| 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
| ||
|
Date: Mon, 17 May 2010 13:20:51 -0700 (PDT) From: Linus Torvalds <torvalds@...ux-foundation.org> To: Jamie Lokier <jamie@...reable.org> cc: Anton Blanchard <anton@...ba.org>, akpm@...ux-foundation.org, willy@...ux.intel.com, benh@...nel.crashing.org, paulus@...ba.org, linux-arch@...r.kernel.org, linux-kernel@...r.kernel.org Subject: Re: [PATCH 2/2]: atomic_t: Remove volatile from atomic_t definition On Mon, 17 May 2010, Jamie Lokier wrote: > > I wonder if > > extern unsigned long __nv_jiffies; > #define jiffies (*(volatile unsigned long *)*__nv_jiffies) > > would improve any code in the same way as this atomic_t change. We effectively already do that. The full 64-bit jiffies isn't volatile. But for legacy reasons, we have that "word-sized subpart" of the full counter that is volatile - and we're using linker tricks rather the the C preprocessor to do the above thing. So no, there's no room for improvement for jiffies - the only people who ever use the volatile jiffies are things that read it. There are no initializers that matter, and the updates (which also tend to suck with "volatile" because gcc just doesn't do even the obvious optimizations) are all done locked and to the non-volatile jiffies_64. Linus -- 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/
Powered by blists - more mailing lists