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From:   "NeilBrown" <neilb@suse.de>
To:     "Michal Hocko" <mhocko@suse.com>
Cc:     linux-mm@kvack.org, "Dave Chinner" <david@fromorbit.com>,
        "Andrew Morton" <akpm@linux-foundation.org>,
        "Christoph Hellwig" <hch@infradead.org>,
        "Uladzislau Rezki" <urezki@gmail.com>,
        linux-fsdevel@vger.kernel.org,
        "LKML" <linux-kernel@vger.kernel.org>,
        "Ilya Dryomov" <idryomov@gmail.com>,
        "Jeff Layton" <jlayton@kernel.org>
Subject: Re: [PATCH 2/4] mm/vmalloc: add support for __GFP_NOFAIL
In-reply-to: <YXeoJbzICpNsEEBr@dhcp22.suse.cz>
References: <20211025150223.13621-1-mhocko@kernel.org>,
 <20211025150223.13621-3-mhocko@kernel.org>,
 <163520277623.16092.15759069160856953654@noble.neil.brown.name>,
 <YXeoJbzICpNsEEBr@dhcp22.suse.cz>
Date:   Tue, 26 Oct 2021 21:30:52 +1100
Message-id: <163524425265.8576.7853645770508739439@noble.neil.brown.name>
Precedence: bulk

On Tue, 26 Oct 2021, Michal Hocko wrote:
> On Tue 26-10-21 09:59:36, Neil Brown wrote:
> > On Tue, 26 Oct 2021, Michal Hocko wrote:
> [...]
> > > @@ -3032,6 +3036,10 @@ void *__vmalloc_node_range(unsigned long size, u=
nsigned long align,
> > >  		warn_alloc(gfp_mask, NULL,
> > >  			"vmalloc error: size %lu, vm_struct allocation failed",
> > >  			real_size);
> > > +		if (gfp_mask & __GFP_NOFAIL) {
> > > +			schedule_timeout_uninterruptible(1);
> > > +			goto again;
> > > +		}
> >=20
> > Shouldn't the retry happen *before* the warning?
>=20
> I've done it after to catch the "depleted or fragmented" vmalloc space.
> This is not related to the memory available and therefore it won't be
> handled by the oom killer. The error message shouldn't imply the vmalloc
> allocation failure IMHO but I am open to suggestions.

The word "failed" does seem to imply what you don't want it to imply...

I guess it is reasonable to have this warning, but maybe add " -- retrying"
if __GFP_NOFAIL.

Thanks,
NeilBrown