From: Mike Kravetz <mike.kravetz@oracle.com>
To: Sam Ravnborg <sam@ravnborg.org>
Cc: sparclinux@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org,
"David S . Miller" <davem@davemloft.net>,
Bob Picco <bob.picco@oracle.com>,
Nitin Gupta <nitin.m.gupta@oracle.com>,
Vijay Kumar <vijay.ac.kumar@oracle.com>,
Julian Calaby <julian.calaby@gmail.com>,
Adam Buchbinder <adam.buchbinder@gmail.com>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Michal Hocko <mhocko@suse.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [RFC PATCH 02/14] sparc64: add new fields to mmu context for shared context support
Date: Sun, 18 Dec 2016 15:45:31 -0800 [thread overview]
Message-ID: <a38312fe-27ed-56c6-862e-8bb53b929f2b@oracle.com> (raw)
In-Reply-To: <20161217073813.GB23567@ravnborg.org>
On 12/16/2016 11:38 PM, Sam Ravnborg wrote:
> Hi Mike
>
>> diff --git a/arch/sparc/include/asm/mmu_context_64.h b/arch/sparc/include/asm/mmu_context_64.h
>> index b84be67..d031799 100644
>> --- a/arch/sparc/include/asm/mmu_context_64.h
>> +++ b/arch/sparc/include/asm/mmu_context_64.h
>> @@ -35,15 +35,15 @@ void __tsb_context_switch(unsigned long pgd_pa,
>> static inline void tsb_context_switch(struct mm_struct *mm)
>> {
>> __tsb_context_switch(__pa(mm->pgd),
>> - &mm->context.tsb_block[0],
>> + &mm->context.tsb_block[MM_TSB_BASE],
>> #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
>> - (mm->context.tsb_block[1].tsb ?
>> - &mm->context.tsb_block[1] :
>> + (mm->context.tsb_block[MM_TSB_HUGE].tsb ?
>> + &mm->context.tsb_block[MM_TSB_HUGE] :
>> NULL)
>> #else
>> NULL
>> #endif
>> - , __pa(&mm->context.tsb_descr[0]));
>> + , __pa(&mm->context.tsb_descr[MM_TSB_BASE]));
>> }
>>
> This is a nice cleanup that has nothing to do with your series.
> Could you submit this as a separate patch so we can get it applied.
>
> This is the only place left where the array index for tsb_block
> and tsb_descr uses hardcoded values. And it would be good to get
> rid of these.
Sure, I will submit a separate cleanup patch for this.
However, do note that in my series if CONFIG_SHARED_MMU_CTX is defined,
then MM_TSB_HUGE_SHARED is index 0, instead of MM_TSB_BASE being 0 in
the case where CONFIG_SHARED_MMU_CTX is not defined. This may seem
'strange' and the obvious question would be 'why not put CONFIG_SHARED_MMU_CTX
at the end of the existing array (index 2)?'. The reason is that tsb_descr
array can not have any 'holes' when passed to the hypervisor. Since there
will always be a MM_TSB_BASE tsb, with MM_TSB_HUGE_SHARED before and
MM_TSB_HUGE after MM_TSB_BASE, few tricks are necessary to ensure no holes
are in the array passed to the hypervisor.
--
Mike Kravetz
next prev parent reply other threads:[~2016-12-18 23:46 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-16 18:35 [RFC PATCH 00/14] sparc64 shared context/TLB support Mike Kravetz
2016-12-16 18:35 ` [RFC PATCH 01/14] sparc64: placeholder for needed mmu shared context patching Mike Kravetz
2016-12-16 18:35 ` [RFC PATCH 02/14] sparc64: add new fields to mmu context for shared context support Mike Kravetz
2016-12-17 7:34 ` Sam Ravnborg
2016-12-18 23:33 ` Mike Kravetz
2016-12-21 18:12 ` Sam Ravnborg
2016-12-17 7:38 ` Sam Ravnborg
2016-12-18 23:45 ` Mike Kravetz [this message]
2016-12-21 18:13 ` Sam Ravnborg
2016-12-16 18:35 ` [RFC PATCH 03/14] sparc64: routines for basic mmu shared context structure management Mike Kravetz
2016-12-18 3:07 ` David Miller
2016-12-16 18:35 ` [RFC PATCH 04/14] sparc64: load shared id into context register 1 Mike Kravetz
2016-12-17 7:45 ` Sam Ravnborg
2016-12-19 0:22 ` Mike Kravetz
2016-12-21 18:16 ` Sam Ravnborg
2016-12-18 3:14 ` David Miller
2016-12-19 0:06 ` Mike Kravetz
2016-12-20 18:33 ` David Miller
2016-12-20 20:27 ` Mike Kravetz
2016-12-21 18:17 ` Sam Ravnborg
2016-12-16 18:35 ` [RFC PATCH 05/14] sparc64: Add PAGE_SHR_CTX flag Mike Kravetz
2016-12-18 3:12 ` David Miller
2016-12-19 0:42 ` Mike Kravetz
2016-12-20 18:33 ` David Miller
2016-12-16 18:35 ` [RFC PATCH 06/14] sparc64: general shared context tsb creation and support Mike Kravetz
2016-12-17 7:53 ` Sam Ravnborg
2016-12-19 0:52 ` Mike Kravetz
2016-12-16 18:35 ` [RFC PATCH 07/14] sparc64: move COMPUTE_TAG_TARGET and COMPUTE_TSB_PTR to header file Mike Kravetz
2016-12-16 18:35 ` [RFC PATCH 08/14] sparc64: shared context tsb handling at context switch time Mike Kravetz
2016-12-16 18:35 ` [RFC PATCH 09/14] sparc64: TLB/TSB miss handling for shared context Mike Kravetz
2016-12-16 18:35 ` [RFC PATCH 10/14] mm: add shared context to vm_area_struct Mike Kravetz
2016-12-16 18:35 ` [RFC PATCH 11/14] sparc64: add routines to look for vmsa which can share context Mike Kravetz
2016-12-16 18:35 ` [RFC PATCH 12/14] mm: add mmap and shmat arch hooks for shared context Mike Kravetz
2016-12-16 18:35 ` [RFC PATCH 13/14] sparc64 mm: add shared context support to mmap() and shmat() APIs Mike Kravetz
2016-12-16 18:35 ` [RFC PATCH 14/14] sparc64: add SHARED_MMU_CTX Kconfig option Mike Kravetz
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