From: Seth Jennings <sjenning@linux•vnet.ibm.com>
To: Benjamin Herrenschmidt <benh@kernel•crashing.org>
Cc: Brian King <brking@linux•vnet.ibm.com>,
Robert Jennings <rcj@linux•vnet.ibm.com>,
linuxppc-dev@lists•ozlabs.org, Nitin Gupta <ngupta@vflare•org>,
Dave Hansen <dave@linux•vnet.ibm.com>
Subject: Re: tlb flushing on Power
Date: Wed, 08 Feb 2012 11:39:32 -0600 [thread overview]
Message-ID: <4F32B354.7030306@linux.vnet.ibm.com> (raw)
In-Reply-To: <1327613953.24487.9.camel@pasglop>
Hey Ben,
Thanks for responding.
On 01/26/2012 03:39 PM, Benjamin Herrenschmidt wrote:
> On Thu, 2012-01-26 at 08:41 -0600, Brian King wrote:
>> CC'ing linuxppc-dev...
>>
>>
>> On 01/26/2012 08:18 AM, Seth Jennings wrote:
>>> Hey Dave,
>>>
>>> So I submitted the zsmalloc patches to lkml at the beginning
>>> of the year
>>>
>>> https://lkml.org/lkml/2012/1/9/389
>>>
>>> I found there are two functions Nitin used in the mapping
>>> functions that are not supported in the powerpc arch:
>>> set_pte() and __flush_tlb_one().
>
> .../...
>
> The arch management of page tables can be tricky indeed :-) I need to
> have a better understanding of what you are doing to see how I can try
> to adapt it to power.
You can look at https://lkml.org/lkml/2012/1/9/389 in zsmalloc-main.c,
zs_[un]map_object() functions for the currently uses of set_pte() and
__flush_tlb_one().
> set_pte() is long gone on all archs really (or if it's still there it's
> not meant to be used as is), use set_pte_at().
Problem with set_pte_at() for us is that we don't have an mm_struct to pass
because the mapping is not for a userspace process but for the kernel itself.
However, I do think this is the portable function we need to be using. Just
need to figure out what to pass in for the mm_struct param.
> __flush_tlb_one() doesn't mean anything as an arch independent
> functionality. We have a local_flush_tlb_page() that -might- do what you
> want but why in hell is that patch not using proper existing
> interfaces ?
flush_tlb_page() is the portable function we should be using. However,
again, it requires a vma_area_struct. I'm not sure what we should be
passing there.
--
Seth
next prev parent reply other threads:[~2012-02-08 17:40 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <4F2160B3.60708@linux.vnet.ibm.com>
2012-01-26 14:41 ` tlb flushing on Power Brian King
2012-01-26 21:39 ` Benjamin Herrenschmidt
2012-01-26 22:30 ` Dave Hansen
2012-01-27 2:40 ` Benjamin Herrenschmidt
2012-02-08 17:39 ` Seth Jennings [this message]
2012-02-08 21:04 ` Benjamin Herrenschmidt
2012-02-10 19:14 ` Seth Jennings
2012-02-16 17:11 ` Seth Jennings
2012-02-16 20:31 ` Benjamin Herrenschmidt
2012-03-05 17:56 ` Seth Jennings
2012-03-07 5:28 ` Michael Neuling
2012-03-07 21:18 ` Seth Jennings
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