Commit Graph

10 Commits

Author SHA1 Message Date
David Howells 7d12e780e0 IRQ: Maintain regs pointer globally rather than passing to IRQ handlers
Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
of passing regs around manually through all ~1800 interrupt handlers in the
Linux kernel.

The regs pointer is used in few places, but it potentially costs both stack
space and code to pass it around.  On the FRV arch, removing the regs parameter
from all the genirq function results in a 20% speed up of the IRQ exit path
(ie: from leaving timer_interrupt() to leaving do_IRQ()).

Where appropriate, an arch may override the generic storage facility and do
something different with the variable.  On FRV, for instance, the address is
maintained in GR28 at all times inside the kernel as part of general exception
handling.

Having looked over the code, it appears that the parameter may be handed down
through up to twenty or so layers of functions.  Consider a USB character
device attached to a USB hub, attached to a USB controller that posts its
interrupts through a cascaded auxiliary interrupt controller.  A character
device driver may want to pass regs to the sysrq handler through the input
layer which adds another few layers of parameter passing.

I've build this code with allyesconfig for x86_64 and i386.  I've runtested the
main part of the code on FRV and i386, though I can't test most of the drivers.
I've also done partial conversion for powerpc and MIPS - these at least compile
with minimal configurations.

This will affect all archs.  Mostly the changes should be relatively easy.
Take do_IRQ(), store the regs pointer at the beginning, saving the old one:

	struct pt_regs *old_regs = set_irq_regs(regs);

And put the old one back at the end:

	set_irq_regs(old_regs);

Don't pass regs through to generic_handle_irq() or __do_IRQ().

In timer_interrupt(), this sort of change will be necessary:

	-	update_process_times(user_mode(regs));
	-	profile_tick(CPU_PROFILING, regs);
	+	update_process_times(user_mode(get_irq_regs()));
	+	profile_tick(CPU_PROFILING);

I'd like to move update_process_times()'s use of get_irq_regs() into itself,
except that i386, alone of the archs, uses something other than user_mode().

Some notes on the interrupt handling in the drivers:

 (*) input_dev() is now gone entirely.  The regs pointer is no longer stored in
     the input_dev struct.

 (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking.  It does
     something different depending on whether it's been supplied with a regs
     pointer or not.

 (*) Various IRQ handler function pointers have been moved to type
     irq_handler_t.

Signed-Off-By: David Howells <dhowells@redhat.com>
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
2006-10-05 15:10:12 +01:00
Ingo Molnar 12aa757905 [ALSA] semaphore -> mutex (Archs, misc buses)
Semaphore to mutex conversion.

The conversion was generated via scripts, and the result was validated
automatically via a script as well.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2006-03-22 10:25:43 +01:00
Linus Torvalds 4da5cc2cec Merge git://git.kernel.org/pub/scm/linux/kernel/git/perex/alsa 2006-01-04 16:38:36 -08:00
Greg Kroah-Hartman 75318d2d7c [PATCH] USB: remove .owner field from struct usb_driver
It is no longer needed, so let's remove it, saving a bit of memory.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-04 13:48:34 -08:00
Takashi Iwai bbe85bbd02 [ALSA] Remove xxx_t typedefs: USB-USX2Y
Modules: USB USX2Y

Remove xxx_t typedefs from the USB-USX2Y driver.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
2006-01-03 12:19:56 +01:00
Takashi Iwai cb432379ef [ALSA] usx2y - Code clean up
Modules: USB USX2Y

Clean up snd-usb-usx2y driver code:

- Avoid unnecessary cast
- Fix spaces/indents
- Use kzalloc()
- Remove weird debug prints

Signed-off-by: Takashi Iwai <tiwai@suse.de>
2006-01-03 12:17:09 +01:00
Takashi Iwai d3d579f84e [ALSA] Add missing KERN_* prefix
Modules: ALSA<-OSS emulation,USB generic driver,USB USX2Y

Added missing KERN_* prefix to printk.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
2005-11-04 13:19:32 +01:00
Clemens Ladisch ee7333970b [ALSA] usb-audio - remove superfluous parameter
USB generic driver,USB USX2Y
This patch removes the superfluous driver parameter from the
disconnect functions.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
2005-05-29 10:05:14 +02:00
Karsten Wiese 230cd5e248 [ALSA] prevent oops & dead keyboard on usb unplugging while the device is being used
USB generic driver,USB USX2Y
Without this patch, some usb kobjects, which are parents to
the usx2y's kobjects can be freed before the usx2y's.
This led to an oops in get_kobj_path_length() and a dead
keyboard, when the usx2y's kobjects were freed.
The patch ensures the correct sequence.
Tested ok on kernel 2.6.12-rc2.

Signed-off-by: Karsten Wiese <annabellesgarden@yahoo.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2005-05-29 10:04:47 +02:00
Linus Torvalds 1da177e4c3 Linux-2.6.12-rc2
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!
2005-04-16 15:20:36 -07:00