- 06 Apr, 2023 40 commits
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Matthew Wilcox authored
Iterate once per folio, not once per page. Signed-off-by:
Matthew Wilcox (Oracle) <willy@infradead.org> Link: https://lore.kernel.org/r/20230324180129.1220691-27-willy@infradead.orgSigned-off-by:
Theodore Ts'o <tytso@mit.edu>
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Matthew Wilcox authored
Convert to the folio API, saving a few calls to compound_head(). Signed-off-by:
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Matthew Wilcox authored
All the callers now have a folio, so pass that in and operate on folios. Removes four calls to compound_head(). Signed-off-by:
Ritesh Harjani (IBM) <ritesh.list@gmail.com> Link: https://lore.kernel.org/r/20230324180129.1220691-25-willy@infradead.orgSigned-off-by:
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Matthew Wilcox authored
This definitely doesn't include support for large folios; there are all kinds of assumptions about the number of buffers attached to a folio. But it does remove several calls to compound_head(). Signed-off-by:
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Matthew Wilcox authored
Remove a few calls to compound_head(). Signed-off-by:
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Matthew Wilcox authored
Its one caller already uses a folio. Signed-off-by:
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Matthew Wilcox authored
Use folio APIs throughout. Saves many calls to compound_head(). Signed-off-by:
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Matthew Wilcox authored
Remove a call to compound_head(). Signed-off-by:
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Matthew Wilcox authored
Convert the incoming page to a folio to remove a few calls to compound_head(). Signed-off-by:
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Matthew Wilcox authored
Convert the incoming struct page to a folio. Replaces two implicit calls to compound_head() with one explicit call. Signed-off-by:
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Matthew Wilcox authored
Remove a lot of calls to compound_head(). Signed-off-by:
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Matthew Wilcox authored
Convert the incoming page to a folio so that we call compound_head() only once instead of seven times. Signed-off-by:
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Matthew Wilcox authored
All callers now have a folio, so pass it and use it. The folio may be large, although I doubt we'll want to use a large folio for an inline file. Signed-off-by:
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Matthew Wilcox authored
Saves a number of calls to compound_head(). Signed-off-by:
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Matthew Wilcox authored
Saves a number of calls to compound_head(). Signed-off-by:
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Matthew Wilcox authored
Saves a number of calls to compound_head(). Signed-off-by:
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Matthew Wilcox authored
Saves a number of calls to compound_head(). Signed-off-by:
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Matthew Wilcox authored
Use the folio API in this function, saves a few calls to compound_head(). Signed-off-by:
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Matthew Wilcox authored
The only caller now has a folio so pass it in directly and avoid the call to page_folio() at the beginning. Signed-off-by:
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Matthew Wilcox authored
All callers now have a folio so we can pass one in and use the folio APIs to support large folios as well as save instructions by eliminating a call to compound_head(). Signed-off-by:
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Matthew Wilcox authored
All callers now have a folio so we can pass one in and use the folio APIs to support large folios as well as save instructions by eliminating calls to compound_head(). Signed-off-by:
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Matthew Wilcox authored
The page/folio is only used to extract the buffers, so this is a simple change. Signed-off-by:
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Matthew Wilcox authored
Prepare ext4 to support large folios in the page writeback path. Also set the actual error in the mapping, not just -EIO. Signed-off-by:
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Matthew Wilcox authored
Remove several calls to compound_head() and the last caller of set_page_writeback_keepwrite(), so remove the wrapper too. Also export bio_add_folio() as this is the first caller from a module. Signed-off-by:
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Matthew Wilcox authored
fscrypt_is_bounce_folio() is the equivalent of fscrypt_is_bounce_page() and fscrypt_pagecache_folio() is the equivalent of fscrypt_pagecache_page(). Signed-off-by:
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Matthew Wilcox authored
This particular combination of flags is used by most filesystems in their ->write_begin method, although it does find use in a few other places. Before folios, it warranted its own function (grab_cache_page_write_begin()), but I think that just having specialised flags is enough. It certainly helps the few places that have been converted from grab_cache_page_write_begin() to __filemap_get_folio(). Signed-off-by:
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Ojaswin Mujoo authored
Earlier, inode PAs were stored in a linked list. This caused a need to periodically trim the list down inorder to avoid growing it to a very large size, as this would severly affect performance during list iteration. Recent patches changed this list to an rbtree, and since the tree scales up much better, we no longer need to have the trim functionality, hence remove it. Signed-off-by:
Ojaswin Mujoo <ojaswin@linux.ibm.com> Reviewed-by:
Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/c409addceaa3ade4b40328e28e3b54b2f259689e.1679731817.git.ojaswin@linux.ibm.comSigned-off-by:
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Ojaswin Mujoo authored
Currently, the kernel uses i_prealloc_list to hold all the inode preallocations. This is known to cause degradation in performance in workloads which perform large number of sparse writes on a single file. This is mainly because functions like ext4_mb_normalize_request() and ext4_mb_use_preallocated() iterate over this complete list, resulting in slowdowns when large number of PAs are present. Patch 27bc446e partially fixed this by enforcing a limit of 512 for the inode preallocation list and adding logic to continually trim the list if it grows above the threshold, however our testing revealed that a hardcoded value is not suitable for all kinds of workloads. To optimize this, add an rbtree to the inode and hold the inode preallocations in this rbtree. This will make iterating over inode PAs faster and scale much better than a linked list. Additionally, we also had to remove the LRU logic that was added during trimming of the list (in ext4_mb_release_context()) as it will add extra overhead in rbtree. The discards now happen in the lowest-logical-offset-first order. ** Locking notes ** With the introduction of rbtree to maintain inode PAs, we can't use RCU to walk the tree for searching since it can result in partial traversals which might miss some nodes(or entire subtrees) while discards happen in parallel (which happens under a lock). Hence this patch converts the ei->i_prealloc_lock spin_lock to rw_lock. Almost all the codepaths that read/modify the PA rbtrees are protected by the higher level inode->i_data_sem (except ext4_mb_discard_group_preallocations() and ext4_clear_inode()) IIUC, the only place we need lock protection is when one thread is reading "searching" the PA rbtree (earlier protected under rcu_read_lock()) and another is "deleting" the PAs in ext4_mb_discard_group_preallocations() function (which iterates all the PAs using the grp->bb_prealloc_list and deletes PAs from the tree without taking any inode lock (i_data_sem)). So, this patch converts all rcu_read_lock/unlock() paths for inode list PA to use read_lock() and all places where we were using ei->i_prealloc_lock spinlock will now be using write_lock(). Note that this makes the fast path (searching of the right PA e.g. ext4_mb_use_preallocated() or ext4_mb_normalize_request()), now use read_lock() instead of rcu_read_lock/unlock(). Ths also will now block due to slow discard path (ext4_mb_discard_group_preallocations()) which uses write_lock(). But this is not as bad as it looks. This is because - 1. The slow path only occurs when the normal allocation failed and we can say that we are low on disk space. One can argue this scenario won't be much frequent. 2. ext4_mb_discard_group_preallocations(), locks and unlocks the rwlock for deleting every individual PA. This gives enough opportunity for the fast path to acquire the read_lock for searching the PA inode list. Suggested-by:
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Ojaswin Mujoo authored
** Splitting pa->pa_inode_list ** Currently, we use the same pa->pa_inode_list to add a pa to either the inode preallocation list or the locality group preallocation list. For better clarity, split this list into a union of 2 list_heads and use either of the them based on the type of pa. ** Splitting pa->pa_obj_lock ** Currently, pa->pa_obj_lock is either assigned &ei->i_prealloc_lock for inode PAs or lg_prealloc_lock for lg PAs, and is then used to lock the lists containing these PAs. Make the distinction between the 2 PA types clear by changing this lock to a union of 2 locks. Explicitly use the pa_lock_node.inode_lock for inode PAs and pa_lock_node.lg_lock for lg PAs. This patch is required so that the locality group preallocation code remains the same as in upcoming patches we are going to make changes to inode preallocation code to move from list to rbtree based implementation. This patch also makes it easier to review the upcoming patches. There are no functional changes in this patch. Suggested-by:
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Ojaswin Mujoo authored
When the length of best extent found is less than the length of goal extent we need to make sure that the best extent atleast covers the start of the original request. This is done by adjusting the ac_b_ex.fe_logical (logical start) of the extent. While doing so, the current logic sometimes results in the best extent's logical range overflowing the goal extent. Since this best extent is later added to the inode preallocation list, we have a possibility of introducing overlapping preallocations. This is discussed in detail here [1]. As per Jan's suggestion, to fix this, replace the existing logic with the below logic for adjusting best extent as it keeps fragmentation in check while ensuring logical range of best extent doesn't overflow out of goal extent: 1. Check if best extent can be kept at end of goal range and still cover original start. 2. Else, check if best extent can be kept at start of goal range and still cover original start. 3. Else, keep the best extent at start of original request. Also, add a few extra BUG_ONs that might help catch errors faster. [1] https://lore.kernel.org/r/Y+OGkVvzPN0RMv0O@li-bb2b2a4c-3307-11b2-a85c-8fa5c3a69313.ibm.comSuggested-by:
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Ojaswin Mujoo authored
Abstract out the logic of fixing PA overlaps in ext4_mb_normalize_request to improve readability of code. This also makes it easier to make changes to the overlap logic in future. There are no functional changes in this patch Signed-off-by:
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Ojaswin Mujoo authored
Abstract out the logic to double check for overlaps in normalize_pa to a separate function. Since there has been no reports in past where we have seen any overlaps which hits this bug_on(), in future we can consider calling this function under "#ifdef AGGRESSIVE_CHECK" only. There are no functional changes in this patch Signed-off-by:
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Ojaswin Mujoo authored
Change some variable names to be more consistent and refactor some of the code to make it easier to read. There are no functional changes in this patch Signed-off-by:
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Ojaswin Mujoo authored
This patch makes the following changes: * Rename ext4_mb_pa_free to ext4_mb_pa_put_free to better reflect its purpose * Add new ext4_mb_pa_free() which only handles freeing * Refactor ext4_mb_pa_callback() to use ext4_mb_pa_free() There are no functional changes in this patch Signed-off-by:
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Ojaswin Mujoo authored
If we come across a PA that matches the logical offset but is unable to satisfy a non-extent file due to its physical start being higher than that supported by non extent files, then simply stop searching for another PA and break out of loop. This is because, since PAs don't overlap, we won't be able to find another inode PA which can satisfy the original request. Signed-off-by:
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Theodore Ts'o authored
In cases where we have an obvious way of continuing, let's use WARN_RATELIMITED() instead of BUG_ON(). Signed-off-by: -
Kemeng Shi authored
Result of EXT4_SB(ac->ac_sb) is already stored in sbi at beginning of ext4_mb_normalize_request. Use sbi instead of EXT4_SB(ac->ac_sb) to remove unnecessary pointer dereference. Signed-off-by:
Kemeng Shi <shikemeng@huaweicloud.com> Reviewed-by:
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Kemeng Shi authored
pa_plen -> pa_len pa_start -> pa_pstart Signed-off-by:
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Kemeng Shi authored
We try to allocate a block from goal in ext4_mb_new_blocks_simple. We only need get blkoff in first group with goal and set blkoff to 0 for the rest groups. Signed-off-by:
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Kemeng Shi authored
Just remove comment code in ext4_discard_preallocations. Signed-off-by:
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