Kirill,
>
> 12.02.2014, 16:15, "Allen Pais" <allen.pais@xxxxxxxxxx>:
>> On Wednesday 12 February 2014 05:13 PM, Kirill Tkhai wrote:
>>
>>> 12.02.2014, 15:29, "Allen Pais" <allen.pais@xxxxxxxxxx>:
>>>>>>>> [ 1487.027884] I7: <rt_mutex_setprio+0x3c/0x2c0>
>>>>>>>> [ 1487.027885] Call Trace:
>>>>>>>> [ 1487.027887] [00000000004967dc] rt_mutex_setprio+0x3c/0x2c0
>>>>>>>> [ 1487.027892] [00000000004afe20] task_blocks_on_rt_mutex+0x180/0x200
>>>>>>>> [ 1487.027895] [0000000000819114] rt_spin_lock_slowlock+0x94/0x300
>>>>>>>> [ 1487.027897] [0000000000817ebc] __schedule+0x39c/0x53c
>>>>>>>> [ 1487.027899] [00000000008185fc] schedule+0x1c/0xc0
>>>>>>>> [ 1487.027908] [000000000048fff4] smpboot_thread_fn+0x154/0x2e0
>>>>>>>> [ 1487.027913] [000000000048753c] kthread+0x7c/0xa0
>>>>>>>> [ 1487.027920] [00000000004060c4] ret_from_syscall+0x1c/0x2c
>>>>>>>> [ 1487.027922] [0000000000000000] (null)
>>
>> I am not convinced that I've covered all tlb/smp code. Guess I'll need to dig more.
>
> ++all above. May we have to add one more crutch... Put preempt_disable() at begining of
> __set_pte_at() and enable at end...
I realized locking in tsb is very tricky. My attempts to try and get hackbench run
without causing a stall failed. So here's what I tried to fix it, am not sure if it's
an appropriate fix, I would love to get comments. I have tested this fix for over 24 hours
with hackbench and dd, the system did not stall :)
diff --git a/arch/sparc/mm/tsb.c b/arch/sparc/mm/tsb.c
index 9eb10b4..24dcd29 100644
--- a/arch/sparc/mm/tsb.c
+++ b/arch/sparc/mm/tsb.c
@@ -6,6 +6,7 @@
#include <linux/kernel.h>
#include <linux/preempt.h>
#include <linux/slab.h>
+#include <linux/locallock.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/mmu_context.h>
@@ -14,6 +15,7 @@
#include <asm/oplib.h>
extern struct tsb swapper_tsb[KERNEL_TSB_NENTRIES];
+static DEFINE_LOCAL_IRQ_LOCK(tsb_lock);
static inline unsigned long tsb_hash(unsigned long vaddr, unsigned long hash_sh
{
@@ -71,9 +73,9 @@ static void __flush_tsb_one(struct tlb_batch *tb, unsigned lon
void flush_tsb_user(struct tlb_batch *tb)
{
struct mm_struct *mm = tb->mm;
- unsigned long nentries, base, flags;
+ unsigned long nentries, base;
- raw_spin_lock_irqsave(&mm->context.lock, flags);
+ local_lock(tsb_lock);
base = (unsigned long) mm->context.tsb_block[MM_TSB_BASE].tsb;
nentries = mm->context.tsb_block[MM_TSB_BASE].tsb_nentries;
@@ -90,7 +92,7 @@ void flush_tsb_user(struct tlb_batch *tb)
__flush_tsb_one(tb, HPAGE_SHIFT, base, nentries);
}
#endif
- raw_spin_unlock_irqrestore(&mm->context.lock, flags);
+ local_unlock(tsb_lock);
}
Thanks,
- Allen
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