diff options
| author | Jack Steiner <steiner@sgi.com> | 2009-12-15 16:48:17 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-12-16 07:20:16 -0800 |
| commit | 0cd2b0813aac660f5f7a6574083157a70c152dd5 (patch) | |
| tree | 906bf285391bf3d9ad72f9c94838fbb067453ec4 | |
| parent | 5658366ab55cccab24b4799b3ff8e94bdc1cc529 (diff) | |
| download | linux-0cd2b0813aac660f5f7a6574083157a70c152dd5.tar.bz2 | |
gru: fix bug in allocation of kernel contexts
Fix a bug in the assignment of GRU contexts used for kernel functions. If
a sleep occurs on the wait for a semaphore, the thread could switch cpus
and allocate resources on the wrong blade.
Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | drivers/misc/sgi-gru/grukservices.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/drivers/misc/sgi-gru/grukservices.c b/drivers/misc/sgi-gru/grukservices.c index c13342dda5fd..bfbf8fdbcd37 100644 --- a/drivers/misc/sgi-gru/grukservices.c +++ b/drivers/misc/sgi-gru/grukservices.c @@ -221,13 +221,21 @@ static int gru_free_kernel_contexts(void) static struct gru_blade_state *gru_lock_kernel_context(int blade_id) { struct gru_blade_state *bs; + int bid; STAT(lock_kernel_context); - bs = gru_base[blade_id]; +again: + bid = blade_id < 0 ? uv_numa_blade_id() : blade_id; + bs = gru_base[bid]; + /* Handle the case where migration occured while waiting for the sema */ down_read(&bs->bs_kgts_sema); + if (blade_id < 0 && bid != uv_numa_blade_id()) { + up_read(&bs->bs_kgts_sema); + goto again; + } if (!bs->bs_kgts || !bs->bs_kgts->ts_gru) - gru_load_kernel_context(bs, blade_id); + gru_load_kernel_context(bs, bid); return bs; } @@ -256,7 +264,7 @@ static int gru_get_cpu_resources(int dsr_bytes, void **cb, void **dsr) BUG_ON(dsr_bytes > GRU_NUM_KERNEL_DSR_BYTES); preempt_disable(); - bs = gru_lock_kernel_context(uv_numa_blade_id()); + bs = gru_lock_kernel_context(-1); lcpu = uv_blade_processor_id(); *cb = bs->kernel_cb + lcpu * GRU_HANDLE_STRIDE; *dsr = bs->kernel_dsr + lcpu * GRU_NUM_KERNEL_DSR_BYTES; |