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Message-ID: <20170106123117.GL5556@dhcp22.suse.cz> Date: Fri, 6 Jan 2017 13:31:17 +0100 From: Michal Hocko <mhocko@...nel.org> To: Vlastimil Babka <vbabka@...e.cz> Cc: Andrew Morton <akpm@...ux-foundation.org>, David Rientjes <rientjes@...gle.com>, Mel Gorman <mgorman@...e.de>, Johannes Weiner <hannes@...xchg.org>, Al Viro <viro@...iv.linux.org.uk>, linux-mm@...ck.org, LKML <linux-kernel@...r.kernel.org>, kvm@...r.kernel.org, linux-f2fs-devel@...ts.sourceforge.net, linux-security-module@...r.kernel.org, linux-ext4@...r.kernel.org, Joe Perches <joe@...ches.com>, Anatoly Stepanov <astepanov@...udlinux.com>, Paolo Bonzini <pbonzini@...hat.com>, Mike Snitzer <snitzer@...hat.com>, "Michael S. Tsirkin" <mst@...hat.com>, Theodore Ts'o <tytso@....edu>, Andreas Dilger <adilger@...ger.ca> Subject: Re: [PATCH] mm: support __GFP_REPEAT in kvmalloc_node On Fri 06-01-17 13:09:36, Vlastimil Babka wrote: > On 01/04/2017 07:12 PM, Michal Hocko wrote: [...] > > diff --git a/mm/util.c b/mm/util.c > > index 8e4ea6cbe379..a2bfb85e60e5 100644 > > --- a/mm/util.c > > +++ b/mm/util.c > > @@ -348,8 +348,13 @@ void *kvmalloc_node(size_t size, gfp_t flags, int node) > > * Make sure that larger requests are not too disruptive - no OOM > > * killer and no allocation failure warnings as we have a fallback > > */ > > - if (size > PAGE_SIZE) > > - kmalloc_flags |= __GFP_NORETRY | __GFP_NOWARN; > > + if (size > PAGE_SIZE) { > > + kmalloc_flags |= __GFP_NOWARN; > > + > > + if (!(kmalloc_flags & __GFP_REPEAT) || > > + (size <= PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)) > > + kmalloc_flags |= __GFP_NORETRY; > > I think this would be more understandable for me if it was written in > the opposite way, i.e. "if we have costly __GFP_REPEAT allocation, don't > use __GFP_NORETRY", Dunno, doesn't look much simpler to me kmalloc_flags |= __GFP_NORETRY; if ((kmalloc_flags & __GFP_REPEAT) && (size > PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)) { kmalloc_flags &= ~__GFP_NORETRY; } > but nevermind, seems correct to me wrt current > handling of both flags in the page allocator. And it serves as a good > argument to have this wrapper in mm/ as we are hopefully more likely to > keep it working as intended with future changes, than all the opencoded > variants. > > Acked-by: Vlastimil Babka <vbabka@...e.cz> Thanks! -- Michal Hocko SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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