From: Andrew Morton <akpm@osdl.org>
To: Hugh Dickins <hugh@veritas.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH 04/21] mm: zap_pte_range dont dirty anon
Date: Sun, 25 Sep 2005 23:14:24 -0700 [thread overview]
Message-ID: <20050925231424.6c08bc8a.akpm@osdl.org> (raw)
In-Reply-To: <Pine.LNX.4.61.0509260659370.8065@goblin.wat.veritas.com>
Hugh Dickins <hugh@veritas.com> wrote:
>
> > What is the page is (for example) clean swapcache, having been recently
> > faulted in. If this pte indicates that this process has modified the page
> > and we don't run set_page_dirty(), the page could be reclaimed and the
> > change is lost.
>
> Absolutely. But either the page is unique to this mm, shared only with
> swapcache: in which case we're about to do a free_swap_cache on it (that
> may be delayed in actually freeing the swap because of not getting page
> lock, presumably because vmscan just got to it, but no matter), and we
> don't care at all that the page no longer represents what's on swap disk.
>
> Or, the page is shared with another mm. But it's an anonymous page
> (a private page), so it's shared via fork, and COW applies to it.
mmap(MAP_ANONYMOUS|MAP_SHARED)
fork()
swapout
swapin
swapoff
Now we have two mm's sharing a clean, non-cowable, non-swapcache anonymous
page, no?
next prev parent reply other threads:[~2005-09-26 6:15 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-09-25 15:46 [PATCH 00/21] mm: page fault scalability prep Hugh Dickins
2005-09-25 15:47 ` [PATCH 01/21] mm: hugetlb truncation fixes Hugh Dickins
2005-09-25 15:48 ` [PATCH 02/21] mm: copy_pte_range progress fix Hugh Dickins
2005-09-25 15:49 ` [PATCH 03/21] mm: msync_pte_range progress Hugh Dickins
2005-09-25 15:49 ` [PATCH 04/21] mm: zap_pte_range dont dirty anon Hugh Dickins
2005-09-25 22:26 ` Andrew Morton
2005-09-26 6:02 ` Hugh Dickins
2005-09-26 6:14 ` Andrew Morton [this message]
2005-09-26 7:20 ` Hugh Dickins
2005-09-25 15:51 ` [PATCH 05/21] mm: anon is already wrprotected Hugh Dickins
2005-09-25 15:52 ` [PATCH 06/21] mm: vm_stat_account unshackled Hugh Dickins
2005-09-25 15:53 ` [PATCH 07/21] mm: remove_vma_list consolidation Hugh Dickins
2005-09-25 15:53 ` [PATCH 08/21] mm: unlink_file_vma, remove_vma Hugh Dickins
2005-09-25 15:54 ` [PATCH 09/21] mm: exit_mmap need not reset Hugh Dickins
2005-09-25 15:56 ` [PATCH 10/21] mm: page fault handlers tidyup Hugh Dickins
2005-09-25 15:57 ` [PATCH 11/21] mm: move_page_tables by extents Hugh Dickins
2005-09-25 15:59 ` [PATCH 12/21] mm: tlb_gather_mmu get_cpu_var Hugh Dickins
2005-09-25 16:01 ` [PATCH 13/21] mm: tlb_is_full_mm was obscure Hugh Dickins
2005-09-25 16:03 ` [PATCH 14/21] mm: tlb_finish_mmu forget rss Hugh Dickins
2005-09-25 16:06 ` [PATCH 15/21] mm: mm_init set_mm_counters Hugh Dickins
2005-09-25 16:07 ` [PATCH 16/21] mm: rss = file_rss + anon_rss Hugh Dickins
2005-09-25 16:08 ` [PATCH 17/21] mm: batch updating mm_counters Hugh Dickins
2005-09-26 7:25 ` Nick Piggin
2005-09-26 8:42 ` Hugh Dickins
2005-09-25 16:09 ` [PATCH 18/21] mm: dup_mmap use oldmm more Hugh Dickins
2005-09-25 16:10 ` [PATCH 19/21] mm: dup_mmap down new mmap_sem Hugh Dickins
2005-09-25 16:11 ` [PATCH 20/21] mm: sh64 hugetlbpage.c Hugh Dickins
2005-09-29 7:00 ` Paul Mundt
2005-09-25 16:15 ` [PATCH 21/21] mm: m68k kill stram swap Hugh Dickins
2005-09-28 0:05 ` [PATCH 00/21] mm: page fault scalability prep Christoph Lameter
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