linux-kernel - Re: Linux 3.19-rc3

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]

Date:	Sat, 10 Jan 2015 11:46:27 +0100
From:	Andreas Mohr <andi@...as.de>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	David Lang <david@...g.hm>,
	"Kirill A. Shutemov" <kirill@...temov.name>,
	Catalin Marinas <catalin.marinas@....com>,
	Mark Langsdorf <mlangsdo@...hat.com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	linux-arm-kernel@...ts.infradead.org
Subject: Re: Linux 3.19-rc3

Linus Torvalds wrote:
> I dunno. I do know that you definitely don't want to haev a
> desktop/workstation with 64kB pages.

Yet that is what any VirtualAlloc() call on Windows does
(well, not exactly *page* granularity but *allocation* granularity there).
Prime example: do a naively specific/custom VirtualAlloc() request
for a simple string Hello World\0 allocation (11+1 bytes),
get one page (4kB, "Private Data") plus "overhead" (60kB, "Unusable").
--> allocation efficiency: 0.01831%(!).
And that does hurt plenty IME, especially on a 32bit address space's
very limited 2GB/3GB total per Win32 process.

http://blogs.microsoft.co.il/sasha/2014/07/22/tracking-unusable-virtual-memory-vmmap/
"Why is address space allocation granularity 64K?"
  http://blogs.msdn.com/b/oldnewthing/archive/2003/10/08/55239.aspx

One thing less left to wonder why 'doze is such a performance pig...

Andreas Mohr
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/