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: Fri, 10 Feb 2012 13:14:06 -0600 [thread overview]
Message-ID: <4F356C7E.3070608@linux.vnet.ibm.com> (raw)
In-Reply-To: <1328735054.2903.29.camel@pasglop>
On 02/08/2012 03:04 PM, Benjamin Herrenschmidt wrote:
>
>> 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.
>
> Then use init_mm
Thanks, that's what I was looking for.
>> 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.
>
> Do you need this to be CPU local flush or global ? In the later,
> flush_tlb_kernel_range() is the right API.
>
> If you want per-cpu, we'll have to add a new arch hook.
We have interrupts disabled, due to the get_cpu_var() on the percpu variable
zs_map_area in zs_map_object(), while the allocation is mapped. So a CPU local
would be what we need.
--
Seth
next prev parent reply other threads:[~2012-02-10 19:14 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
2012-02-08 21:04 ` Benjamin Herrenschmidt
2012-02-10 19:14 ` Seth Jennings [this message]
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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