From mboxrd@z Thu Jan 1 00:00:00 1970 MIME-Version: 1.0 In-Reply-To: References: <20151125160347.GN20646@sigint.cs.purdue.edu> <79F2255E-5E76-43E8-83B3-0DFB2CD34AC7@bitblocks.com> <3175949A-26D0-4C4A-BB7D-4E5A3EA7F8B7@me.com> Date: Thu, 26 Nov 2015 18:46:12 +0200 Message-ID: From: Alexandru Gheorghe To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net> Content-Type: multipart/alternative; boundary=001a1140df260d13e50525745034 Subject: Re: [9fans] Undefined Behaviour in C Topicbox-Message-UUID: 77d4b404-ead9-11e9-9d60-3106f5b1d025 --001a1140df260d13e50525745034 Content-Type: text/plain; charset=UTF-8 On Nov 26, 2015 6:35 PM, "erik quanstrom" wrote: > > By the way, are there any structs more than 4K in Linux? Are there any in plan 9? > > since that 4k is really pagesz, on amd64 that would be 2mb. there's no compelling reason on > 64-bit machines to start at the bottom instead of the middle. IIRC i think there was a special case with PAE as well so to speak for Linux where 36-bit is used from CPU. I remember that in that case pud, pmd and pgd are used but 0 page map is treated as a more kernel specific implementation Though i might be wrong. --001a1140df260d13e50525745034 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable


On Nov 26, 2015 6:35 PM, "erik quanstrom" <quanstro@quanstro.net> wrote:

> > By the way, are there any structs more than 4K in = Linux? Are there any in plan 9?
>
> since that 4k is really pagesz, on amd64 that would be 2mb.=C2=A0 ther= e's no compelling reason on
> 64-bit machines to start at the bottom instead of the middle.

IIRC i think there was a special case with PAE as well so to= speak for Linux where 36-bit is used from CPU. I remember that in that cas= e pud, pmd and pgd are used but 0 page map is treated as a more kernel spec= ific implementation

Though i might be wrong.

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