On Wed, Apr 05, 2006 at 03:02:46PM -0700, Daniel Phillips wrote:
> > page = alloc_page(GFP_ATOMIC);
>
> A slightly different objection than Andrew's: this will rapidly eat up
> all the pages available for, e.g., receiving network packets, probably
> not what you want. How about flags=0? This will dip a little way into
> reserves but not as far as interrupts or realtime tasks, and will not
> attempt any reclaim. (Maybe we should have a GFP define for that.)
Yeah, it's a bit non-obvious what 0 means in the twisty little maze of
GFP_ flags.
However, I do want to push the system into reclaim later. It looks
like the only difference between 0 and GFP_ATOMIC is the use of
emergency pools, which I don't really want to exercise anyway.
> > INIT_LIST_HEAD(&unplugged->list);
> > list_add(&unplugged->list, &unplugged_pages);
>
> You don't need to initialize the list element you are adding.
This look OK to you?
Index: linux-2.6.16/arch/um/drivers/mconsole_kern.c
===================================================================
--- linux-2.6.16.orig/arch/um/drivers/mconsole_kern.c 2006-04-03
18:05:29.000000000 -0400
+++ linux-2.6.16/arch/um/drivers/mconsole_kern.c 2006-04-05
22:54:17.000000000 -0400
@@ -87,7 +87,11 @@ static irqreturn_t mconsole_interrupt(in
if(req.cmd->context == MCONSOLE_INTR)
(*req.cmd->handler)(&req);
else {
- new = kmalloc(sizeof(*new), GFP_ATOMIC);
+ /* 0 means don't wait (like GFP_ATOMIC) and
+ * don't dip into emergency pools (unlike
+ * GFP_ATOMIC).
+ */
+ new = kmalloc(sizeof(*new), 0);
if(new == NULL)
mconsole_reply(&req, "Out of memory", 1, 0);
else {
@@ -415,7 +419,6 @@ static int mem_config(char *str)
unplugged = page_address(page);
if(unplug_index == UNPLUGGED_PER_PAGE){
- INIT_LIST_HEAD(&unplugged->list);
list_add(&unplugged->list, &unplugged_pages);
unplug_index = 0;
}
@@ -655,7 +658,6 @@ static void with_console(struct mc_reque
struct mconsole_entry entry;
unsigned long flags;
- INIT_LIST_HEAD(&entry.list);
entry.request = *req;
list_add(&entry.list, &clients);
spin_lock_irqsave(&console_lock, flags);
Jeff
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