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  1. 30 10月, 2008 1 次提交
    • D
      [XFS] Use a cursor for AIL traversal. · 27d8d5fe
      由 David Chinner 提交于 
      To replace the current generation number ensuring sanity of the AIL
traversal, replace it with an external cursor that is linked to the AIL.

Basically, we store the next item in the cursor whenever we want to drop
the AIL lock to do something to the current item. When we regain the lock.
the current item may already be free, so we can't reference it, but the
next item in the traversal is already held in the cursor.

When we move or delete an object, we search all the active cursors and if
there is an item match we clear the cursor(s) that point to the object.
This forces the traversal to restart transparently.

We don't invalidate the cursor on insert because the cursor still points
to a valid item. If the intem is inserted between the current item and the
cursor it does not matter; the traversal is considered to be past the
insertion point so it will be picked up in the next traversal.

Hence traversal restarts pretty much disappear altogether with this method
of traversal, which should substantially reduce the overhead of pushing on
a busy AIL.

Version 2 o add restart logic o comment cursor interface o minor cleanups

SGI-PV: 988143

SGI-Modid: xfs-linux-melb:xfs-kern:32347a
Signed-off-by: NDavid Chinner <david@fromorbit.com>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
      27d8d5fe
  3. 11 10月, 2008 1 次提交
  5. 17 9月, 2008 2 次提交
  7. 13 8月, 2008 4 次提交
  9. 28 7月, 2008 3 次提交
  11. 12 7月, 2008 1 次提交
    • D
      Fix reference counting race on log buffers · 49641f1a
      由 Dave Chinner 提交于 
      When we release the iclog, we do an atomic_dec_and_lock to determine if
we are the last reference and need to trigger update of log headers and
writeout.  However, in xlog_state_get_iclog_space() we also need to
check if we have the last reference count there.  If we do, we release
the log buffer, otherwise we decrement the reference count.

But the compare and decrement in xlog_state_get_iclog_space() is not
atomic, so both places can see a reference count of 2 and neither will
release the iclog.  That leads to a filesystem hang.

Close the race by replacing the atomic_read() and atomic_dec() pair with
atomic_add_unless() to ensure that they are executed atomically.
Signed-off-by: NDave Chinner <david@fromorbit.com>
Reviewed-by: NTim Shimmin <tes@sgi.com>
Tested-by: NEric Sandeen <sandeen@sandeen.net>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      49641f1a
  13. 18 4月, 2008 9 次提交
  15. 10 4月, 2008 1 次提交
  17. 14 2月, 2008 1 次提交
  19. 07 2月, 2008 10 次提交
    • D
      [XFS] Move AIL pushing into it's own thread · 249a8c11
      由 David Chinner 提交于 
      When many hundreds to thousands of threads all try to do simultaneous
transactions and the log is in a tail-pushing situation (i.e. full), we
can get multiple threads walking the AIL list and contending on the AIL
lock.

The AIL push is, in effect, a simple I/O dispatch algorithm complicated by
the ordering constraints placed on it by the transaction subsystem. It
really does not need multiple threads to push on it - even when only a
single CPU is pushing the AIL, it can push the I/O out far faster that
pretty much any disk subsystem can handle.

So, to avoid contention problems stemming from multiple list walkers, move
the list walk off into another thread and simply provide a "target" to
push to. When a thread requires a push, it sets the target and wakes the
push thread, then goes to sleep waiting for the required amount of space
to become available in the log.

This mechanism should also be a lot fairer under heavy load as the waiters
will queue in arrival order, rather than queuing in "who completed a push
first" order.

Also, by moving the pushing to a separate thread we can do more
effectively overload detection and prevention as we can keep context from
loop iteration to loop iteration. That is, we can push only part of the
list each loop and not have to loop back to the start of the list every
time we run. This should also help by reducing the number of items we try
to lock and/or push items that we cannot move.

Note that this patch is not intended to solve the inefficiencies in the
AIL structure and the associated issues with extremely large list
contents. That needs to be addresses separately; parallel access would
cause problems to any new structure as well, so I'm only aiming to isolate
the structure from unbounded parallelism here.

SGI-PV: 972759
SGI-Modid: xfs-linux-melb:xfs-kern:30371a
Signed-off-by: NDavid Chinner <dgc@sgi.com>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>
      249a8c11
    • T
      [XFS] Remove the BPCSHIFT and NB* based macros from XFS. · e6a4b37f
      由 Tim Shimmin 提交于 
      The BPCSHIFT based macros, btoc*, ctob*, offtoc* and ctooff are either not
used or don't need to be used. The NDPP, NDPP, NBBY macros don't need to
be used but instead are replaced directly by PAGE_SIZE and PAGE_CACHE_SIZE
where appropriate. Initial patch and motivation from Nicolas Kaiser.

SGI-PV: 971186
SGI-Modid: xfs-linux-melb:xfs-kern:30096a
Signed-off-by: NTim Shimmin <tes@sgi.com>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>
      e6a4b37f
    • N
      [XFS] Remove bogus assert · f7b7c367
      由 Niv Sardi 提交于 
      This assert is bogus. We can have a forced shutdown occur
between the check for the XLOG_FORCED_SHUTDOWN and the ASSERT. Also, the
logging system shouldn't care about the state of XFS_FORCED_SHUTDOWN, it
should only check XLOG_FORCED_SHUTDOWN. The logging system has it's own
forced shutdown flag so, for the case of a forced shutdown that's not due
to a logging error, we can flush the log.

SGI-PV: 972985
SGI-Modid: xfs-linux-melb:xfs-kern:30029a
Signed-off-by: NNiv Sardi <xaiki@sgi.com>
Signed-off-by: NDavid Chinner <dgc@sgi.com>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>
      f7b7c367
    • D
      [XFS] Fix up sparse warnings. · a8272ce0
      由 David Chinner 提交于 
      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: NDavid Chinner <dgc@sgi.com>
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>
      a8272ce0
    • C
      [XFS] xlog_rec_header/xlog_rec_ext_header endianess annotations · b53e675d
      由 Christoph Hellwig 提交于 
      Mostly trivial conversion with one exceptions: h_num_logops was kept in
native endian previously and only converted to big endian in xlog_sync,
but we always keep it big endian now. With todays cpus fast byteswap
instructions that's not an issue but the new variant keeps the code clean
and maintainable.

SGI-PV: 971186
SGI-Modid: xfs-linux-melb:xfs-kern:29821a
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>
Signed-off-by: NTim Shimmin <tes@sgi.com>
      b53e675d
    • C
      [XFS] clean up some xfs_log_priv.h macros · 67fcb7bf
      由 Christoph Hellwig 提交于 
      - the various assign lsn macros are replaced by a single inline,
xlog_assign_lsn, which is equivalent to ASSIGN_ANY_LSN_HOST except
for a more sane calling convention. ASSIGN_LSN_DISK is replaced
by xlog_assign_lsn and a manual bytespap, and ASSIGN_LSN by the same,
except we pass the cycle and block arguments explicitly instead of a
log paramter. The latter two variants only had 2, respectively one
user anyway.
- the GET_CYCLE is replaced by a xlog_get_cycle inline with exactly the
same calling conventions.
- GET_CLIENT_ID is replaced by xlog_get_client_id which leaves away
the unused arch argument. Instead of conditional defintions
depending on host endianess we now do an unconditional swap and shift
then, which generates equal code.
- the unused XLOG_SET macro is removed.

SGI-PV: 971186
SGI-Modid: xfs-linux-melb:xfs-kern:29820a
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>
Signed-off-by: NTim Shimmin <tes@sgi.com>
      67fcb7bf
    • C
      [XFS] clean up some xfs_log_priv.h macros · 03bea6fe
      由 Christoph Hellwig 提交于 
      - the various assign lsn macros are replaced by a single inline,
xlog_assign_lsn, which is equivalent to ASSIGN_ANY_LSN_HOST except
for a more sane calling convention. ASSIGN_LSN_DISK is replaced
by xlog_assign_lsn and a manual bytespap, and ASSIGN_LSN by the same,
except we pass the cycle and block arguments explicitly instead of a
log paramter. The latter two variants only had 2, respectively one
user anyway.
- the GET_CYCLE is replaced by a xlog_get_cycle inline with exactly the
same calling conventions.
- GET_CLIENT_ID is replaced by xlog_get_client_id which leaves away
the unused arch argument. Instead of conditional defintions
depending on host endianess we now do an unconditional swap and shift
then, which generates equal code.
- the unused XLOG_SET macro is removed.

SGI-PV: 971186
SGI-Modid: xfs-linux-melb:xfs-kern:29819a
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>
Signed-off-by: NTim Shimmin <tes@sgi.com>
      03bea6fe
    • E
      [XFS] Remove spin.h · 007c61c6
      由 Eric Sandeen 提交于 
      remove spinlock init abstraction macro in spin.h, remove the callers, and
remove the file. Move no-op spinlock_destroy to xfs_linux.h Cleanup
spinlock locals in xfs_mount.c

SGI-PV: 970382
SGI-Modid: xfs-linux-melb:xfs-kern:29751a
Signed-off-by: NEric Sandeen <sandeen@sandeen.net>
Signed-off-by: NDonald Douwsma <donaldd@sgi.com>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>
Signed-off-by: NTim Shimmin <tes@sgi.com>
      007c61c6
    • E
      [XFS] Unwrap GRANT_LOCK. · c8b5ea28
      由 Eric Sandeen 提交于 
      Un-obfuscate GRANT_LOCK, remove GRANT_LOCK->mutex_lock->spin_lock macros,
call spin_lock directly, remove extraneous cookie holdover from old xfs
code, and change lock type to spinlock_t.

SGI-PV: 970382
SGI-Modid: xfs-linux-melb:xfs-kern:29741a
Signed-off-by: NEric Sandeen <sandeen@sandeen.net>
Signed-off-by: NDonald Douwsma <donaldd@sgi.com>
Signed-off-by: NTim Shimmin <tes@sgi.com>
      c8b5ea28
    • E
      [XFS] Unwrap LOG_LOCK. · b22cd72c
      由 Eric Sandeen 提交于 
      Un-obfuscate LOG_LOCK, remove LOG_LOCK->mutex_lock->spin_lock macros, call
spin_lock directly, remove extraneous cookie holdover from old xfs code,
and change lock type to spinlock_t.

SGI-PV: 970382
SGI-Modid: xfs-linux-melb:xfs-kern:29740a
Signed-off-by: NEric Sandeen <sandeen@sandeen.net>
Signed-off-by: NDonald Douwsma <donaldd@sgi.com>
Signed-off-by: NTim Shimmin <tes@sgi.com>
      b22cd72c
  21. 16 10月, 2007 2 次提交
  23. 15 10月, 2007 2 次提交
  25. 05 9月, 2007 1 次提交
  27. 14 7月, 2007 2 次提交
    • D
      [XFS] Lazy Superblock Counters · 92821e2b
      由 David Chinner 提交于 
      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: NDavid Chinner <dgc@sgi.com>
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NTim Shimmin <tes@sgi.com>
      92821e2b
    • D
      [XFS] Fix vmalloc leak on mount/unmount. · 511105b3
      由 David Chinner 提交于 
      When setting the length of the iclogbuf to write out we should just be
changing the desired byte count rather completely reassociating the buffer
memory with the buffer. Reassociating the buffer memory changes the
apparent length of the buffer and hence when we free the buffer, we don't
free all the vmap()d space we originally allocated.

SGI-PV: 964983
SGI-Modid: xfs-linux-melb:xfs-kern:28640a
Signed-off-by: NDavid Chinner <dgc@sgi.com>
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NTim Shimmin <tes@sgi.com>
      511105b3