On 08/10/2016 08:16 AM, js1304@xxxxxxxxx wrote:
From: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> What debug_pagealloc does is just mapping/unmapping page table. Basically, it doesn't need additional memory space to memorize something. But, with guard page feature, it requires additional memory to distinguish if the page is for guard or not. Guard page is only used when debug_guardpage_minorder is non-zero so this patch removes additional memory allocation (page_ext) if debug_guardpage_minorder is zero. It saves memory if we just use debug_pagealloc and not guard page.
We could also save cycles with a static key for _debug_guardpage_enabled :) But memory savings are likely more significant, so
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
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