From: Andi Kleen <ak@suse.de>
To: Parag Warudkar <kernel-stuff@comcast.net>
Cc: Ray Fucillo <fucillo@intersystems.com>, linux-kernel@vger.kernel.org
Subject: Re: process creation time increases linearly with shmem
Date: Thu, 25 Aug 2005 16:22:08 +0200 [thread overview]
Message-ID: <200508251622.08456.ak@suse.de> (raw)
In-Reply-To: <082520051405.5272.430DD0420003F49F00001498220076139400009A9B9CD3040A029D0A05@comcast.net>
> Would it be worth trying to do something like this?
Maybe. Shouldn't be very hard though - you just need to check if the VMA is
backed by an object and if yes don't call copy_page_range for it.
I think it just needs (untested)
Index: linux-2.6.13-rc5-misc/kernel/fork.c
===================================================================
--- linux-2.6.13-rc5-misc.orig/kernel/fork.c
+++ linux-2.6.13-rc5-misc/kernel/fork.c
@@ -265,7 +265,8 @@ static inline int dup_mmap(struct mm_str
rb_parent = &tmp->vm_rb;
mm->map_count++;
- retval = copy_page_range(mm, current->mm, tmp);
+ if (!file && !is_vm_hugetlb_page(vma))
+ retval = copy_page_range(mm, current->mm, tmp);
spin_unlock(&mm->page_table_lock);
if (tmp->vm_ops && tmp->vm_ops->open)
But I'm not sure it's a good idea in all cases. Would need a lot of
benchmarking at least.
-Andi
next prev parent reply other threads:[~2005-08-25 14:22 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-08-25 14:05 process creation time increases linearly with shmem Parag Warudkar
2005-08-25 14:22 ` Andi Kleen [this message]
2005-08-25 14:35 ` Nick Piggin
2005-08-25 14:47 ` Parag Warudkar
2005-08-25 15:56 ` Andi Kleen
-- strict thread matches above, loose matches on Subject: below --
2005-12-14 14:07 Brice Oliver
2005-12-14 16:21 ` Hugh Dickins
2005-08-24 18:43 Ray Fucillo
2005-08-25 0:14 ` Nick Piggin
2005-08-25 13:07 ` Ray Fucillo
2005-08-25 13:13 ` Andi Kleen
2005-08-25 14:28 ` Nick Piggin
2005-08-25 17:31 ` Rik van Riel
2005-08-26 1:26 ` Nick Piggin
2005-08-26 1:50 ` Rik van Riel
2005-08-26 3:56 ` Linus Torvalds
2005-08-26 11:49 ` Hugh Dickins
2005-08-26 14:26 ` Nick Piggin
2005-08-26 17:00 ` Ray Fucillo
2005-08-26 17:53 ` Rik van Riel
2005-08-26 18:20 ` Ross Biro
2005-08-26 18:56 ` Hugh Dickins
[not found] ` <8783be660508260915524e2b1e@mail.gmail.com>
2005-08-26 16:38 ` Hugh Dickins
2005-08-26 16:43 ` Ross Biro
2005-08-26 18:07 ` Linus Torvalds
2005-08-26 18:41 ` Hugh Dickins
2005-08-26 22:55 ` Linus Torvalds
2005-08-26 23:10 ` Rik van Riel
2005-08-26 23:23 ` Linus Torvalds
2005-08-27 15:05 ` Nick Piggin
2005-08-28 4:26 ` Hugh Dickins
2005-08-28 6:49 ` Nick Piggin
2005-08-29 23:33 ` Ray Fucillo
2005-08-30 0:29 ` Nick Piggin
2005-08-30 1:03 ` Linus Torvalds
2005-08-30 0:34 ` Linus Torvalds
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