linux-kernel - Re: [PATCH v12 09/33] mm: Add folio_try_get

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Message-ID: <20210628123849.4gok3kf43wyjp2ix@box.shutemov.name>
Date:   Mon, 28 Jun 2021 15:38:49 +0300
From:   "Kirill A. Shutemov" <kirill@...temov.name>
To:     "Matthew Wilcox (Oracle)" <willy@...radead.org>
Cc:     akpm@...ux-foundation.org, linux-fsdevel@...r.kernel.org,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        Vlastimil Babka <vbabka@...e.cz>,
        William Kucharski <william.kucharski@...cle.com>,
        Christoph Hellwig <hch@....de>
Subject: Re: [PATCH v12 09/33] mm: Add folio_try_get_rcu()

On Tue, Jun 22, 2021 at 12:40:54PM +0100, Matthew Wilcox (Oracle) wrote:
> This is the equivalent of page_cache_get_speculative().  Also add
> folio_ref_try_add_rcu (the equivalent of page_cache_add_speculative)
> and folio_get_unless_zero() (the equivalent of get_page_unless_zero()).
> 
> The new kernel-doc attempts to explain from the user's point of view
> when to use folio_try_get_rcu() and when to use folio_get_unless_zero(),
> because there seems to be some confusion currently between the users of
> page_cache_get_speculative() and get_page_unless_zero().
> 
> Reimplement page_cache_add_speculative() and page_cache_get_speculative()
> as wrappers around the folio equivalents, but leave get_page_unless_zero()
> alone for now.  This commit reduces text size by 3 bytes due to slightly
> different register allocation & instruction selections.
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@...radead.org>
> Acked-by: Vlastimil Babka <vbabka@...e.cz>
> Reviewed-by: William Kucharski <william.kucharski@...cle.com>
> Reviewed-by: Christoph Hellwig <hch@....de>

Acked-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>

-- 
 Kirill A. Shutemov