linux-kernel - Re: x86, perf: throttling issues with long nmi latencies

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:	Tue, 15 Oct 2013 16:39:31 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	Don Zickus <dzickus@...hat.com>
Cc:	dave.hansen@...ux.intel.com, eranian@...gle.com,
	ak@...ux.intel.com, jmario@...hat.com,
	linux-kernel@...r.kernel.org, acme@...radead.org
Subject: Re: x86, perf: throttling issues with long nmi latencies

On Tue, Oct 15, 2013 at 10:36:31AM -0400, Don Zickus wrote:
> > > +refill:
> > > +	if (kernel_ip(ip)) {
> > > +		u8 *buf = &__get_cpu_var(insn_page[0]);
> > > +		size = PAGE_SIZE - ((unsigned long)to & (PAGE_SIZE-1));
> > > +		if (size < MAX_INSN_SIZE) {
> > > +			/*
> > > +			 * If we're going to have to touch two pages; just copy
> > > +			 * as much as we can hold.
> > > +			 */
> > > +			size = PAGE_SIZE;

> Quick thoughts?

Yeah, see the patch I just send; but notably I got the kernel_ip(ip)
case the wrong way about. See how it copies userspace memory for kernel
IPs and vice versa.


--
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/