[RFA] dcache invalidate fix

Michael Snyder
2009-11-10T21:35:13Z

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Doug, I'm vague about this, but it seems right and it fixes the
bug that I'm running into.

It seems like dcache_invalidate_line needs to remove the block
from the in use list at the same time as adding it to the freed
list.

The problem that bit me was getting the two lists cross-linked,
which eventually led to an infinite loop behavior in dcache_invalidate.

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2009-11-10 Michael Snyder <msnyder@vmware.com>

* dcache.c (dcache_invalidate_line): Remove block from used list
when adding it to freed list.

Index: dcache.c
===================================================================
RCS file: /cvs/src/src/gdb/dcache.c,v
retrieving revision 1.37
diff -u -p -r1.37 dcache.c
--- dcache.c 10 Nov 2009 18:36:50 -0000 1.37
+++ dcache.c 10 Nov 2009 21:31:03 -0000
@@ -167,10 +167,18 @@ dcache_invalidate_line (DCACHE *dcache,

if (db)
{
+ struct dcache_block *db2;
splay_tree_remove (dcache->tree, (splay_tree_key) db->addr);
db->newer = dcache->freelist;
dcache->freelist = db;
--dcache->size;
+ /* Remove db from dcache in-use chain. */
+ for (db2 = dcache->oldest; db2; db2 = db2->newer)
+ if (db2->newer == db)
+ {
+ dcache->newest = db2;
+ db2->newer = NULL;
+ }
}
}