# Re: \[PATCH 2/4\] mm: speed up mremap by 500x on large regions (v2)

- From: Christoph Hellwig \<hch@infradead.org\>
- Date: 2018-10-15 09:42:29 
- List: linuxppc-dev
- Page: https://ratatoskr.run/linuxppc-dev/2018/10/6489769
- Thread: https://ratatoskr.run/linux-mm/2018/10/6489750/t.md

```text
On Fri, Oct 12, 2018 at 06:31:58PM -0700, Joel Fernandes (Google) wrote:
> Android needs to mremap large regions of memory during memory management
> related operations.

Just curious: why?

> +	if ((old_addr & ~PMD_MASK) || (new_addr & ~PMD_MASK)
> +	    || old_end - old_addr < PMD_SIZE)

The || goes on the first line.

> +		} else if (extent == PMD_SIZE && IS_ENABLED(CONFIG_HAVE_MOVE_PMD)) {

Overly long line.
```