From: Andrew Morton <akpm@linux-foundation.org>
To: Hugh Dickins <hughd@google.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 2/12] mm: let swap use exceptional entries
Date: Sat, 18 Jun 2011 14:55:46 -0700 [thread overview]
Message-ID: <20110618145546.12e175bf.akpm@linux-foundation.org> (raw)
In-Reply-To: <alpine.LSU.2.00.1106140342330.29206@sister.anvils>
On Tue, 14 Jun 2011 03:43:47 -0700 (PDT) Hugh Dickins <hughd@google.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?
WARNING: multiple messages have this Message-ID (diff)
From: Andrew Morton <akpm@linux-foundation.org>
To: Hugh Dickins <hughd@google.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 2/12] mm: let swap use exceptional entries
Date: Sat, 18 Jun 2011 14:55:46 -0700 [thread overview]
Message-ID: <20110618145546.12e175bf.akpm@linux-foundation.org> (raw)
In-Reply-To: <alpine.LSU.2.00.1106140342330.29206@sister.anvils>
On Tue, 14 Jun 2011 03:43:47 -0700 (PDT) Hugh Dickins <hughd@google.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?
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next prev parent reply other threads:[~2011-06-18 21:55 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-14 10:40 [PATCH 0/12] tmpfs: convert from old swap vector to radix tree Hugh Dickins
2011-06-14 10:40 ` Hugh Dickins
2011-06-14 10:42 ` [PATCH 1/12] radix_tree: exceptional entries and indices Hugh Dickins
2011-06-14 10:42 ` Hugh Dickins
2011-06-14 11:22 ` Pekka Enberg
2011-06-14 11:22 ` Pekka Enberg
2011-06-15 0:24 ` Hugh Dickins
2011-06-17 23:38 ` Andrew Morton
2011-06-17 23:38 ` Andrew Morton
2011-06-18 0:07 ` Randy Dunlap
2011-06-18 0:07 ` Randy Dunlap
2011-06-18 0:12 ` Randy Dunlap
2011-06-18 0:12 ` Randy Dunlap
2011-06-18 1:52 ` Hugh Dickins
2011-06-18 1:52 ` Hugh Dickins
2011-07-19 22:36 ` Hugh Dickins
2011-07-19 22:36 ` Hugh Dickins
2011-07-19 23:28 ` Randy Dunlap
2011-07-19 23:28 ` Randy Dunlap
2011-06-18 0:13 ` Hugh Dickins
2011-06-18 0:13 ` Hugh Dickins
2011-06-18 21:48 ` Andrew Morton
2011-06-18 21:48 ` Andrew Morton
2011-07-12 22:56 ` Hugh Dickins
2011-07-12 22:56 ` Hugh Dickins
2011-07-12 23:24 ` Andrew Morton
2011-07-12 23:24 ` Andrew Morton
2011-07-13 22:27 ` Hugh Dickins
2011-07-13 22:27 ` Hugh Dickins
2011-06-14 10:43 ` [PATCH 2/12] mm: let swap use exceptional entries Hugh Dickins
2011-06-14 10:43 ` Hugh Dickins
2011-06-18 21:52 ` Andrew Morton
2011-06-18 21:52 ` Andrew Morton
2011-07-12 22:08 ` Hugh Dickins
2011-07-12 22:08 ` Hugh Dickins
2011-07-13 23:11 ` Andrew Morton
2011-07-13 23:11 ` Andrew Morton
2011-07-19 22:46 ` Hugh Dickins
2011-07-19 22:46 ` Hugh Dickins
2011-06-18 21:55 ` Andrew Morton [this message]
2011-06-18 21:55 ` Andrew Morton
2011-07-12 22:35 ` Hugh Dickins
2011-07-12 22:35 ` Hugh Dickins
2011-06-14 10:45 ` [PATCH 3/12] tmpfs: demolish old swap vector support Hugh Dickins
2011-06-14 10:45 ` Hugh Dickins
2011-06-14 10:48 ` [PATCH 4/12] tmpfs: miscellaneous trivial cleanups Hugh Dickins
2011-06-14 10:48 ` Hugh Dickins
2011-06-14 10:49 ` [PATCH 5/12] tmpfs: copy truncate_inode_pages_range Hugh Dickins
2011-06-14 10:49 ` Hugh Dickins
2011-06-14 10:51 ` [PATCH 6/12] tmpfs: convert shmem_truncate_range to radix-swap Hugh Dickins
2011-06-14 10:51 ` Hugh Dickins
2011-06-14 10:52 ` [PATCH 7/12] tmpfs: convert shmem_unuse_inode " Hugh Dickins
2011-06-14 10:52 ` Hugh Dickins
2011-06-14 10:53 ` [PATCH 8/12] tmpfs: convert shmem_getpage_gfp " Hugh Dickins
2011-06-14 10:53 ` Hugh Dickins
2011-06-14 10:54 ` [PATCH 9/12] tmpfs: convert mem_cgroup shmem " Hugh Dickins
2011-06-14 10:54 ` Hugh Dickins
2011-06-14 10:56 ` [PATCH 10/12] tmpfs: convert shmem_writepage and enable swap Hugh Dickins
2011-06-14 10:56 ` Hugh Dickins
2011-06-14 10:57 ` [PATCH 11/12] tmpfs: use kmemdup for short symlinks Hugh Dickins
2011-06-14 10:57 ` Hugh Dickins
2011-06-14 11:16 ` Pekka Enberg
2011-06-14 11:16 ` Pekka Enberg
2011-06-14 10:59 ` [PATCH 12/12] mm: a few small updates for radix-swap Hugh Dickins
2011-06-14 10:59 ` Hugh Dickins
2011-06-15 0:49 ` [PATCH v2 " Hugh Dickins
2011-06-15 0:49 ` Hugh Dickins
2011-06-14 17:29 ` [PATCH 0/12] tmpfs: convert from old swap vector to radix tree Linus Torvalds
2011-06-14 17:29 ` Linus Torvalds
2011-06-14 18:20 ` Rik van Riel
2011-06-14 18:20 ` Rik van Riel
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