linux-kernel - Re: [Linux-kernel-mentees][PATCH v4 1/1] sgi-gru: Remove *pte

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Message-ID: <20190809094451.GB22457@bharath12345-Inspiron-5559>
Date:   Fri, 9 Aug 2019 15:14:51 +0530
From:   Bharath Vedartham <linux.bhar@...il.com>
To:     John Hubbard <jhubbard@...dia.com>
Cc:     arnd@...db.de, gregkh@...uxfoundation.org, sivanich@....com,
        ira.weiny@...el.com, jglisse@...hat.com,
        william.kucharski@...cle.com, hch@....de,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        linux-kernel-mentees@...ts.linuxfoundation.org
Subject: Re: [Linux-kernel-mentees][PATCH v4 1/1] sgi-gru: Remove *pte_lookup
 functions

On Thu, Aug 08, 2019 at 04:30:48PM -0700, John Hubbard wrote:
> On 8/8/19 4:21 PM, John Hubbard wrote:
> > On 8/8/19 11:55 AM, Bharath Vedartham wrote:
> > ...
> >>  	if (is_gru_paddr(paddr))
> >>  		goto inval;
> >> -	paddr = paddr & ~((1UL << ps) - 1);
> >> +	paddr = paddr & ~((1UL << *pageshift) - 1);
> >>  	*gpa = uv_soc_phys_ram_to_gpa(paddr);
> >> -	*pageshift = ps;
> > 
> > Why are you no longer setting *pageshift? There are a couple of callers
> > that both use this variable.
> > 
> > 
> 
> ...and once that's figured out, I can fix it up here and send it up with 
> the next misc callsites series. I'm also inclined to make the commit
> log read more like this:
> 
> sgi-gru: Remove *pte_lookup functions, convert to put_user_page*()
> 
> For pages that were retained via get_user_pages*(), release those pages
> via the new put_user_page*() routines, instead of via put_page() or
> release_pages().
> 
> This is part a tree-wide conversion, as described in commit fc1d8e7cca2d
> ("mm: introduce put_user_page*(), placeholder versions").
> 
> As part of this conversion, the *pte_lookup functions can be removed and
> be easily replaced with get_user_pages_fast() functions. In the case of
> atomic lookup, __get_user_pages_fast() is used, because it does not fall
> back to the slow path: get_user_pages(). get_user_pages_fast(), on the other
> hand, first calls __get_user_pages_fast(), but then falls back to the
> slow path if __get_user_pages_fast() fails.
> 
> Also: remove unnecessary CONFIG_HUGETLB ifdefs.
Sounds great! I will send the next version with an updated changelog!

Thank you
Bharath
> 
> thanks,
> -- 
> John Hubbard
> NVIDIA