Re: [RFC PATCH 5/5] mm, slub: make reclaim_account attribute read-only

Kees Cook
2020-06-05T21:07:31Z

On Tue, Jun 02, 2020 at 04:15:19PM +0200, Vlastimil Babka wrote:
> The attribute reflects the SLAB_RECLAIM_ACCOUNT cache flag. It's not clear why
> this attribute was writable in the first place, as it's tied to how the cache
> is used by its creator, it's not a user tunable. Furthermore:
>
> - it affects slab merging, but that's not being checked while toggled
> - if affects whether __GFP_RECLAIMABLE flag is used to allocate page, but
> the runtime toggle doesn't update allocflags
> - it affects cache_vmstat_idx() so runtime toggle might lead to incosistency
> of NR_SLAB_RECLAIMABLE and NR_SLAB_UNRECLAIMABLE
>
> Thus make it read-only.
>
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

Reviewed-by: Kees Cook <keescook@chromium.org>

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Kees Cook