This patch improves redability of the code responsible for trying to find
a node with enough SPUs not committed to other affinity gangs.

An additional check is also added, to avoid taking into account gangs that
have no SPU affinity.
Signed-off-by: NAndre Detsch <adetsch@br.ibm.com>
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>

No need to zero the entire buffer, just the head and tail indices.
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>

With most file readers (eg cat, dd), reading a context's regs file will
result in two reads: the first to read the data, and the second to
return EOF. Because each read performs a spu_acquire_saved, we end up
descheduling and re-scheduling the context twice.

This change does a simple check to see if we'd return EOF before
calling spu_acquire_saved(), saving the extra schedule operation.
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>

Currently, read() on the sputrace log will block until the read buffer
is full. This makes it difficult to retrieve the end of the buffer, as
the user will need to read with the right-sized buffer.

In a similar method as 91553a1b5e0df006a3573a88d98ee7cd48a3818a, this
change makes the switch_log return if there has already been data
read.
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>

Currently, we use ctx->mapping_lock and ctx->switch_log->lock for the
context switch log. The mapping lock only prevents concurrent open()s,
so we require the switch_lock->lock for reads.

Since writes to the switch log buffer occur on context switches, we're
better off synchronising with the state_mutex, which is held during a
switch. Since we're serialised througout the buffer reads and writes,
we can use the state mutex to protect open and release too, and
can now kfree() the log buffer on release. This allows us to perform
the switch log notify without taking any extra locks.

Because the buffer is only present while the file is open, we can use
it to prevent multiple simultaneous openers.
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>

Currently, read() on the sputrace buffer will only return data when
the user buffer is exhausted. This may mean that we never see the
end of the event log, unless we read() with exactly the right-sized
buffer.

This change makes sputrace_read not block if we have data ready to
return.
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>

Currently, sputrace will start logging to the event buffer before the
log buffer has been open()ed. This results in a heap of "lost samples"
warnings if the sputrace file hasn't yet been opened.

Since the buffer is reset on open() anyway, there's no need to enable
logging when no-one has opened the log.

Because open clears the log, make it return EBUSY for mutliple open
calls.
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>

This is a much better version of a previous patch to make the parser
tables constant. Rather than changing the typedef, we put the "const" in
all the various places where its required, allowing the __initconst
exception for nfsroot which was the cause of the previous trouble.

This was posted for review some time ago and I believe its been in -mm
since then.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>
Cc: Alexander Viro <aviro@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

A mutex_unlock(&gang->aff_mutex) in spufs_create_context() is missing
in case spufs_context_open() fails.  As a result, spu_create syscall
and spu_get_idle() may block.

This patch adds the mutex_unlock.
Signed-off-by: NKou Ishizaki <kou.ishizaki@toshiba.co.jp>
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>
Acked-by: NAndre Detsch <adetsch@br.ibm.com>

Style change: use inc_nlink instead of incrementing i_nlink directly
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>

Currently, an empty spufs root inode has nlink count of 1. However,
the directory has two links; / -> spu and /spu/ -> .

This change increments the link count of the root inode in spufs.
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>

We currently have a race when scheduling a context to a SPE -
after we have found a runnable context in spusched_tick, the same
context may have been scheduled by spu_activate().

This may result in a panic if we try to unschedule a context that has
been freed in the meantime.

This change exits spu_schedule() if the context has already been
scheduled, so we don't end up scheduling it twice.
Signed-off-by: NAndre Detsch <adetsch@br.ibm.com>
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>

We currently have a race for a free SPE. With one thread doing a
spu_yield(), and another doing a spu_activate():

thread 1				thread 2
spu_yield(oldctx)			spu_activate(ctx)
  __spu_deactivate(oldctx)
  spu_unschedule(oldctx, spu)
  spu->alloc_state = SPU_FREE
					spu = spu_get_idle(ctx)
					    - searches for a SPE in
					      state SPU_FREE, gets
					      the context just
					      freed by thread 1
					spu_schedule(ctx, spu)
					  spu->alloc_state = SPU_USED
spu_schedule(newctx, spu)
  - assumes spu is still free
  - tries to schedule context on
    already-used spu

This change introduces a 'free_spu' flag to spu_unschedule, to indicate
whether or not the function should free the spu after descheduling the
context. We only set this flag if we're not going to re-schedule
another context on this SPU.

Add a comment to document this behaviour.
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>

Commit 8d5636fb introduced a reference
count on SPU contexts during find_victim, but this may cause a leak in
the reference count if we later find a better contender for a context to
unschedule.

Change the reference to after we've found our victim context, so we
don't do the extra get_spu_context().
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>

Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>

Based on an original patch from Christoph Hellwig <hch@lst.de>.

Currently, there is a possible reference-after-free in the spusched
code - contexts may be freed after we have released their state_mutex
in spusched_tick and find_victim.

This change takes a reference to the context before releasing the
mutex, so that the context doesn't get destroyed.
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>

Currently, spu_run ignores the npc argument for contexts created with
SPU_CREATE_NOSCHED. While this is correct for isolated contexts,
there's no need to enforce the npc restriction on non-isolated NOSCHED
contexts.

This means that NOSCHED contexts can only ever run with an entry point
of 0x0.

This change to spu_run_init allows setting of the npc (and, while we're
at it, the privcntl) for non-isolated NOSCHED contexts. This allows
us to run NOSCHED contexts from any entry point.
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>

Kmem cache passed to constructor is only needed for constructors that are
themselves multiplexeres.  Nobody uses this "feature", nor does anybody uses
passed kmem cache in non-trivial way, so pass only pointer to object.

Non-trivial places are:
	arch/powerpc/mm/init_64.c
	arch/powerpc/mm/hugetlbpage.c

This is flag day, yes.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Acked-by: NPekka Enberg <penberg@cs.helsinki.fi>
Acked-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Jon Tollefson <kniht@linux.vnet.ibm.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Matt Mackall <mpm@selenic.com>
[akpm@linux-foundation.org: fix arch/powerpc/mm/hugetlbpage.c]
[akpm@linux-foundation.org: fix mm/slab.c]
[akpm@linux-foundation.org: fix ubifs]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This uses the new vm_ops->access to allow gdb to access the SPU local
store.  We currently prevent access to problem state registers, this can
be done later if really needed but it's safer not to.

[akpm@linux-foundation.org: fix typo]
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NRik van Riel <riel@redhat.com>
Cc: Dave Airlie <airlied@linux.ie>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch adjusts the placement of a reference context from
a spu affinity chain. The reference context can now be placed
only on nodes that have enough spus not intended to be used by
another gang (already running on the node).
Signed-off-by: NAndre Detsch <adetsch@br.ibm.com>
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>

Currenlt,, it is possible to lock aff_mutex and
cbe_spu_info[n].list_mutex in different orders, allowing a deadlock to
occur. With this change, aff_mutex is not taken within a list_mutex
critical section anymore.
Signed-off-by: NAndre Detsch <adetsch@br.ibm.com>
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>

kcalloc is supposed to be called with the count as its first argument and
the element size as the second.
Signed-off-by: NMilton Miller <miltonm@bga.com>
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>

As nr_active counter includes also spus waiting for syscalls to return
we need a seperate counter that only counts spus that are currently running
on spu side. This counter shall be used by a cpufreq governor that targets
a frequency dependent from the number of running spus.
Signed-off-by: NChristian Krafft <krafft@de.ibm.com>
Acked-by: NJeremy Kerr <jk@ozlabs.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Currently, the .ctx debug file in spu context directories is always
present.

We'd prefer to prevent users from relying on this file, so add a
"debug" mount option to spufs. The .ctx file will only be added to
the context directories when this option is present.
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>

Populate the size member of a few context files. Leave out files that
have different semantics with read vs mmap, or contain a
variable-length hex string.
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>

Currently, spufs never specifies the i_size for the files in context
directories, so stat() always reports 0-byte files.

This change adds allows the spufs_dir_(nosched_)contents arrays to
specify a file size. This allows stat() to report correct file sizes,
and makes SEEK_END work.
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>

Use a set of #defines for the size of context mappings, instead of
magic numbers.
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>

An spu context shouldn't get an extra tick if the time slice code
couldn't find something else to run. This means contexts that are not
within spu_run (ie, SPU_SCHED_SPU_RUN is cleared) will not receive
extra ticks while we have no other contexts waiting.
Signed-off-by: NLuke Browning <lukebrowning@us.ibm.com>
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>

Add a ctxt file to spufs that shows spu context information that is used
in scheduling. This info can be used for debugging spufs scheduler
issues, and to isolate between application and spufs problems as it
shows a lot of state such as priorities and dispatch counts.

This file contains internal spufs state and is subject to change at any
time, and therefore no applications should depend on it.  The file is
intended for the use of spufs kernel developers.
Signed-off-by: NLuke Browning <lukebrowning@us.ibm.com>
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>

Signed-off-by: NNick Piggin <npiggin@suse.de>
Acked-by: NJeremy Kerr <jk@ozlabs.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

There is a delay in the transition to the stopped state for class 2
interrupts. In some cases, the controlling thread detects the state of
the spu as running, and goes back to sleep resulting in a hung
application as the event is missed.

This change detects the stop condition and re-generates the wakeup event
after a context save.
Signed-off-by: NLuke Browning <lukebrowning@us.ibm.com>
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>

Time slicing can occur at the same time as spu exception handling
resulting in the wakeup of the wrong thread.

This change uses the the spu's register_lock to enforce synchronization
between bind/unbind and spu exception handling so that they are
mutually exclusive.
Signed-off-by: NLuke Browning <lukebrowning@us.ibm.com>
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>

According to the CBEA, the SPU dsisr is not updated for class 0
exceptions.

spu_stopped() is testing the dsisr that was passed to it from the class
0 exception handler, so we return a false positive here.

This patch cleans up the interrupt handler and erroneous tests in
spu_stopped. It also removes the fields from the csa since it is not
needed to process class 0 events.
Signed-off-by: NLuke Browning <lukebrowning@us.ibm.com>
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>

If the spu is stopping (ie, the SPU_STATUS_RUNNING bit is still set),
re-read the register to get the final stopped value.
Signed-off-by: NLuke Browning <lukebrowning@us.ibm.com>
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>

With CONFIG_VIRT_CPU_ACCOUNTING disabled, I got the following error:

linux-2.6/arch/powerpc/platforms/cell/spufs/file.c: In function 'spu_switch_log_notify':
linux-2.6/arch/powerpc/platforms/cell/spufs/file.c:2542: error: implicit declaration of function 'get_tb'
make[4]: *** [arch/powerpc/platforms/cell/spufs/file.o] Error 1
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

If victim (not ctx) is in spu_run, add victim to rq.
Signed-off-by: NLuke Browning <lukebrowning@us.ibm.com>
Acked-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

We need to acquire the parent i_mutex with I_MUTEX_PARENT to keep
lockdep happy.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>

We should not requeue the victim context in find_victim if the owner is
not in spu_run. It's first not needed because leaving the context on
the spu is an optimization and second is harmful because it means the
owner could re-enter spu_run when the context is on the runqueue and
trip the BUG_ON in __spu_update_sched_info.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>

Creating a spufs context or gand using spu_create should send an inotify
event so that things like performance monitors have an easy way to find
out about newly created contexts.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>

Currently, page fault handlers don't issue a mfc restart if the context
switch pending flag is set, which can leave us with a hanging DMA after
a context restore.

This patch introduces fault pending flag that is set by the fault
handler and read by the context switch code, so that the latter can add
the restart bit at the right spot, after it has successfuly saved the
state of the mfc control register.
Signed-off-by: NLuke Browning <lukebr@linux.vnet.ibm.com>
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>