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authorRusty Russell <rusty@rustcorp.com.au>2009-07-30 16:03:45 -0600
committerRusty Russell <rusty@rustcorp.com.au>2009-07-30 16:03:46 +0930
commita91d74a3c4de8115295ee87350c13a329164aaaf (patch)
tree02c862fccc9abedf7fc354061e69c4b5fbcce06d /drivers/lguest/hypercalls.c
parent2e04ef76916d1e29a077ea9d0f2003c8fd86724d (diff)
lguest: update commentry
Every so often, after code shuffles, I need to go through and unbitrot the Lguest Journey (see drivers/lguest/README). Since we now use RCU in a simple form in one place I took the opportunity to expand that explanation. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Ingo Molnar <mingo@redhat.com> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'drivers/lguest/hypercalls.c')
-rw-r--r--drivers/lguest/hypercalls.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/drivers/lguest/hypercalls.c b/drivers/lguest/hypercalls.c
index 787ab4bc09f..83511eb0923 100644
--- a/drivers/lguest/hypercalls.c
+++ b/drivers/lguest/hypercalls.c
@@ -59,7 +59,7 @@ static void do_hcall(struct lg_cpu *cpu, struct hcall_args *args)
case LHCALL_SHUTDOWN: {
char msg[128];
/*
- * Shutdown is such a trivial hypercall that we do it in four
+ * Shutdown is such a trivial hypercall that we do it in five
* lines right here.
*
* If the lgread fails, it will call kill_guest() itself; the
@@ -245,6 +245,10 @@ static void initialize(struct lg_cpu *cpu)
* device), the Guest will still see the old page. In practice, this never
* happens: why would the Guest read a page which it has never written to? But
* a similar scenario might one day bite us, so it's worth mentioning.
+ *
+ * Note that if we used a shared anonymous mapping in the Launcher instead of
+ * mapping /dev/zero private, we wouldn't worry about cop-on-write. And we
+ * need that to switch the Launcher to processes (away from threads) anyway.
:*/
/*H:100