linux-kernel - Re: [PATCH v4] introduce macro spin_event

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: <49B9362D.3090805@freescale.com>
Date:	Thu, 12 Mar 2009 11:19:57 -0500
From:	Timur Tabi <timur@...escale.com>
To:	Grant Likely <grant.likely@...retlab.ca>
CC:	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Alan Cox <alan@...rguk.ukuu.org.uk>,
	linux-kernel@...r.kernel.org, rdreier@...co.com,
	jirislaby@...il.com, peterz@...radead.org, will.newton@...il.com,
	hancockrwd@...il.com, jeremy@...p.org
Subject: Re: [PATCH v4] introduce macro spin_event_timeout()

Grant Likely wrote:

> #define spin_until_timeout(condition, timeout, rc)          \
>       for (unsigned long __timeout = jiffies + (timeout);     \
>               (!(rc = (condition)) && time_after(jiffies, __timeout)); )

Ooo, that's good.

I'm still not crazy about using jiffies, since it doesn't get
incremented when interrupts are disabled, and I'd like this function to
work in those cases.  How about get_cycles()?  I know it's not supported
on all platforms, but I'm willing to live with that.

The other problem with get_cycles() is that there doesn't appear to be a
num_cycles_per_usec() function, so there's no way for me to scale the
count to a fixed time period.

-- 
Timur Tabi
Linux kernel developer at Freescale
--
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/