Re: [PATCH] thp, mlock: update unevictable-lru.txt

[Dave Hansen <dave.hansen@intel.com>]

On 03/15/2016 07:55 AM, Kirill A. Shutemov wrote:
> +Transparent huge page is represented by single entry on a lru list and
> +therefore we can only make unevictable entire compound page, not
> +individual subpages.

A few grammar nits:

A transparent huge page is represented by a single entry on an lru list.
Therefore, we can only make unevictable an entire compound page, not
individual subpages.

...
> +We handle this by forbidding mlocking PTE-mapped huge pages. This way we
> +keep the huge page accessible for vmscan. Under memory pressure the page
> +will be split, subpages from VM_LOCKED VMAs moved to unevictable lru and
> +the rest can be evicted.

What do you mean by "mlocking" in this context?  Do you mean that we
actually return -ESOMETHING from mlock() on PTE-mapped huge pages?  Or,
do you just mean that we defer treating PTE-mapped huge pages as
PageUnevictable() inside the kernel?

I think we should probably avoid saying "mlocking" when we really mean
"kernel-internal mlocked page handling" aka. the unevictable list.

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>