From: Rik van Riel <riel@redhat.com>
To: Stanislav Meduna <stano@meduna.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>,
Steven Rostedt <rostedt@goodmis.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
"linux-rt-users@vger.kernel.org" <linux-rt-users@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
the arch/x86 maintainers <x86@kernel.org>,
Hai Huang <hhuang@redhat.com>
Subject: Re: [PATCH] mm: fix up a spurious page fault whenever it happens
Date: Thu, 23 May 2013 08:19:38 -0400 [thread overview]
Message-ID: <519E095A.4000105@redhat.com> (raw)
In-Reply-To: <519DCE2A.4010801@meduna.org>
On 05/23/2013 04:07 AM, Stanislav Meduna wrote:
> On 22.05.2013 20:43, Rik van Riel wrote:
>
>>> Some CPUs have had errata when it comes to flushing large pages that
>>> have been split into small pages by hardware, e.g. due to MTRR
>>> conflicts. In that case, fragments of the large page may have been left
>>> in the TLB.
>
> Can I somehow find if this is the case? The memory mapping
> for the failing process has two regions slightly larger than
> 4 MB - code and heap.
>
> The process also does not access any funny memory regions
> from userspace - it is basically networking (both TCP/IP
> and raw sockets) and crunching of the data received.
> No mmapped devices or something like that.
>
>> static inline void __native_flush_tlb_single(unsigned long addr)
>> {
>> __flush_tlb();
>> }
>>
>> This on top of the other two patches.
>
> It did not crash overnight, but it also does not show any
> minor fault counted for the threads, so I'm afraid the situation
> just did not happen - there should be at least one visible in
> the ps -o min_flt output, right?
If all the page faults are done by he main thread,
and the TLB gets properly flushed now, the other
threads might not see minor faults.
> I will give it some more testing time.
That is a good idea.
Now to figure out how we properly fix this
issue in the kernel...
We can add a bit in the architecture bits that
we use to check against other CPU and system
errata, and conditionally flush the whole TLB
from __native_flush_tlb_single().
The question is, how do we identify what CPUs
need the extra flushing?
And in what circumstances do they require it?
next prev parent reply other threads:[~2013-05-23 12:20 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-17 8:42 [PATCH - sort of] x86: Livelock in handle_pte_fault Stanislav Meduna
2013-05-22 0:39 ` Steven Rostedt
2013-05-22 7:32 ` Stanislav Meduna
2013-05-22 12:33 ` Rik van Riel
2013-05-22 15:01 ` Linus Torvalds
2013-05-22 17:41 ` [PATCH] mm: fix up a spurious page fault whenever it happens Rik van Riel
2013-05-22 18:04 ` Stanislav Meduna
2013-05-22 18:11 ` Steven Rostedt
2013-05-22 18:21 ` Stanislav Meduna
2013-05-22 18:35 ` Rik van Riel
2013-05-22 18:42 ` H. Peter Anvin
2013-05-22 18:43 ` Rik van Riel
2013-05-23 8:07 ` Stanislav Meduna
2013-05-23 12:19 ` Rik van Riel [this message]
2013-05-23 13:29 ` Steven Rostedt
2013-05-23 15:06 ` H. Peter Anvin
2013-05-23 15:27 ` Steven Rostedt
2013-05-23 17:24 ` H. Peter Anvin
2013-05-23 17:36 ` Steven Rostedt
2013-05-23 17:38 ` H. Peter Anvin
2013-05-24 8:29 ` Stanislav Meduna
2013-05-24 10:28 ` Stanislav Meduna
2013-05-24 13:06 ` Rik van Riel
2013-05-24 13:55 ` Stanislav Meduna
2013-05-24 14:23 ` Stanislav Meduna
2013-06-16 21:34 ` Stanislav Meduna
2013-06-18 19:13 ` Stanislav Meduna
2013-06-19 5:20 ` Linus Torvalds
2013-06-19 7:36 ` Stanislav Meduna
2013-06-19 8:06 ` Peter Zijlstra
2013-06-20 17:50 ` Stanislav Meduna
2013-05-23 14:45 ` Linus Torvalds
2013-05-23 14:50 ` Linus Torvalds
2013-05-23 15:03 ` Stanislav Meduna
2013-05-22 18:47 ` Stanislav Meduna
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