Re: [PATCH] block: partition: optimize memory allocation incheck_partition

From: Joe Perches
Date: Thu Jan 31 2013 - 22:20:42 EST


On Fri, 2013-02-01 at 11:07 +0800, Ming Lei wrote:
> Currently, sizeof(struct parsed_partitions) may be 64KB in 32bit arch,
> so it is easy to trigger page allocation failure by check_partition,
[]
> This patch does below optimizations on the allocation of struct
> parsed_partitions to try to address the issue:
>
> - make parsed_partitions.parts as pointer so that the pointed memory
> can fit in 32KB buffer, then approximate 32KB memory can be saved
>
> - vmalloc the buffer pointed by parsed_partitions.parts because
> 32KB is still a bit big for kmalloc
[]
> diff --git a/block/partitions/check.h b/block/partitions/check.h
[]
> @@ -15,13 +15,15 @@ struct parsed_partitions {
> int flags;
> bool has_info;
> struct partition_meta_info info;
> - } parts[DISK_MAX_PARTS];
> + } *parts;

This is relatively unusual style.
Could you break out this struct instead?

struct partition_parts {
...
};

and use

struct partition_parts *parts;

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