Changeset 434f700 in mainline for src/mm/tlb.c

Timestamp:

2005-04-26T16:17:41Z (20 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

babcb148

Parents:

dba84ff

Message:

Replace the deadlock-prone TLB shootdown algorithm with a deadlock-free implementation.
The implementation is a variant of the CMU TLB consistency algorithm.
Very inefficient implementation of a very inefficient (but correct) algorithm.

File:

• src/mm/tlb.c (modified) (4 diffs)

src/mm/tlb.c

@@ -34 +34 @@
 #include <arch/interrupt.h>
 #include <config.h>
+#include <arch.h>
 
 #ifdef __SMP__
 static spinlock_t tlblock;
-static volatile int tlb_shootdown_cnt;
 
 void tlb_init(void)
 {
         spinlock_initialize(&tlblock);
-        tlb_shootdown_cnt = 0;
 }
 
@@ -48 +47 @@
 void tlb_shootdown_start(void)
 {
+        int i;
+
+        CPU->tlb_active = 0;
         spinlock_lock(&tlblock);
         tlb_shootdown_ipi_send();
+        tlb_invalidate(0); /* TODO: use valid ASID */
         
-        while (tlb_shootdown_cnt < config.cpu_active - 1)
-                ;
-                
-        tlb_shootdown_cnt = 0;
+busy_wait:      
+        for (i = 0; i<config.cpu_active; i++)
+                if (cpus[i].tlb_active)
+                        goto busy_wait;
 }
 
@@ -60 +63 @@
 {
         spinlock_unlock(&tlblock);
+        CPU->tlb_active = 1;
 }
 
@@ -69 +73 @@
 void tlb_shootdown_ipi_recv(void)
 {
-        atomic_inc((int *) &tlb_shootdown_cnt);
+        CPU->tlb_active = 0;
         spinlock_lock(&tlblock);
         spinlock_unlock(&tlblock);
         tlb_invalidate(0);      /* TODO: use valid ASID */
+        CPU->tlb_active = 1;
 }
 #endif /* __SMP__ */