From: Michal Hocko <mhocko@kernel.org>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Dave Chinner <david@fromorbit.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
linux-fsdevel@vger.kernel.org, Ming Lei <ming.lei@canonical.com>
Subject: Re: __vmalloc() vs. GFP_NOIO/GFP_NOFS
Date: Tue, 5 Jan 2016 16:35:01 +0100 [thread overview]
Message-ID: <20160105153501.GB15594@dhcp22.suse.cz> (raw)
In-Reply-To: <20160103203514.GN9938@ZenIV.linux.org.uk>
On Sun 03-01-16 20:35:14, Al Viro wrote:
[...]
> BTW, far scarier one is not GFP_NOFS or GFP_IO - there's a weird
> caller passing GFP_ATOMIC to __vmalloc(), for no reason I can guess.
>
> _That_ really couldn't be handled without passing gfp_t to page allocation
> primitives, but I very much doubt that it's needed there at all; it's in
> alloc_large_system_hash() and I really cannot imagine a situation when
> it would be used in e.g. a nonblocking context.
Yeah, this is an __init context. The original commit which has added it
doesn't explain GFP_ATOMIC at all. It just converted alloc_bootmem to
__vmalloc resp. __get_free_pages based on the size. So we can only guess
it wanted to (ab)use memory reserves.
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2016-01-05 15:35 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-03 7:12 __vmalloc() vs. GFP_NOIO/GFP_NOFS Al Viro
2016-01-03 16:56 ` Al Viro
2016-01-03 20:12 ` Dave Chinner
2016-01-03 20:35 ` Al Viro
2016-01-05 15:35 ` Michal Hocko [this message]
2016-01-04 13:40 ` Tetsuo Handa
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