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author | David S. Miller <davem@sunset.davemloft.net> | 2007-05-26 10:14:43 +0200 |
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committer | David S. Miller <davem@sunset.davemloft.net> | 2007-05-29 11:49:49 +0200 |
commit | 22adb358e816ce6aa0afb231ae9d826b0bddc8b0 (patch) | |
tree | 6f9886bf5b4e5c916c72d8d5733211813873c5fc /arch/sparc64/kernel/smp.c | |
parent | [SPARC64]: Use machine description and OBP properly for cpu probing. (diff) | |
download | linux-22adb358e816ce6aa0afb231ae9d826b0bddc8b0.tar.xz linux-22adb358e816ce6aa0afb231ae9d826b0bddc8b0.zip |
[SPARC64]: Eliminate NR_CPUS limitations.
Cheetah systems can have cpuids as large as 1023, although physical
systems don't have that many cpus.
Only three limitations existed in the kernel preventing arbitrary
NR_CPUS values:
1) dcache dirty cpu state stored in page->flags on
D-cache aliasing platforms. With some build time
calculations and some build-time BUG checks on
page->flags layout, this one was easily solved.
2) The cheetah XCALL delivery code could only handle
a cpumask with up to 32 cpus set. Some simple looping
logic clears that up too.
3) thread_info->cpu was a u8, easily changed to a u16.
There are a few spots in the kernel that still put NR_CPUS
sized arrays on the kernel stack, but that's not a sparc64
specific problem.
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'arch/sparc64/kernel/smp.c')
-rw-r--r-- | arch/sparc64/kernel/smp.c | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/arch/sparc64/kernel/smp.c b/arch/sparc64/kernel/smp.c index f7fa873c800d..c550bba3490a 100644 --- a/arch/sparc64/kernel/smp.c +++ b/arch/sparc64/kernel/smp.c @@ -400,7 +400,7 @@ static __inline__ void spitfire_xcall_deliver(u64 data0, u64 data1, u64 data2, c static void cheetah_xcall_deliver(u64 data0, u64 data1, u64 data2, cpumask_t mask) { u64 pstate, ver; - int nack_busy_id, is_jbus; + int nack_busy_id, is_jbus, need_more; if (cpus_empty(mask)) return; @@ -416,6 +416,7 @@ static void cheetah_xcall_deliver(u64 data0, u64 data1, u64 data2, cpumask_t mas __asm__ __volatile__("rdpr %%pstate, %0" : "=r" (pstate)); retry: + need_more = 0; __asm__ __volatile__("wrpr %0, %1, %%pstate\n\t" : : "r" (pstate), "i" (PSTATE_IE)); @@ -444,6 +445,10 @@ retry: : /* no outputs */ : "r" (target), "i" (ASI_INTR_W)); nack_busy_id++; + if (nack_busy_id == 32) { + need_more = 1; + break; + } } } @@ -460,6 +465,16 @@ retry: if (dispatch_stat == 0UL) { __asm__ __volatile__("wrpr %0, 0x0, %%pstate" : : "r" (pstate)); + if (unlikely(need_more)) { + int i, cnt = 0; + for_each_cpu_mask(i, mask) { + cpu_clear(i, mask); + cnt++; + if (cnt == 32) + break; + } + goto retry; + } return; } if (!--stuck) @@ -497,6 +512,8 @@ retry: if ((dispatch_stat & check_mask) == 0) cpu_clear(i, mask); this_busy_nack += 2; + if (this_busy_nack == 64) + break; } goto retry; |