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* xfs: simplify log item descriptor trackingChristoph Hellwig2010-07-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | Currently we track log item descriptor belonging to a transaction using a complex opencoded chunk allocator. This code has been there since day one and seems to work around the lack of an efficient slab allocator. This patch replaces it with dynamically allocated log item descriptors from a dedicated slab pool, linked to the transaction by a linked list. This allows to greatly simplify the log item descriptor tracking to the point where it's just a couple hundred lines in xfs_trans.c instead of a separate file. The external API has also been simplified while we're at it - the xfs_trans_add_item and xfs_trans_del_item functions to add/ delete items from a transaction have been simplified to the bare minium, and the xfs_trans_find_item function is replaced with a direct dereference of the li_desc field. All debug code walking the list of log items in a transaction is down to a simple list_for_each_entry. Note that we could easily use a singly linked list here instead of the double linked list from list.h as the fastpath only does deletion from sequential traversal. But given that we don't have one available as a library function yet I use the list.h functions for simplicity. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com>
* xfs: drop dmapi hooksChristoph Hellwig2010-07-26
| | | | | | | | | | | | | | Dmapi support was never merged upstream, but we still have a lot of hooks bloating XFS for it, all over the fast pathes of the filesystem. This patch drops over 700 lines of dmapi overhead. If we'll ever get HSM support in mainline at least the namespace events can be done much saner in the VFS instead of the individual filesystem, so it's not like this is much help for future work. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com>
* xfs: Introduce delayed logging core codeDave Chinner2010-05-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The delayed logging code only changes in-memory structures and as such can be enabled and disabled with a mount option. Add the mount option and emit a warning that this is an experimental feature that should not be used in production yet. We also need infrastructure to track committed items that have not yet been written to the log. This is what the Committed Item List (CIL) is for. The log item also needs to be extended to track the current log vector, the associated memory buffer and it's location in the Commit Item List. Extend the log item and log vector structures to enable this tracking. To maintain the current log format for transactions with delayed logging, we need to introduce a checkpoint transaction and a context for tracking each checkpoint from initiation to transaction completion. This includes adding a log ticket for tracking space log required/used by the context checkpoint. To track all the changes we need an io vector array per log item, rather than a single array for the entire transaction. Using the new log vector structure for this requires two passes - the first to allocate the log vector structures and chain them together, and the second to fill them out. This log vector chain can then be passed to the CIL for formatting, pinning and insertion into the CIL. Formatting of the log vector chain is relatively simple - it's just a loop over the iovecs on each log vector, but it is made slightly more complex because we re-write the iovec after the copy to point back at the memory buffer we just copied into. This code also needs to pin log items. If the log item is not already tracked in this checkpoint context, then it needs to be pinned. Otherwise it is already pinned and we don't need to pin it again. The only other complexity is calculating the amount of new log space the formatting has consumed. This needs to be accounted to the transaction in progress, and the accounting is made more complex becase we need also to steal space from it for log metadata in the checkpoint transaction. Calculate all this at insert time and update all the tickets, counters, etc correctly. Once we've formatted all the log items in the transaction, attach the busy extents to the checkpoint context so the busy extents live until checkpoint completion and can be processed at that point in time. Transactions can then be freed at this point in time. Now we need to issue checkpoints - we are tracking the amount of log space used by the items in the CIL, so we can trigger background checkpoints when the space usage gets to a certain threshold. Otherwise, checkpoints need ot be triggered when a log synchronisation point is reached - a log force event. Because the log write code already handles chained log vectors, writing the transaction is trivial, too. Construct a transaction header, add it to the head of the chain and write it into the log, then issue a commit record write. Then we can release the checkpoint log ticket and attach the context to the log buffer so it can be called during Io completion to complete the checkpoint. We also need to allow for synchronising multiple in-flight checkpoints. This is needed for two things - the first is to ensure that checkpoint commit records appear in the log in the correct sequence order (so they are replayed in the correct order). The second is so that xfs_log_force_lsn() operates correctly and only flushes and/or waits for the specific sequence it was provided with. To do this we need a wait variable and a list tracking the checkpoint commits in progress. We can walk this list and wait for the checkpoints to change state or complete easily, an this provides the necessary synchronisation for correct operation in both cases. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
* xfs: Improve scalability of busy extent trackingDave Chinner2010-05-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When we free a metadata extent, we record it in the per-AG busy extent array so that it is not re-used before the freeing transaction hits the disk. This array is fixed size, so when it overflows we make further allocation transactions synchronous because we cannot track more freed extents until those transactions hit the disk and are completed. Under heavy mixed allocation and freeing workloads with large log buffers, we can overflow this array quite easily. Further, the array is sparsely populated, which means that inserts need to search for a free slot, and array searches often have to search many more slots that are actually used to check all the busy extents. Quite inefficient, really. To enable this aspect of extent freeing to scale better, we need a structure that can grow dynamically. While in other areas of XFS we have used radix trees, the extents being freed are at random locations on disk so are better suited to being indexed by an rbtree. So, use a per-AG rbtree indexed by block number to track busy extents. This incures a memory allocation when marking an extent busy, but should not occur too often in low memory situations. This should scale to an arbitrary number of extents so should not be a limitation for features such as in-memory aggregation of transactions. However, there are still situations where we can't avoid allocating busy extents (such as allocation from the AGFL). To minimise the overhead of such occurences, we need to avoid doing a synchronous log force while holding the AGF locked to ensure that the previous transactions are safely on disk before we use the extent. We can do this by marking the transaction doing the allocation as synchronous rather issuing a log force. Because of the locking involved and the ordering of transactions, the synchronous transaction provides the same guarantees as a synchronous log force because it ensures that all the prior transactions are already on disk when the synchronous transaction hits the disk. i.e. it preserves the free->allocate order of the extent correctly in recovery. By doing this, we avoid holding the AGF locked while log writes are in progress, hence reducing the length of time the lock is held and therefore we increase the rate at which we can allocate and free from the allocation group, thereby increasing overall throughput. The only problem with this approach is that when a metadata buffer is marked stale (e.g. a directory block is removed), then buffer remains pinned and locked until the log goes to disk. The issue here is that if that stale buffer is reallocated in a subsequent transaction, the attempt to lock that buffer in the transaction will hang waiting the log to go to disk to unlock and unpin the buffer. Hence if someone tries to lock a pinned, stale, locked buffer we need to push on the log to get it unlocked ASAP. Effectively we are trading off a guaranteed log force for a much less common trigger for log force to occur. Ideally we should not reallocate busy extents. That is a much more complex fix to the problem as it involves direct intervention in the allocation btree searches in many places. This is left to a future set of modifications. Finally, now that we track busy extents in allocated memory, we don't need the descriptors in the transaction structure to point to them. We can replace the complex busy chunk infrastructure with a simple linked list of busy extents. This allows us to remove a large chunk of code, making the overall change a net reduction in code size. Signed-off-by: Dave Chinner <david@fromorbit.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
* xfs: fix various typosMalcolm Parsons2009-03-29
| | | | | Signed-off-by: Malcolm Parsons <malcolm.parsons@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
* [XFS] Add ail pointer into log itemsDavid Chinner2008-10-30
| | | | | | | | | | | | | Add an xfs_ail pointer to log items so that the log items can reference the AIL directly during callbacks without needed a struct xfs_mount. SGI-PV: 988143 SGI-Modid: xfs-linux-melb:xfs-kern:32352a Signed-off-by: David Chinner <david@fromorbit.com> Signed-off-by: Lachlan McIlroy <lachlan@sgi.com> Signed-off-by: Christoph Hellwig <hch@infradead.org>
* [XFS] remove shouting-indirection macros from xfs_trans.hEric Sandeen2008-08-13
| | | | | | | | | | SGI-PV: 981498 SGI-Modid: xfs-linux-melb:xfs-kern:31758a Signed-off-by: Eric Sandeen <sandeen@sandeen.net> Signed-off-by: Niv Sardi <xaiki@sgi.com> Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
* [XFS] Remove unused arg from kmem_free()Denys Vlasenko2008-07-28
| | | | | | | | | | | | | | kmem_free() function takes (ptr, size) arguments but doesn't actually use second one. This patch removes size argument from all callsites. SGI-PV: 981498 SGI-Modid: xfs-linux-melb:xfs-kern:31050a Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Signed-off-by: David Chinner <dgc@sgi.com> Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
* [XFS] Fix up sparse warnings.David Chinner2008-02-07
| | | | | | | | | | | | These are mostly locking annotations, marking things static, casts where needed and declaring stuff in header files. SGI-PV: 971186 SGI-Modid: xfs-linux-melb:xfs-kern:30002a Signed-off-by: David Chinner <dgc@sgi.com> Signed-off-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
* [XFS] Portability changes: remove prdev, stick to one diagnosticNathan Scott2006-06-09
| | | | | | | | | interface. SGI-PV: 953338 SGI-Modid: xfs-linux-melb:xfs-kern:26103a Signed-off-by: Nathan Scott <nathans@sgi.com>
* return statement cleanup - kill pointless parenthesesJesper Juhl2006-01-14
| | | | | | | This patch removes pointless parentheses from return statements. Signed-off-by: Jesper Juhl <juhl-lkml@dif.dk> Signed-off-by: Adrian Bunk <bunk@stusta.de>
* [XFS] Update license/copyright notices to match the prefered SGINathan Scott2005-11-01
| | | | | | | | | boilerplate. SGI-PV: 913862 SGI-Modid: xfs-linux:xfs-kern:23903a Signed-off-by: Nathan Scott <nathans@sgi.com>
* [XFS] Remove xfs_macros.c, xfs_macros.h, rework headers a whole lot.Nathan Scott2005-11-01
| | | | | | | SGI-PV: 943122 SGI-Modid: xfs-linux:xfs-kern:23901a Signed-off-by: Nathan Scott <nathans@sgi.com>
* Linux-2.6.12-rc2v2.6.12-rc2Linus Torvalds2005-04-16
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!