From: David Miller <davem@davemloft.net>
To: mike.kravetz@oracle.com
Cc: sparclinux@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, bob.picco@oracle.com,
nitin.m.gupta@oracle.com, vijay.ac.kumar@oracle.com,
julian.calaby@gmail.com, adam.buchbinder@gmail.com,
kirill.shutemov@linux.intel.com, mhocko@suse.com,
akpm@linux-foundation.org
Subject: Re: [RFC PATCH 05/14] sparc64: Add PAGE_SHR_CTX flag
Date: Tue, 20 Dec 2016 13:33:59 -0500 (EST) [thread overview]
Message-ID: <20161220.133359.577475873353753419.davem@davemloft.net> (raw)
In-Reply-To: <0311a0ea-097b-be27-3f4d-14bbba46348c@oracle.com>
From: Mike Kravetz <mike.kravetz@oracle.com>
Date: Sun, 18 Dec 2016 16:42:52 -0800
> On 12/17/2016 07:12 PM, David Miller wrote:
>> From: Mike Kravetz <mike.kravetz@oracle.com>
>> Date: Fri, 16 Dec 2016 10:35:28 -0800
>>
>>> @@ -166,6 +166,7 @@ bool kern_addr_valid(unsigned long addr);
>>> #define _PAGE_EXEC_4V _AC(0x0000000000000080,UL) /* Executable Page */
>>> #define _PAGE_W_4V _AC(0x0000000000000040,UL) /* Writable */
>>> #define _PAGE_SOFT_4V _AC(0x0000000000000030,UL) /* Software bits */
>>> +#define _PAGE_SHR_CTX_4V _AC(0x0000000000000020,UL) /* Shared Context */
>>> #define _PAGE_PRESENT_4V _AC(0x0000000000000010,UL) /* Present */
>>> #define _PAGE_RESV_4V _AC(0x0000000000000008,UL) /* Reserved */
>>> #define _PAGE_SZ16GB_4V _AC(0x0000000000000007,UL) /* 16GB Page */
>>
>> You really don't need this.
>>
>> The VMA is available, and you can obtain the information you need
>> about whether this is a shared mapping or not from the. It just isn't
>> being passed down into things like set_huge_pte_at(). Simply make it
>> do so.
>>
>
> I was more concerned about the page table walk code at tlb/tsb miss time.
> Specifically, the code after tsb_miss_page_table_walk_sun4v_fastpath in
> tsb.S. AFAICT, the tsb entries should have been created when the pte entries
> were created. Yet, this code is still walking the page table and creating
> tsb entries. We do not have a pointer to the vma here, and I thought it
> would be somewhat difficult to get access. This is the reason why I went
> down the path of a page flag.
You are right, you will need a page flag for that part.
next prev parent reply other threads:[~2016-12-20 18:34 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
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 [this message]
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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