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From: "Jan Mikkelsen" <janm@transactionware.com>
To: "'Igor Sysoev'" <is@rambler-co.ru>,
	<freebsd-current@freebsd.org>
References: <20071009125001.GC5758@rambler-co.ru>	<20071010055748.GA18931@rambler-co.ru>
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Date: Wed, 10 Oct 2007 16:28:36 +1000
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Subject: RE: sendfile and page usage statistics
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Hi,

Igor Sysoev wrote:
> As I understand the following patch against uipc_syscalls.c
> should fix the bug to some extent:
> 
>                          if (pg->valid && vm_page_is_valid(pg,
> pgoff, xfsize))
> +                                vm_page_flag_set(pg,
> PG_REFERENCED);
>                                  VM_OBJECT_UNLOCK(obj);
>                          else if (m != NULL)
> 

Without knowing anything at all about the surrounding code, I
suspect this patch is missing some braces.  The change should
probably look like this:

                        if (pg->valid && vm_page_is_valid(pg,
pgoff, xfsize)) {
                                vm_page_flag_set(pg,
PG_REFERENCED);
                                VM_OBJECT_UNLOCK(obj);
                        } else if (m != NULL)

I don't think you'll get the behaviour you expect with your change.

Regards,

Jan Mikkelsen