On Tue 11-08-20 11:18:07, Uladzislau Rezki wrote: > On Mon, Aug 10, 2020 at 09:25:25PM +0200, Michal Hocko wrote: > > On Mon 10-08-20 18:07:39, Uladzislau Rezki wrote: > > > > On Sun 09-08-20 22:43:53, Uladzislau Rezki (Sony) wrote: [...] > > > As i described before, calling the __get_free_page(0) with 0 as argument > > > will solve the (a). How correctly is it? From my point of view the logic > > > that bypass the wakeup path should be explicitly defined. > > > > gfp_mask == 0 is GFP_NOWAIT (aka an atomic allocation request) which > > doesn't wake up kswapd. So if the wakeup is a problem then this would be > > a way to go. > > > What do you mean Michal? gfp_mask 0 != GFP_NOWAIT: > > #define GFP_NOWAIT (__GFP_KSWAPD_RECLAIM) > > it does wakeup of the kswapd. Or am i missing something? Please comment. > If we are about to avoid the kswapd, should we define something special? > > #define GFP_NOWWAKE_KSWAPD 0 Sorry, I was more cryptic than necessary. What I meant is that GFP_NOWAIT is the basic non-sleepable allocation. It does wake up kswapd but a lack of it can be expressed GFP_NOWAIT & ~__GFP_KSWAPD_RECLAIM which is 0, now. The mouthfull variant is better for future maintainability. -- Michal Hocko SUSE Labs
