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path: root/fs/xfs/xfs_ialloc.c
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2007-07-14[XFS] Lazy Superblock CountersDavid Chinner
When we have a couple of hundred transactions on the fly at once, they all typically modify the on disk superblock in some way. create/unclink/mkdir/rmdir modify inode counts, allocation/freeing modify free block counts. When these counts are modified in a transaction, they must eventually lock the superblock buffer and apply the mods. The buffer then remains locked until the transaction is committed into the incore log buffer. The result of this is that with enough transactions on the fly the incore superblock buffer becomes a bottleneck. The result of contention on the incore superblock buffer is that transaction rates fall - the more pressure that is put on the superblock buffer, the slower things go. The key to removing the contention is to not require the superblock fields in question to be locked. We do that by not marking the superblock dirty in the transaction. IOWs, we modify the incore superblock but do not modify the cached superblock buffer. In short, we do not log superblock modifications to critical fields in the superblock on every transaction. In fact we only do it just before we write the superblock to disk every sync period or just before unmount. This creates an interesting problem - if we don't log or write out the fields in every transaction, then how do the values get recovered after a crash? the answer is simple - we keep enough duplicate, logged information in other structures that we can reconstruct the correct count after log recovery has been performed. It is the AGF and AGI structures that contain the duplicate information; after recovery, we walk every AGI and AGF and sum their individual counters to get the correct value, and we do a transaction into the log to correct them. An optimisation of this is that if we have a clean unmount record, we know the value in the superblock is correct, so we can avoid the summation walk under normal conditions and so mount/recovery times do not change under normal operation. One wrinkle that was discovered during development was that the blocks used in the freespace btrees are never accounted for in the AGF counters. This was once a valid optimisation to make; when the filesystem is full, the free space btrees are empty and consume no space. Hence when it matters, the "accounting" is correct. But that means the when we do the AGF summations, we would not have a correct count and xfs_check would complain. Hence a new counter was added to track the number of blocks used by the free space btrees. This is an *on-disk format change*. As a result of this, lazy superblock counters are a mkfs option and at the moment on linux there is no way to convert an old filesystem. This is possible - xfs_db can be used to twiddle the right bits and then xfs_repair will do the format conversion for you. Similarly, you can convert backwards as well. At some point we'll add functionality to xfs_admin to do the bit twiddling easily.... SGI-PV: 964999 SGI-Modid: xfs-linux-melb:xfs-kern:28652a Signed-off-by: David Chinner <dgc@sgi.com> Signed-off-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Tim Shimmin <tes@sgi.com>
2007-02-10[XFS] Keep stack usage down for 4k stacks by using noinline.David Chinner
gcc-4.1 and more recent aggressively inline static functions which increases XFS stack usage by ~15% in critical paths. Prevent this from occurring by adding noinline to the STATIC definition. Also uninline some functions that are too large to be inlined and were causing problems with CONFIG_FORCED_INLINING=y. Finally, clean up all the different users of inline, __inline and __inline__ and put them under one STATIC_INLINE macro. For debug kernels the STATIC_INLINE macro uninlines those functions. SGI-PV: 957159 SGI-Modid: xfs-linux-melb:xfs-kern:27585a Signed-off-by: David Chinner <dgc@sgi.com> Signed-off-by: David Chatterton <chatz@sgi.com> Signed-off-by: Tim Shimmin <tes@sgi.com>
2006-09-28[XFS] Remove last bulkstat false-positives with debug kernels.Nathan Scott
SGI-PV: 953819 SGI-Modid: xfs-linux-melb:xfs-kern:26628a Signed-off-by: Nathan Scott <nathans@sgi.com> Signed-off-by: Tim Shimmin <tes@sgi.com>
2006-09-28[XFS] use NULL for pointer initialisation instead of zero-cast-to-ptrNathan Scott
SGI-PV: 954580 SGI-Modid: xfs-linux-melb:xfs-kern:26562a Signed-off-by: Nathan Scott <nathans@sgi.com> Signed-off-by: Tim Shimmin <tes@sgi.com>
2006-09-28[XFS] endianess annotations for xfs_inobt_rec_t / xfs_inobt_key_tChristoph Hellwig
SGI-PV: 954580 SGI-Modid: xfs-linux-melb:xfs-kern:26556a Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nathan Scott <nathans@sgi.com> Signed-off-by: Tim Shimmin <tes@sgi.com>
2006-06-20[XFS] Remove version 1 directory code. Never functioned on Linux, justNathan Scott
pure bloat. SGI-PV: 952969 SGI-Modid: xfs-linux-melb:xfs-kern:26251a Signed-off-by: Nathan Scott <nathans@sgi.com>
2006-06-09[XFS] Fix up debug code so that bulkstat wont generate thousands ofNathan Scott
fsstress warnings. SGI-PV: 904196 SGI-Modid: xfs-linux-melb:xfs-kern:26111a Signed-off-by: Nathan Scott <nathans@sgi.com>
2006-04-11[XFS] Fix a problem in aligning inode allocations to stripe unitNathan Scott
boundaries. SGI-PV: 951862 SGI-Modid: xfs-linux-melb:xfs-kern:25726a Signed-off-by: Nathan Scott <nathans@sgi.com>
2006-03-29[XFS] A change to inode chunk allocation to try allocating the new chunkGlen Overby
contiguous with the most recently allocated chunk. On a striped filesystem, this will fill a stripe unit with inodes before allocating new inodes in another stripe unit. SGI-PV: 951416 SGI-Modid: xfs-linux-melb:xfs-kern:208488a Signed-off-by: Glen Overby <overby@sgi.com> Signed-off-by: Nathan Scott <nathans@sgi.com>
2006-03-29[XFS] We really suck at spulling. Thanks to Chris Pascoe for fixing allNathan Scott
these typos. SGI-PV: 904196 SGI-Modid: xfs-linux-melb:xfs-kern:25539a Signed-off-by: Nathan Scott <nathans@sgi.com>
2006-03-14[XFS] Dynamically allocate the xfs_dinode_core_t structure to reduce ourNathan Scott
stack footprint in xfs_ialloc_ag_alloc. SGI-PV: 947312 SGI-Modid: xfs-linux-melb:xfs-kern:25420a Signed-off-by: Nathan Scott <nathans@sgi.com>
2005-11-02[XFS] Endianess annotations for various allocator data structuresChristoph Hellwig
SGI-PV: 943272 SGI-Modid: xfs-linux:xfs-kern:201006a Signed-off-by: Christoph Hellwig <hch@sgi.com> Signed-off-by: Nathan Scott <nathans@sgi.com>
2005-11-02[XFS] Update license/copyright notices to match the prefered SGINathan Scott
boilerplate. SGI-PV: 913862 SGI-Modid: xfs-linux:xfs-kern:23903a Signed-off-by: Nathan Scott <nathans@sgi.com>
2005-11-02[XFS] Remove xfs_macros.c, xfs_macros.h, rework headers a whole lot.Nathan Scott
SGI-PV: 943122 SGI-Modid: xfs-linux:xfs-kern:23901a Signed-off-by: Nathan Scott <nathans@sgi.com>
2005-11-02[XFS] Add format checking to cmn_err and icmn_errChristoph Hellwig
SGI-PV: 942243 SGI-Modid: xfs-linux:xfs-kern:198658a Signed-off-by: Christoph Hellwig <hch@sgi.com> Signed-off-by: Nathan Scott <nathans@sgi.com>
2005-04-16Linux-2.6.12-rc2Linus Torvalds
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!