Eric Dumazet <[EMAIL PROTECTED]> wrote:
> If space considerations are that important, we could then reserve one bit
> for the 'wait_lock spinlock'
That makes life quite a bit more tricky, though it does have the advantage
that it closes the reader-jumping-writer window I mentioned.
> Another
On Fri, 13 Apr 2007 14:31:52 +0100
David Howells <[EMAIL PROTECTED]> wrote:
> Break the counter down like this:
>
> 0x - not locked; queue empty
> 0x4000 - locked by writer; queue empty
> 0xc000 - locket by writer; queue occupied
>
On Fri, Apr 13, 2007 at 02:31:52PM +0100, David Howells wrote:
> Nick Piggin <[EMAIL PROTECTED]> wrote:
>
> > The other way happens to be better for everyone else, which is why I
> > think your suggestion to instead move everyone to the spinlock version
> > was weird.
>
> No, you misunderstand
Nick Piggin <[EMAIL PROTECTED]> wrote:
> The other way happens to be better for everyone else, which is why I
> think your suggestion to instead move everyone to the spinlock version
> was weird.
No, you misunderstand me. My preferred solution is to leave it up to the arch
and not to make it
On Fri, Apr 13, 2007 at 02:43:03PM +0200, Nick Piggin wrote:
> Yes, this is the case on our 2 premiere SMP powerhouse architectures,
> sparc32 and parsic.
sparc32 is ultra-legacy and I have a tremendous amount of work to do on
SMP there. I don't feel that efficiency of locking primitives is a
David, you keep saying the same things and don't listen to me.
On Fri, Apr 13, 2007 at 01:09:42PM +0100, David Howells wrote:
> Nick Piggin <[EMAIL PROTECTED]> wrote:
>
> > This patch converts all architectures to a generic rwsem implementation,
> > which will compile down to the same code for
On Fri, Apr 13, 2007 at 12:44:50PM +0100, David Howells wrote:
> Nick Piggin <[EMAIL PROTECTED]> wrote:
>
> > I think I should put wait_lock after wait_list, so as to get a better
> > packing on most 64-bit architectures.
>
> It makes no difference. struct lockdep_map contains at least one
Nick Piggin <[EMAIL PROTECTED]> wrote:
> This patch converts all architectures to a generic rwsem implementation,
> which will compile down to the same code for i386, or powerpc, for
> example,
> and will allow some (eg. x86-64) to move away from spinlock based rwsems.
Which are better on UP
Nick Piggin <[EMAIL PROTECTED]> wrote:
> I think I should put wait_lock after wait_list, so as to get a better
> packing on most 64-bit architectures.
It makes no difference. struct lockdep_map contains at least one pointer and
so is going to be 8-byte aligned (assuming it's there at all).
On Fri, Apr 13, 2007 at 12:53:49PM +0200, Andi Kleen wrote:
> On Friday 13 April 2007 12:04:16 Nick Piggin wrote:
> > OK, this patch is against 2.6.21-rc6 + Mathieu's atomic_long patches.
> >
> > Last time this came up I was asked to get some numbers, so here are
> > some in the changelog,
On Fri, Apr 13, 2007 at 11:19:30AM +0100, Christoph Hellwig wrote:
> On Fri, Apr 13, 2007 at 12:04:16PM +0200, Nick Piggin wrote:
> > Remove one level of indirection (kernel/rwsem.c -> lib/rwsem.c), and
> > give a bit of a cleanup (eg remove the fastcall junk) to make the
> > code a bit easier to
On Friday 13 April 2007 12:04:16 Nick Piggin wrote:
> OK, this patch is against 2.6.21-rc6 + Mathieu's atomic_long patches.
>
> Last time this came up I was asked to get some numbers, so here are
> some in the changelog, captured with a simple kernel module tester.
> I got motivated again because
On Fri, Apr 13, 2007 at 12:04:16PM +0200, Nick Piggin wrote:
> OK, this patch is against 2.6.21-rc6 + Mathieu's atomic_long patches.
>
> Last time this came up I was asked to get some numbers, so here are
> some in the changelog, captured with a simple kernel module tester.
> I got motivated
On Fri, Apr 13, 2007 at 12:04:16PM +0200, Nick Piggin wrote:
> Remove one level of indirection (kernel/rwsem.c -> lib/rwsem.c), and
> give a bit of a cleanup (eg remove the fastcall junk) to make the
> code a bit easier to read.
Arpopos fastcalls, now that -mregparam=3 is the defaul on i386 and
On Fri, Apr 13, 2007 at 12:04:16PM +0200, Nick Piggin wrote:
Remove one level of indirection (kernel/rwsem.c - lib/rwsem.c), and
give a bit of a cleanup (eg remove the fastcall junk) to make the
code a bit easier to read.
Arpopos fastcalls, now that -mregparam=3 is the defaul on i386 and
On Fri, Apr 13, 2007 at 12:04:16PM +0200, Nick Piggin wrote:
OK, this patch is against 2.6.21-rc6 + Mathieu's atomic_long patches.
Last time this came up I was asked to get some numbers, so here are
some in the changelog, captured with a simple kernel module tester.
I got motivated again
On Friday 13 April 2007 12:04:16 Nick Piggin wrote:
OK, this patch is against 2.6.21-rc6 + Mathieu's atomic_long patches.
Last time this came up I was asked to get some numbers, so here are
some in the changelog, captured with a simple kernel module tester.
I got motivated again because of
On Fri, Apr 13, 2007 at 11:19:30AM +0100, Christoph Hellwig wrote:
On Fri, Apr 13, 2007 at 12:04:16PM +0200, Nick Piggin wrote:
Remove one level of indirection (kernel/rwsem.c - lib/rwsem.c), and
give a bit of a cleanup (eg remove the fastcall junk) to make the
code a bit easier to read.
On Fri, Apr 13, 2007 at 12:53:49PM +0200, Andi Kleen wrote:
On Friday 13 April 2007 12:04:16 Nick Piggin wrote:
OK, this patch is against 2.6.21-rc6 + Mathieu's atomic_long patches.
Last time this came up I was asked to get some numbers, so here are
some in the changelog, captured with a
Nick Piggin [EMAIL PROTECTED] wrote:
I think I should put wait_lock after wait_list, so as to get a better
packing on most 64-bit architectures.
It makes no difference. struct lockdep_map contains at least one pointer and
so is going to be 8-byte aligned (assuming it's there at all). struct
Nick Piggin [EMAIL PROTECTED] wrote:
This patch converts all architectures to a generic rwsem implementation,
which will compile down to the same code for i386, or powerpc, for
example,
and will allow some (eg. x86-64) to move away from spinlock based rwsems.
Which are better on UP kernels
On Fri, Apr 13, 2007 at 12:44:50PM +0100, David Howells wrote:
Nick Piggin [EMAIL PROTECTED] wrote:
I think I should put wait_lock after wait_list, so as to get a better
packing on most 64-bit architectures.
It makes no difference. struct lockdep_map contains at least one pointer and
David, you keep saying the same things and don't listen to me.
On Fri, Apr 13, 2007 at 01:09:42PM +0100, David Howells wrote:
Nick Piggin [EMAIL PROTECTED] wrote:
This patch converts all architectures to a generic rwsem implementation,
which will compile down to the same code for i386, or
On Fri, Apr 13, 2007 at 02:43:03PM +0200, Nick Piggin wrote:
Yes, this is the case on our 2 premiere SMP powerhouse architectures,
sparc32 and parsic.
sparc32 is ultra-legacy and I have a tremendous amount of work to do on
SMP there. I don't feel that efficiency of locking primitives is a
Nick Piggin [EMAIL PROTECTED] wrote:
The other way happens to be better for everyone else, which is why I
think your suggestion to instead move everyone to the spinlock version
was weird.
No, you misunderstand me. My preferred solution is to leave it up to the arch
and not to make it
On Fri, Apr 13, 2007 at 02:31:52PM +0100, David Howells wrote:
Nick Piggin [EMAIL PROTECTED] wrote:
The other way happens to be better for everyone else, which is why I
think your suggestion to instead move everyone to the spinlock version
was weird.
No, you misunderstand me. My
On Fri, 13 Apr 2007 14:31:52 +0100
David Howells [EMAIL PROTECTED] wrote:
Break the counter down like this:
0x - not locked; queue empty
0x4000 - locked by writer; queue empty
0xc000 - locket by writer; queue occupied
0x0nnn
Eric Dumazet [EMAIL PROTECTED] wrote:
If space considerations are that important, we could then reserve one bit
for the 'wait_lock spinlock'
That makes life quite a bit more tricky, though it does have the advantage
that it closes the reader-jumping-writer window I mentioned.
Another
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