linux-kernel - Re: [PATCH 2/12] mm: let swap use exceptional entries

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20110618145546.12e175bf.akpm@linux-foundation.org>
Date:	Sat, 18 Jun 2011 14:55:46 -0700
From:	Andrew Morton <akpm@...ux-foundation.org>
To:	Hugh Dickins <hughd@...gle.com>
Cc:	linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [PATCH 2/12] mm: let swap use exceptional entries

On Tue, 14 Jun 2011 03:43:47 -0700 (PDT) Hugh Dickins <hughd@...gle.com> wrote:

> In an i386 kernel this limits its information (type and page offset)
> to 30 bits: given 32 "types" of swapfile and 4kB pagesize, that's
> a maximum swapfile size of 128GB.  Which is less than the 512GB we
> previously allowed with X86_PAE (where the swap entry can occupy the
> entire upper 32 bits of a pte_t), but not a new limitation on 32-bit
> without PAE; and there's not a new limitation on 64-bit (where swap
> filesize is already limited to 16TB by a 32-bit page offset).

hm.

>  Thirty
> areas of 128GB is probably still enough swap for a 64GB 32-bit machine.

What if it was only one area?  128GB is close enough to 64GB (or, more
realistically, 32GB) to be significant.  For the people out there who
are using a single 200GB swap partition and actually needed that much,
what happens?  swapon fails?

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/