linux-kernel - Re: [linus:master] [mseal] 8be7258aad: stress-ng.pagemove.page_remaps_per

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAHk-=wgySgXXkZtx49Xq70X2CmSizM8siacYKncMmFWRzKjs5Q@mail.gmail.com>
Date: Mon, 5 Aug 2024 12:48:03 -0700
From: Linus Torvalds <torvalds@...ux-foundation.org>
To: Jeff Xu <jeffxu@...gle.com>
Cc: Michael Ellerman <mpe@...erman.id.au>, Nicholas Piggin <npiggin@...il.com>, 
	Christophe Leroy <christophe.leroy@...roup.eu>, Pedro Falcato <pedro.falcato@...il.com>, 
	kernel test robot <oliver.sang@...el.com>, Jeff Xu <jeffxu@...omium.org>, oe-lkp@...ts.linux.dev, 
	lkp@...el.com, linux-kernel@...r.kernel.org, 
	Andrew Morton <akpm@...ux-foundation.org>, Kees Cook <keescook@...omium.org>, 
	"Liam R. Howlett" <Liam.Howlett@...cle.com>, Dave Hansen <dave.hansen@...el.com>, 
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>, Guenter Roeck <groeck@...omium.org>, 
	Jann Horn <jannh@...gle.com>, Jonathan Corbet <corbet@....net>, 
	Jorge Lucangeli Obes <jorgelo@...omium.org>, Matthew Wilcox <willy@...radead.org>, 
	Muhammad Usama Anjum <usama.anjum@...labora.com>, Stephen Röttger <sroettger@...gle.com>, 
	Suren Baghdasaryan <surenb@...gle.com>, Amer Al Shanawany <amer.shanawany@...il.com>, 
	Javier Carrasco <javier.carrasco.cruz@...il.com>, Shuah Khan <shuah@...nel.org>, 
	linux-api@...r.kernel.org, linux-mm@...ck.org, ying.huang@...el.com, 
	feng.tang@...el.com, fengwei.yin@...el.com
Subject: Re: [linus:master] [mseal] 8be7258aad: stress-ng.pagemove.page_remaps_per_sec
 -4.4% regression

On Mon, 5 Aug 2024 at 12:38, Jeff Xu <jeffxu@...gle.com> wrote:
>
> I'm curious, why does ppc need to unmap vdso ? ( other archs don't
> have unmap logic.)

I have no idea. There are comments about 'perf' getting confused about
mmap counts when 'context.vdso' isn't set up.

But x86 has the same context.vdso logic, and does *not* set the
pointer before installing the vma, for example. Also does not zero it
out on munmap(), although it does have the mremap logic.

For all I know it may all be entirely unnecessary, and could be
removed entirely.

          Linus