The existing per-cpu superblock counter code uses the global superblock
spin lock when we approach ENOSPC for global synchronisation. On larger
machines than this code was originally tested on this can still get
catastrophic spinlock contention due increasing rebalance frequency near
ENOSPC.
By introducing a sleeping lock that is used to serialise balances and
modifications near ENOSPC we prevent contention from needlessly from
wasting the CPU time of potentially hundreds of CPUs.
To reduce the number of balances occuring, we separate the need rebalance
case from the slow allocate case. Now, a counter running dry will trigger
a rebalance during which counters are disabled. Any thread that sees a
disabled counter enters a different path where it waits on the new mutex.
When it gets the new mutex, it checks if the counter is disabled. If the
counter is disabled, then we _know_ that we have to use the global counter
and lock and it is safe to do so immediately. Otherwise, we drop the mutex
and go back to trying the per-cpu counters which we know were re-enabled.
SGI-PV: 952227
SGI-Modid: xfs-linux-melb:xfs-kern:27612a
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Signed-off-by: Tim Shimmin <tes@sgi.com>
the range spanned by modifications to the in-core extent map. Add
XFS_BUNMAPI() and XFS_SWAP_EXTENTS() macros that call xfs_bunmapi() and
xfs_swap_extents() via the ioops vector. Change all calls that may modify
the in-core extent map for the data fork to go through the ioops vector.
This allows a cache of extent map data to be kept in sync.
SGI-PV: 947615
SGI-Modid: xfs-linux-melb:xfs-kern:209226a
Signed-off-by: Olaf Weber <olaf@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>
a preēmpt counter overflow at 256p and above. Change the exclusion
mechanism to use atomic bit operations and busy wait loops to emulate the
spin lock exclusion mechanism but without the preempt count issues.
SGI-PV: 950027
SGI-Modid: xfs-linux-melb:xfs-kern:25338a
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>
registering a notifier callback that listens to CPU up/down events to
modify the counters appropriately.
SGI-PV: 949726
SGI-Modid: xfs-linux-melb:xfs-kern:25214a
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>
threads, the incore superblock lock becomes the limiting factor for
buffered write throughput. Make the contended fields in the incore
superblock use per-cpu counters so that there is no global lock to limit
scalability.
SGI-PV: 946630
SGI-Modid: xfs-linux-melb:xfs-kern:25106a
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>
actually use it. Kill this dead code. Signed-off-by: Christoph Hellwig
<hch@lst.de>
SGI-PV: 904196
SGI-Modid: xfs-linux-melb:xfs-kern:25086a
Signed-off-by: Nathan Scott <nathans@sgi.com>
This patch switches XFS over to use the new mutex code directly as
opposed to the previous workaround patch I posted earlier that avoided
the namespace clash by forcing it back to semaphores. This falls in the
'works for me<tm>' category.
Signed-off-by: Jes Sorensen <jes@trained-monkey.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
the data/attr forks now grow up/down from either end of the literal area,
rather than dividing the literal area into two chunks and growing both
upward. Means we can now make much more efficient use of the attribute
space, incl. fitting DMF attributes inline in 256 byte inodes, and large
jumps in dbench3 performance numbers. It is self enabling, but can be
forced on/off via the attr2/noattr2 mount options.
SGI-PV: 941645
SGI-Modid: xfs-linux:xfs-kern:23837a
Signed-off-by: Nathan Scott <nathans@sgi.com>
filesystems to expose the filesystem stripe width in stat(2) rather than
the page cache size. This allows applications requiring high bandwidth to
easily determine the optimum I/O size for the underlying filesystem. The
default is to report the page cache size (i.e. "nolargeio").
SGI-PV: 942818
SGI-Modid: xfs-linux:xfs-kern:23830a
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>
writes. In addition flush the disk cache on fsync if the sync cached
operation didn't sync the log to disk (this requires some additional
bookeping in the transaction and log code). If the device doesn't claim to
support barriers, the filesystem has an extern log volume or the trial
superblock write with barriers enabled failed we disable barriers and
print a warning. We should probably fail the mount completely, but that
could lead to nasty boot failures for the root filesystem. Not enabled by
default yet, needs more destructive testing first.
SGI-PV: 912426
SGI-Modid: xfs-linux:xfs-kern:198723a
Signed-off-by: Christoph Hellwig <hch@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>
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!
David Chinner