On Tue 17-04-18 20:08:24, Matthew Wilcox wrote: > On Wed, Apr 18, 2018 at 11:29:12AM +0900, Minchan Kim wrote: > > If there are heavy memory pressure, page allocation with __GFP_NOWAIT > > fails easily although it's order-0 request. > > I got below warning 9 times for normal boot. > > > > [ 17.072747] c0 0 <snip >: page allocation failure: order:0, mode:0x2200000(GFP_NOWAIT|__GFP_NOTRACK) > > > > Let's not make user scared. > > > > - cw = kmalloc(sizeof(*cw), GFP_NOWAIT); > > + cw = kmalloc(sizeof(*cw), GFP_NOWAIT | __GFP_NOWARN); > > if (!cw) > > Not arguing against this patch. But how many places do we want to use > GFP_NOWAIT without __GFP_NOWARN? Not many, and the few which do do this > seem like they simply haven't added it yet. Maybe this would be a good idea? > > -#define GFP_NOWAIT (__GFP_KSWAPD_RECLAIM) > +#define GFP_NOWAIT (__GFP_KSWAPD_RECLAIM | __GFP_NOWARN) We have tried something like this in the past and Linus was strongly against. I do not have reference handy but his argument was that each __GFP_NOWARN should be explicit rather than implicit because it is a deliberate decision to make. -- Michal Hocko SUSE Labs
