linux-toradex.git/include/linux/padata.h, branch v5.1-rc1

padata: ensure padata_do_serial() runs on the correct CPU

2017-10-07T04:10:32+00:00

If the algorithm we're parallelizing is asynchronous we might change
CPUs between padata_do_parallel() and padata_do_serial(). However, we
don't expect this to happen as we need to enqueue the padata object into
the per-cpu reorder queue we took it from, i.e. the same-cpu's parallel
queue.

Ensure we're not switching CPUs for a given padata object by tracking
the CPU within the padata object. If the serial callback gets called on
the wrong CPU, defer invoking padata_reorder() via a kernel worker on
the CPU we're expected to run on.

Signed-off-by: Mathias Krause 
Signed-off-by: Herbert Xu

padata: ensure the reorder timer callback runs on the correct CPU

2017-10-07T04:10:31+00:00

The reorder timer function runs on the CPU where the timer interrupt was
handled which is not necessarily one of the CPUs of the 'pcpu' CPU mask
set.

Ensure the padata_reorder() callback runs on the correct CPU, which is
one in the 'pcpu' CPU mask set and, preferrably, the next expected one.
Do so by comparing the current CPU with the expected target CPU. If they
match, call padata_reorder() right away. If they differ, schedule a work
item on the target CPU that does the padata_reorder() call for us.

Signed-off-by: Mathias Krause 
Signed-off-by: Herbert Xu

padata: Make padata_alloc() static

2017-05-26T08:10:37+00:00

No users outside of padata.c

Signed-off-by: Thomas Gleixner 
Tested-by: Paul E. McKenney 
Acked-by: Ingo Molnar 
Cc: Steffen Klassert 
Cc: Peter Zijlstra 
Cc: Sebastian Siewior 
Cc: Steven Rostedt 
Cc: linux-crypto@vger.kernel.org
Link: http://lkml.kernel.org/r/20170524081547.491457256@linutronix.de

padata: Convert to hotplug state machine

2016-09-19T19:44:30+00:00

Install the callbacks via the state machine. CPU-hotplug multinstance support
is used with the nocalls() version. Maybe parts of padata_alloc() could be
moved into the online callback so that we could invoke ->startup callback for
instance and drop get_online_cpus().

Signed-off-by: Sebastian Andrzej Siewior 
Cc: Steffen Klassert 
Cc: Peter Zijlstra 
Cc: linux-crypto@vger.kernel.org
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160906170457.32393-14-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner

kernel/padata.c: removed unused code

2016-05-20T02:12:14+00:00

By accident I stumbled across code that has never been used.  This
driver has EXPORT_SYMBOL functions, and the only user of the code is
pcrypt.c, but this only uses a subset of the exported symbols.

According to 'git log -G', the functions, padata_set_cpumasks,
padata_add_cpu, and padata_remove_cpu have never been used since they
were first introduced.  This patch removes the unused code.

On one 64 bit build, with CRYPTO_PCRYPT built in, the text is more than
4k smaller.

  kbuild_hp> size $KBUILD_OUTPUT/vmlinux
      text    data     bss      dec hex    filename
  10566658 4678360 1122304 16367322 f9beda vmlinux
  10561984 4678360 1122304 16362648 f9ac98 vmlinux

On another config, 32 bit, the saving is about 0.5k bytes.

  kbuild_hp-x86> size $KBUILD_OUTPUT/vmlinux
  6012005 2409513 2785280 11206798 ab008e vmlinux
  6011491 2409513 2785280 11206284 aafe8c vmlinux

Signed-off-by: Richard Cochran 
Cc: Steffen Klassert 
Cc: Herbert Xu 
Cc: "David S. Miller" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

padata: make the sequence counter an atomic_t

2013-10-30T04:02:58+00:00

Using a spinlock to atomically increase a counter sounds wrong -- we've
atomic_t for this!

Also move 'seq_nr' to a different cache line than 'lock' to reduce cache
line trashing. This has the nice side effect of decreasing the size of
struct parallel_data from 192 to 128 bytes for a x86-64 build, e.g.
occupying only two instead of three cache lines.

Those changes results in a 5% performance increase on an IPsec test run
using pcrypt.

Btw. the seq_lock spinlock was never explicitly initialized -- one more
reason to get rid of it.

Signed-off-by: Mathias Krause 
Acked-by: Steffen Klassert 
Signed-off-by: Herbert Xu

padata: Fix race on sequence number wrap

2012-03-14T09:25:56+00:00

When padata_do_parallel() is called from multiple cpus for the same
padata instance, we can get object reordering on sequence number wrap
because testing for sequence number wrap and reseting the sequence
number must happen atomically but is implemented with two atomic
operations. This patch fixes this by converting the sequence number
from atomic_t to an unsigned int and protect the access with a
spin_lock. As a side effect, we get rid of the sequence number wrap
handling because the seqence number wraps back to null now without
the need to do anything.

Signed-off-by: Steffen Klassert 
Signed-off-by: Herbert Xu

padata: add missing __percpu markup in include/linux/padata.h

2010-09-03T11:09:46+00:00

parallel_data->queue is a percpu pointer but was missing __percpu markup.
Add it.

Signed-off-by: Namhyung Kim 
Acked-by: Steffen Klassert 
Signed-off-by: Herbert Xu

padata: Remove padata_get_cpumask

2010-07-31T11:53:06+00:00

A function that copies the padata cpumasks to a user buffer
is a bit error prone. The cpumask can change any time so we
can't be sure to have the right cpumask when using this function.
A user who is interested in the padata cpumasks should register
to the padata cpumask notifier chain instead. Users of
padata_get_cpumask are already updated, so we can remove it.

Signed-off-by: Steffen Klassert 
Signed-off-by: Herbert Xu

padata: Pass the padata cpumasks to the cpumask_change_notifier chain

2010-07-31T11:53:05+00:00

We pass a pointer to the new padata cpumasks to the cpumask_change_notifier
chain. So users can access the cpumasks without the need of an extra
padata_get_cpumask function.

Signed-off-by: Steffen Klassert 
Signed-off-by: Herbert Xu