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Date: Wed, 26 Feb 2020 15:12:32 -0800
Subject: Re: svn commit: r358317 - head/sys/kern
From: Ravi Pokala <rpokala@freebsd.org>
To: Gleb Smirnoff <glebius@freebsd.org>
CC: <src-committers@freebsd.org>, <svn-src-all@freebsd.org>,
 <svn-src-head@freebsd.org>
Message-ID: <FB73859F-402B-4766-9937-363DCEA8E19A@panasas.com>
Thread-Topic: svn commit: r358317 - head/sys/kern
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-----Original Message-----
From: Gleb Smirnoff <glebius@freebsd.org>
Date: 2020-02-26, Wednesday at 13:55
To: Ravi Pokala <rpokala@freebsd.org>
Cc: <src-committers@freebsd.org>, <svn-src-all@freebsd.org>, <svn-src-head@freebsd.org>
Subject: Re: svn commit: r358317 - head/sys/kern

    On Tue, Feb 25, 2020 at 12:02:29PM -0800, Ravi Pokala wrote:
    R>       When sendfile_swapin() sweeps through pages in search for a bogus page
    R>       skip first and last pages.  This is a micro optimisation.
    R> 
    R> Yes, but *why* skip the first and last pages?
    
    We may have inserted bogus pages in the middle of a request. We never substitute
    first or last.
    
    -- 
    Gleb Smirnoff

Oh god, "bogus_page" -- Panasas had to jump through a bunch of hoops involving bogus_page and our RAIDing-across-sectors GEOM class years ago. <shudder>

-Ravi (rpokala@)