Re: [PATCH v4, part3 11/15] mm: use a dedicated lock to protect totalram_pagesand zone->managed_pages

[Rik van Riel]

On 04/06/2013 09:55 AM, Jiang Liu wrote:

> @@ -5186,6 +5189,22 @@ early_param("movablecore", cmdline_parse_movablecore);
>
>   #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
>
> +void adjust_managed_page_count(struct page *page, long count)
> +{
> +	bool lock = (system_state != SYSTEM_BOOTING);
> +
> +	/* No need to acquire the lock during boot */
> +	if (lock)
> +		spin_lock(&managed_page_count_lock);
> +
> +	page_zone(page)->managed_pages += count;
> +	totalram_pages += count;
> +
> +	if (lock)
> +		spin_unlock(&managed_page_count_lock);
> +}

While I agree the boot code currently does not need the lock, is
there any harm to removing that conditional?

That would simplify the code, and protect against possible future
cleverness of initializing multiple memory things simultaneously.

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