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)
Ar Iau, 2006-06-22 am 21:29 +1000, ysgrifennodd Herbert Xu:
> Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
> >
> > The 8390 change (corrected version) also makes 8390.c faster so should
> > be applied anyway, and the orinoco one fixes some code that isn't even
> > needed and someone forgot to remove long ago. Otherwise the skb_padto
>
> Yeah I agree totally. However, I haven't actually seen the fixed 8390
> version being posted yet or at least not to netdev :)
Ah the resounding clang of a subtle hint ;)
Signed-off-by: Alan Cox <alan@redhat.com>
- Return 8390.c to the old way of handling short packets (which is also
faster)
- Remove the skb_padto from orinoco. This got left in when the padding bad
write patch was added and is actually not needed. This is fixing a merge
error way back when.
- Wavelan can also use the stack based buffer trick if you want
Signed-off-by: Jeff Garzik <jeff@garzik.org>
hi,
this is another array overrun spotted by coverity (#id 507)
we should check the index against array size before using it.
Not sure why the driver doesnt use ARRAY_SIZE instead of its
own macro.
Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Fix section mismatch warning:
WARNING: drivers/net/wireless/wavelan.o - Section mismatch: reference to
.init.text: from .text between 'init_module' (at offset 0x371e) and
'cleanup_module'
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Remove the "inline" keyword from a bunch of big functions in the kernel with
the goal of shrinking it by 30kb to 40kb
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Jeff Garzik <jgarzik@pobox.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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 Howells