Hi Sergey,
On Tue, Feb 06, 2018 at 06:48:22PM +0900, Sergey Senozhatsky wrote:
Hello,
On (02/06/18 01:02), Minchan Kim wrote: [..]
Can't we simple do like that if you want to make it simple and rely on someone who makes frontswap THP-aware later?
diff --git a/mm/swapfile.c b/mm/swapfile.c index 42fe5653814a..4bf1725407aa 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -934,7 +934,11 @@ int get_swap_pages(int n_goal, bool cluster, swp_entry_t swp_entries[]) /* Only single cluster request supported */ WARN_ON_ONCE(n_goal > 1 && cluster); +#ifdef CONFIG_FRONTSWAP
Wouldn't #ifdef CONFIG_THP_SWAP be better? frontswap_enabled() is 'false' on CONFIG_FRONTSWAP configs, should be compiled out anyway.
Agree.
/* Now, frontswap doesn't support THP page */if (frontswap_enabled() && cluster)return;+#endif avail_pgs = atomic_long_read(&nr_swap_pages) / nr_pages; if (avail_pgs <= 0) goto noswap;
Looks interesting. Technically, can be done earlier - in get_swap_page(), can't it? get_swap_page() has the PageTransHuge(page) && CONFIG_THP_SWAP condition checks. Can add frontswap dependency there. Something like
if (PageTransHuge(page)) { if (IS_ENABLED(CONFIG_THP_SWAP))
if (!frontswap_enabled()) get_swap_pages(1, true, &entry);
Looks better but it introduces frontswap thing to swap_slots.c while all frontswap works in swapfile.c.