Re: Page allocation failure on v3.8-rc5

Andrew Morton
2013-01-31T23:43:36Z

On Wed, 30 Jan 2013 19:53:22 +0800
Ming Lei <ming.lei@canonical.com> wrote:

> The allocation failure is caused by the big sizeof(struct parsed_partitions),
> which is 64K in my 32bit box,

Geeze.

We could fix that nicely by making parsed_partitions.parts an array of
pointers to a single `struct parsed_partition' and allocating those
on-demand.

But given the short-lived nature of this storage and the infrequency of
check_partition(), that isn't necessary.

> could you test the blow patch to see
> if it can fix the allocation failure?

(The patch is wordwrapped)

> ...
>
> @@ -106,18 +107,43 @@ static int (*check_part[])(struct parsed_partitions *) = {
> NULL
> };
>
> +struct parsed_partitions *allocate_partitions(int nr)
> +{
> + struct parsed_partitions *state;
> +
> + state = kzalloc(sizeof(struct parsed_partitions), GFP_KERNEL);

I personally prefer sizefo(*state) here. It means the reader doesn't
have to scroll back to check things.

> + if (!state)
> + return NULL;
> +
> + state->parts = vzalloc(nr * sizeof(state->parts[0]));
> + if (!state->parts) {
> + kfree(state);
> + return NULL;
> + }

It doesn't really need to be this complex - we could just vmalloc the
entire `struct parsed_partitions'. But I see that your change will
cause us to allcoate much less memory in many situations, which is
good. It should be mentioned in the changelog!