From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1752960AbcLSAwh (ORCPT <rfc822;w@1wt.eu>);
        Sun, 18 Dec 2016 19:52:37 -0500
Received: from userp1040.oracle.com ([156.151.31.81]:37322 "EHLO
        userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1752549AbcLSAwg (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Sun, 18 Dec 2016 19:52:36 -0500
Subject: Re: [RFC PATCH 06/14] sparc64: general shared context tsb creation
 and support
To: Sam Ravnborg <sam@ravnborg.org>
References: <1481913337-9331-1-git-send-email-mike.kravetz@oracle.com>
 <1481913337-9331-7-git-send-email-mike.kravetz@oracle.com>
 <20161217075325.GD23567@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>
From: Mike Kravetz <mike.kravetz@oracle.com>
Message-ID: <6f8647b9-76eb-1b02-ab68-40509b2163fe@oracle.com>
Date: Sun, 18 Dec 2016 16:52:18 -0800
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101
 Thunderbird/45.5.1
MIME-Version: 1.0
In-Reply-To: <20161217075325.GD23567@ravnborg.org>
Content-Type: text/plain; charset=windows-1252
Content-Transfer-Encoding: 7bit
X-Source-IP: userv0022.oracle.com [156.151.31.74]
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On 12/16/2016 11:53 PM, Sam Ravnborg wrote:
> Hi Mike
> 
>> --- a/arch/sparc/mm/hugetlbpage.c
>> +++ b/arch/sparc/mm/hugetlbpage.c
>> @@ -162,8 +162,14 @@ void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
>>  {
>>  	pte_t orig;
>>  
>> -	if (!pte_present(*ptep) && pte_present(entry))
>> -		mm->context.hugetlb_pte_count++;
>> +	if (!pte_present(*ptep) && pte_present(entry)) {
>> +#if defined(CONFIG_SHARED_MMU_CTX)
>> +		if (pte_val(entry) | _PAGE_SHR_CTX_4V)
>> +			mm->context.shared_hugetlb_pte_count++;
>> +		else
>> +#endif
>> +			mm->context.hugetlb_pte_count++;
>> +	}
> 
> This kind of conditional code it just too ugly to survive...
> Could a static inline be used to help you here?
> The compiler will inline it so there should not be any run-time cost

Yes, this can be cleaned up in that way.

> 
>>  
>>  	mm_rss -= saved_thp_pte_count * (HPAGE_SIZE / PAGE_SIZE);
>>  #endif
>> @@ -544,8 +576,10 @@ int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
>>  	 * us, so we need to zero out the TSB pointer or else tsb_grow()
>>  	 * will be confused and think there is an older TSB to free up.
>>  	 */
>> -	for (i = 0; i < MM_NUM_TSBS; i++)
>> +	for (i = 0; i < MM_NUM_TSBS; i++) {
>>  		mm->context.tsb_block[i].tsb = NULL;
>> +		mm->context.tsb_descr[i].tsb_base = 0UL;
>> +	}
> This change seems un-related to the rest?

Correct.  I was experimenting with some other ways of managing the tsb_descr
array that got dropped, but forgot to remove this.

-- 
Mike Kravetz

> 
> 	Sam
>