an allocation from a dedicated block group (for tree-log or relocation data) fails, we need to unregister it as a dedicated one so that we can allocate a new block group for the dedicated one. However, we are returning early when the block group in case it is read-only, fully used, or not be able to activate the zone. As a result, we keep the non-usable block group as a dedicated one, leading to further allocation failure. With many block groups, the allocator will iterate hopeless loop to find a free extent, results in a hung task. Fix the issue by delaying the return and doing the proper cleanups. CC: stable@vger.kernel.org # 5.16 Signed-off-by:
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Johannes Thumshirn authored
REQ_OP_ZONE_APPEND can only work on zoned devices, so it is redundant to check if the filesystem is zoned when REQ_OP_ZONE_APPEND is set as the bio's bio_op. Reviewed-by:
Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by:
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Johannes Thumshirn authored
Sink zone check into btrfs_repair_one_zone() so we don't need to do it in all callers. Also as btrfs_repair_one_zone() doesn't return a sensible error, make it a boolean function and return false in case it got called on a non-zoned filesystem and true on a zoned filesystem. Reviewed-by:
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Johannes Thumshirn authored
btrfs_check_meta_write_pointer() will always be called with a NULL 'cache_ret' argument. As there's no need to check if we have a valid block_group passed in remove these checks. Reviewed-by:
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Johannes Thumshirn authored
Encapsulate the inode lock needed for serializing the data relocation writes on a zoned filesystem into a helper. This streamlines the code reading flow and hides special casing for zoned filesystems. Reviewed-by:
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Anand Jain authored
In the case of the seed device, the fsid can be different from the mounted sprout fsid. The userland has to read the device superblock to know the fsid but, that idea fails if the device is missing. So add a sysfs interface devinfo/<devid>/fsid to show the fsid of the device. For example: $ cd /sys/fs/btrfs/b10b02a5-f9de-4276-b9e8-2bfd09a578a8 $ cat devinfo/1/fsid c44d771f-639d-4df3-99ec-5bc7ad2af93b $ cat devinfo/3/fsid b10b02a5-f9de-4276-b9e8-2bfd09a578a8 Though it's related to seeding, the name of the sysfs file is plain fsid as it matches what blkid says. A path to the device's fsid will aid scripting. Reviewed-by:
Anand Jain <anand.jain@oracle.com> Reviewed-by:
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Josef Bacik authored
Filipe reported a problem where sometimes he'd get an ENOSPC abort when running delayed refs with generic/619 and the free space tree enabled. This is partly because we do not reserve space for modifying the free space tree, nor do we have a block rsv associated with that tree. The delayed_refs_rsv tracks the amount of space required to run delayed refs. This means 1 modification means 1 change to the extent root. With the free space tree this turns into 2 changes, because modifying 1 extent means updating the extent tree and potentially updating the free space tree to either remove that entry or add the free space. Thus if we have the FST enabled, simply double the reservation size for our modification. Reviewed-by:
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Josef Bacik authored
Filipe reported a problem where generic/619 was failing with an ENOSPC abort while running delayed refs, like the following BTRFS: Transaction aborted (error -28) WARNING: CPU: 3 PID: 522920 at fs/btrfs/free-space-tree.c:1049 add_to_free_space_tree+0xe5/0x110 [btrfs] CPU: 3 PID: 522920 Comm: kworker/u16:19 Tainted: G W 5.16.0-rc2-btrfs-next-106 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 Workqueue: events_unbound btrfs_async_reclaim_metadata_space [btrfs] RIP: 0010:add_to_free_space_tree+0xe5/0x110 [btrfs] RSP: 0000:ffffa65087fb7b20 EFLAGS: 00010282 RAX: 0000000000000000 RBX: 0000000000001000 RCX: 0000000000000000 RDX: 0000000000000001 RSI: ffffffff9131eeaa RDI: 00000000ffffffff RBP: ffff8d62e26481b8 R08: ffffffff9ad97ce0 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000001 R12: 00000000ffffffe4 R13: ffff8d61c25fe688 R14: ffff8d61ebd88800 R15: ffff8d61ebd88a90 FS: 0000000000000000(0000) GS:ffff8d64ed400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fa46a8b1000 CR3: 0000000148d18003 CR4: 0000000000370ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> __btrfs_free_extent+0x516/0x950 [btrfs] __btrfs_run_delayed_refs+0x2b1/0x1250 [btrfs] btrfs_run_delayed_refs+0x86/0x210 [btrfs] flush_space+0x403/0x630 [btrfs] ? call_rcu_tasks_generic+0x50/0x80 ? lock_release+0x223/0x4a0 ? btrfs_get_alloc_profile+0xb5/0x290 [btrfs] ? do_raw_spin_unlock+0x4b/0xa0 btrfs_async_reclaim_metadata_space+0x139/0x320 [btrfs] process_one_work+0x24c/0x5b0 worker_thread+0x55/0x3c0 ? process_one_work+0x5b0/0x5b0 kthread+0x17c/0x1a0 ? set_kthread_struct+0x40/0x40 ret_from_fork+0x22/0x30 There's a couple of reasons for this, but in generic/619's case the largest reason is because it is a very small file system, ad we do not reserve enough space for the global reserve. With the free space tree we now have the free space tree that we need to modify when running delayed refs. This means we need the global reserve to take this into account when it calculates the minimum size it needs to be. This is especially important for very small file systems. Fix this by adjusting the minimum global block rsv size math to include the size of the free space tree when calculating the size. Reviewed-by:
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Qu Wenruo authored
These two values were introduced in commit ff023aac ("Btrfs: add code to scrub to copy read data to another disk") as an optimization. But the truth is, block layer scheduler can do whatever it wants to merge/split bios to improve performance. Doing such "optimization" is not really going to affect much, especially considering how good current block layer optimizations are doing. Remove such old and immature optimization from our code. Since we're here, also change BUG_ON()s using these two macros to use ASSERT()s. Signed-off-by:
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Qu Wenruo authored
Use BTRFS_MAX_METADATA_BLOCKSIZE and SZ_4K (minimal sectorsize) to calculate this value. And remove one stale comment on the value, in fact with recent subpage support, BTRFS_MAX_METADATA_BLOCKSIZE * PAGE_SIZE is already beyond BTRFS_STRIPE_LEN, just we don't use the full page. Also since we're here, update the BUG_ON() related to SCRUB_MAX_PAGES_PER_BLOCK to ASSERT(). As those ASSERT() are really only for developers to catch early obvious bugs, not to let end users suffer. Signed-off-by:
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Josef Bacik authored
We only throttle the btrfs_truncate_inode_items if the root is SHAREABLE, which isn't set on the log root, which means this loop is unnecessary. Reviewed-by:
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Josef Bacik authored
We reset this bool on every loop through the truncate loop, make this variable local to the loop. Reviewed-by:
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Josef Bacik authored
We have if (del_item) // do something else // something else if (del_item) // do yet another thing else // something else entirely back to back in btrfs_truncate_inode_items, collapse these two sets of if statements into one. Reviewed-by: -
Josef Bacik authored
This is a logic correctness check, convert it into an ASSERT() instead of a BUG(). Reviewed-by:
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Josef Bacik authored
We have a correctness BUG_ON() in btrfs_truncate_inode_items to make sure that we're always using min_type == BTRFS_EXTENT_DATA_KEY if new_size is > 0. Convert this to an ASSERT. Reviewed-by:
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Josef Bacik authored
In the future we're going to want to use btrfs_truncate_inode_items without looking up the associated inode. In order to accommodate this add the inode to btrfs_truncate_control and handle the case where control->inode is NULL appropriately. This is fairly straightforward, we simply need to add a helper for the trace points, as the file extent map update is controlled by a flag on btrfs_truncate_control. Reviewed-by:
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Josef Bacik authored
In the future we are going to want to truncate inode items without needing to have an btrfs_inode to pass in, so add ino to the btrfs_truncate_control and use that to look up the inode items to truncate. Reviewed-by:
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Josef Bacik authored
We only care about updating the file extent range when we are doing a normal truncation. We skip this for tree logging currently, but we can also skip this for eviction as well. Using a flag makes it more explicit when we want to do this work. Reviewed-by:
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Josef Bacik authored
We've had weird bugs in the past where we forgot to adjust the truncate path to deal with the fact that we can be called by the tree log path. Instead of checking if our root is a LOG_ROOT use a flag on the btrfs_truncate_control to indicate that we don't want to do extent reference updates during this truncate. Reviewed-by:
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Josef Bacik authored
We currently have a bunch of awkward checks to make sure we only update the inode i_bytes if we're truncating the real inode. Instead keep track of the number of bytes we need to sub in the btrfs_truncate_control, and then do the appropriate adjustment in the truncate paths that care. Reviewed-by:
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Josef Bacik authored
We currently will update the i_size of the inode as we truncate it down, however we skip this if we're calling btrfs_truncate_inode_items from the tree log code. However we also don't care about this in the case of evict. Instead keep track of this value in the btrfs_truncate_control and then have btrfs_truncate() and the free space cache truncate path both do the i_size update themselves. Reviewed-by:
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Josef Bacik authored
I'm going to be adding more arguments and counters to btrfs_truncate_inode_items, so add a control struct to handle all of the extra arguments to make it easier to follow. Reviewed-by:
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Josef Bacik authored
We only set this if we find a normal file extent, del_item == 1, and the file extent points to a real extent and isn't a hole extent. We can use del_item == 1 && extent_start != 0 to get the same information that found_extent provides, so remove this variable and use the other variables instead. Reviewed-by:
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Josef Bacik authored
We have a special case in btrfs_truncate_inode_items() to call btrfs_kill_delayed_inode_items() if min_type == 0, which is only called during evict. Instead move this out into evict proper, and add some comments because I erroneously attempted to remove this code altogether without understanding what we were doing. Evict is updating the inode only because we only care about making sure the i_nlink count has hit disk. If we had pending deletions we don't want to process those via the delayed inode updates, we simply want to drop all of them and reclaim the reserved metadata space. Then from there the btrfs_truncate_inode_items() will do the work to remove all of the items as appropriate. Reviewed-by:
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Josef Bacik authored
We no longer have inode cache feature, so this check is extraneous as the only inode cache is in the tree_root, which is not marked as SHAREABLE. Reviewed-by:
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Josef Bacik authored
Currently we are locking the extent and dropping the extent cache for any inodes we truncate, unless they're in the tree log. We call this helper from: - truncate - evict - tree log - free space cache truncation For evict we've already dropped all of the extent cache for this inode once we've gotten here, and we're the only one accessing this inode, so this step is unnecessary. For the tree log code we already skip this part. Pull this work into the truncate path and the free space cache truncation path. Reviewed-by:
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Josef Bacik authored
This is an inode item related manipulation with a few vfs related adjustments. I'm going to remove the vfs related code from this helper and simplify it a lot, but I want those changes to be easily seen via git blame, so move this function now and then the simplification work can be done. Reviewed-by:
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Josef Bacik authored
We have a few helpers in inode-item.c, and I'm going to make a few changes to how we do truncate in the future, so break out these definitions into their own header file to trim down ctree.h some and make it easier to do the work on truncate in the future. Reviewed-by:
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Filipe Manana authored
The comment refers to the old extent buffer locking code, where we used to have custom locks that had blocking and spinning behaviour modes. That is not the case anymore, since we have transitioned to rw semaphores, so the comment does not offer any value anymore. Remove it. Reviewed-by:
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Filipe Manana authored
After calling split_leaf() we BUG_ON() if the returned value is greater than zero. However split_leaf() only returns 0, in case of success, or a negative value in case of an error. The reason for the BUG_ON() is that if we ever get a positive return value from split_leaf(), we can not simply propagate it to the callers of btrfs_search_slot(), as that would be interpreted as "key not found" and not as an error. That means it could result in callers ending up causing some potential silent corruption. So change the BUG_ON() to an ASSERT(), and in case assertions are disabled, produce a warning and set the return value to an error, to make it not possible to get into a silent corruption and having the error not noticed. Reviewed-by:
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Filipe Manana authored
There's quite a significant amount of code for doing the key search for a leaf at btrfs_search_slot(), with a couple labels and gotos in it, plus btrfs_search_slot() is already big enough. So move the logic that does the key search on a leaf into a new helper function. This makes it better organized, removing the need for the labels and the gotos, as well as reducing the indentation level and the size of btrfs_search_slot(). Reviewed-by:
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Filipe Manana authored
When inserting a key, we check if the write_lock_level is less than 1, and if so we set it to 1, release the path and retry the tree traversal. However that is unnecessary, because when ins_len is greater than 0, we know that write_lock_level can never be less than 1. The logic to retry is also buggy, because in case ins_len was decremented, due to an exact key match and the search is not meant for item extension (path->search_for_extension is 0), we retry without incrementing ins_len, which would make the next retry decrement it again by the same amount. So remove the check for write_lock_level being less than 1 and add an assertion to assert it's always >= 1. Reviewed-by:
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Filipe Manana authored
When inserting a new key, we release the write lock on the leaf's parent only after doing the binary search on the leaf. This is because if the key ends up at slot 0, we will have to update the key at slot 0 of the parent node. The same reasoning applies to any other upper level nodes when their slot is 0. We also need to keep the parent locked in case the leaf does not have enough free space to insert the new key/item, because in that case we will split the leaf and we will need to add a new key to the parent due to a new leaf resulting from the split operation. However if the leaf has enough space for the new key and the key does not end up at slot 0 of the leaf we could release our write lock on the parent before doing the binary search on the leaf to figure out the destination slot. That leads to reducing the amount of time other tasks are blocked waiting to lock the parent, therefore increasing parallelism when there are other tasks that are trying to access other leaves accessible through the same parent. This also applies to other upper nodes besides the immediate parent, when their slot is 0, since we keep locks on them until we figure out if the leaf slot is slot 0 or not. In fact, having the key ending at up slot 0 when is rare. Typically it only happens when the key is less than or equals to the smallest, the "left most", key of the entire btree, during a split attempt when we try to push to the right sibling leaf or when the caller just wants to update the item of an existing key. It's also very common that a leaf has enough space to insert a new key, since after a split we move about half of the keys from one into the new leaf. So unlock the parent, and any other upper level nodes, when during a key insertion we notice the key is greater then the first key in the leaf and the leaf has enough free space. After unlocking the upper level nodes, do the binary search using a low boundary of slot 1 and not slot 0, to figure out the slot where the key will be inserted (or where the key already is in case it exists and the caller wants to modify its item data). This extra comparison, with the first key, is cheap and the key is very likely already in a cache line because it immediately follows the header of the extent buffer and we have recently read the level field of the header (which in fact is the last field of the header). The following fs_mark test was run on a non-debug kernel (debian's default kernel config), with a 12 cores intel CPU, and using a NVMe device: $ cat run-fsmark.sh #!/bin/bash DEV=/dev/nvme0n1 MNT=/mnt/nvme0n1 MOUNT_OPTIONS="-o ssd" MKFS_OPTIONS="-O no-holes -R free-space-tree" FILES=100000 THREADS=$(nproc --all) FILE_SIZE=0 echo "performance" | \ tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor mkfs.btrfs -f $MKFS_OPTIONS $DEV mount $MOUNT_OPTIONS $DEV $MNT OPTS="-S 0 -L 10 -n $FILES -s $FILE_SIZE -t $THREADS -k" for ((i = 1; i <= $THREADS; i++)); do OPTS="$OPTS -d $MNT/d$i" done fs_mark $OPTS umount $MNT Before this change: FSUse% Count Size Files/sec App Overhead 0 1200000 0 165273.6 5958381 0 2400000 0 190938.3 6284477 0 3600000 0 181429.1 6044059 0 4800000 0 173979.2 6223418 0 6000000 0 139288.0 6384560 0 7200000 0 163000.4 6520083 1 8400000 0 57799.2 5388544 1 9600000 0 66461.6 5552969 2 10800000 0 49593.5 5163675 2 12000000 0 57672.1 4889398 After this change: FSUse% Count Size Files/sec App Overhead 0 1200000 0 167987.3 (+1.6%) 6272730 0 2400000 0 198563.9 (+4.0%) 6048847 0 3600000 0 197436.6 (+8.8%) 6163637 0 4800000 0 202880.7 (+16.6%) 6371771 1 6000000 0 167275.9 (+20.1%) 6556733 1 7200000 0 204051.2 (+25.2%) 6817091 1 8400000 0 69622.8 (+20.5%) 5525675 1 9600000 0 69384.5 (+4.4%) 5700723 1 10800000 0 61454.1 (+23.9%) 5363754 3 12000000 0 61908.7 (+7.3%) 5370196 Reviewed-by:
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