Messages in this thread | | | From | Michael Kerrisk <> | Date | Sat, 19 Jun 2010 15:43:28 +0200 | Subject | Re: [PATCH] [31/31] HWPOISON: Add a madvise() injector for soft page offlining |
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Hi Andi,
On Sat, Jun 19, 2010 at 3:30 PM, Andi Kleen <andi@firstfloor.org> wrote: > On Sat, Jun 19, 2010 at 03:25:16PM +0200, Michael Kerrisk wrote: >> Hi Andi, >> >> Thanks for this. Some comments below. >> >> On Sat, Jun 19, 2010 at 3:20 PM, Andi Kleen <andi@firstfloor.org> wrote: >> > On Sat, Jun 19, 2010 at 02:36:28PM +0200, Michael Kerrisk wrote: >> >> Hi Andi, >> >> >> >> On Tue, Dec 8, 2009 at 11:16 PM, Andi Kleen <andi@firstfloor.org> wrote: >> >> > >> >> > Process based injection is much easier to handle for test programs, >> >> > who can first bring a page into a specific state and then test. >> >> > So add a new MADV_SOFT_OFFLINE to soft offline a page, similar >> >> > to the existing hard offline injector. >> >> >> >> I see that this made its way into 2.6.33. Could you write a short >> >> piece on it for the madvise.2 man page? >> > >> > Also fixed the previous snippet slightly. >> >> (thanks) >> >> > commit edb43354f0ffc04bf4f23f01261f9ea9f43e0d3d >> > Author: Andi Kleen <ak@linux.intel.com> >> > Date: Sat Jun 19 15:19:28 2010 +0200 >> > >> > MADV_SOFT_OFFLINE >> > >> > Signed-off-by: Andi Kleen <ak@linux.intel.com> >> > >> > diff --git a/man2/madvise.2 b/man2/madvise.2 >> > index db29feb..9dccd97 100644 >> > --- a/man2/madvise.2 >> > +++ b/man2/madvise.2 >> > @@ -154,7 +154,15 @@ processes. >> > This operation may result in the calling process receiving a >> > .B SIGBUS >> > and the page being unmapped. >> > -This feature is intended for memory testing. >> > +This feature is intended for testing of memory error handling code. >> > +This feature is only available if the kernel was configured with >> > +.BR CONFIG_MEMORY_FAILURE . >> > +.TP >> > +.BR MADV_SOFT_OFFLINE " (Since Linux 2.6.33) >> > +Soft offline a page. This will result in the memory of the page >> > +being copied to a new page and original page be offlined. The operation >> >> Can you explain the term "offlined" please. > > The memory is not used anymore and taken out of normal > memory management (until unpoisoned)
Is there a userspace operation to unpoison (i.e., reverse MADV_SOFT_OFFLINE)?
I ask because I wondered if there is something additional to be documented.
> and the "HardwareCorrupted:" counter in /proc/meminfo increases > > (don't put the later in, I'm thinking about changing that)
Okay.
>> >> > +should be transparent to the calling process. >> >> Does "should be transparent" mean "is normally invisible"? > > Yes. It's similar to being swapped out and swapped in again.
Okay.
Thanks,
Michael
-- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Author of "The Linux Programming Interface" http://blog.man7.org/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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