Re: [RFC][WIP][PATCH] Add IRQSTACKS to ppc32
On Thu, Apr 24, 2008 at 12:37:50AM -0500, Kumar Gala wrote: config IRQSTACKS bool Use separate kernel stacks when processing interrupts - depends on PPC64 Why do we have this as a user-selectable option? It should be on by default on 32 or 64bit. ___ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
Re: [RFC][WIP][PATCH] Add IRQSTACKS to ppc32
On Fri, 2008-04-25 at 09:23 +0200, Christoph Hellwig wrote: On Thu, Apr 24, 2008 at 12:37:50AM -0500, Kumar Gala wrote: config IRQSTACKS bool Use separate kernel stacks when processing interrupts - depends on PPC64 Why do we have this as a user-selectable option? It should be on by default on 32 or 64bit. History maybe ? In the early days it was a bit experimental (we had a couple of issues that popped up with some thread flags not being properly recovered etc...). Nowadays, I agree it should not be an option. Ben. ___ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
Re: [RFC][WIP][PATCH] Add IRQSTACKS to ppc32
On Apr 25, 2008, at 8:03 AM, Benjamin Herrenschmidt wrote: On Fri, 2008-04-25 at 09:23 +0200, Christoph Hellwig wrote: On Thu, Apr 24, 2008 at 12:37:50AM -0500, Kumar Gala wrote: config IRQSTACKS bool Use separate kernel stacks when processing interrupts - depends on PPC64 Why do we have this as a user-selectable option? It should be on by default on 32 or 64bit. History maybe ? In the early days it was a bit experimental (we had a couple of issues that popped up with some thread flags not being properly recovered etc...). Nowadays, I agree it should not be an option. for some reason I felt that it was pretty much required on ppc64 when I did the port over to ppc32. Do we think we want to poke Paul to get this in for v2.6.26 so we can get it some more testing on all the ppc32 systems? - k ___ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
Re: [RFC][WIP][PATCH] Add IRQSTACKS to ppc32
Kumar Gala writes: Do we think we want to poke Paul to get this in for v2.6.26 so we can get it some more testing on all the ppc32 systems? It's not going in 2.6.26, since it's a pretty substantial change and it was first seen half-way through the merge window... Paul. ___ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
Re: [RFC][WIP][PATCH] Add IRQSTACKS to ppc32
On Thu, 2008-04-24 at 00:37 -0500, Kumar Gala wrote:
+ /*
+* interrupt stacks must be under 256MB, we cannot afford to
take
+* SLB misses on them.
+*/
+ for_each_possible_cpu(i) {
+ softirq_ctx[i] = (struct thread_info *)
+ __va(lmb_alloc_base(THREAD_SIZE,
+ THREAD_SIZE, 0x1000));
+ hardirq_ctx[i] = (struct thread_info *)
+ __va(lmb_alloc_base(THREAD_SIZE,
+ THREAD_SIZE, 0x1000));
+ }
+
The comment is a bit bogus :-) (about SLB misses). lowmem is your limit
I think. Also, why not share the code with ppc64 ?
Ben.
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Re: [RFC][WIP][PATCH] Add IRQSTACKS to ppc32
On Apr 24, 2008, at 2:18 AM, Benjamin Herrenschmidt wrote:
On Thu, 2008-04-24 at 00:37 -0500, Kumar Gala wrote:
+ /*
+* interrupt stacks must be under 256MB, we cannot afford to
take
+* SLB misses on them.
+*/
+ for_each_possible_cpu(i) {
+ softirq_ctx[i] = (struct thread_info *)
+ __va(lmb_alloc_base(THREAD_SIZE,
+ THREAD_SIZE,
0x1000));
+ hardirq_ctx[i] = (struct thread_info *)
+ __va(lmb_alloc_base(THREAD_SIZE,
+ THREAD_SIZE,
0x1000));
+ }
+
The comment is a bit bogus :-) (about SLB misses). lowmem is your
limit
I think. Also, why not share the code with ppc64 ?
I'm going to change it to be just lmb_alloc() so it will be difficult
to share with ppc64 (other than w/an ifdef).
- k
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Re: [RFC][WIP][PATCH] Add IRQSTACKS to ppc32
On Thu, 2008-04-24 at 07:59 -0500, Kumar Gala wrote: I'm going to change it to be just lmb_alloc() so it will be difficult to share with ppc64 (other than w/an ifdef). Unless we change lmb_alloc to just be an lmb_alloc_base with 0 and have the later do the right thing ? You don't put highmem in the LMBs ? If you do, we do need to have the max lowmem there no ? Ben. ___ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
Re: [RFC][WIP][PATCH] Add IRQSTACKS to ppc32
On Apr 24, 2008, at 9:53 AM, Benjamin Herrenschmidt wrote: On Thu, 2008-04-24 at 07:59 -0500, Kumar Gala wrote: I'm going to change it to be just lmb_alloc() so it will be difficult to share with ppc64 (other than w/an ifdef). Unless we change lmb_alloc to just be an lmb_alloc_base with 0 and have the later do the right thing ? don't follow. Look at the real patch and comment on that. You don't put highmem in the LMBs ? If you do, we do need to have the max lowmem there no ? we restrict lmb alloc via LMB_REAL_LIMIT in include/asm-powerpc/lmb.h - k ___ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
