From: Matthew Wilcox <willy@infradead.org>
To: Ira Weiny <ira.weiny@intel.com>
Cc: "Fabio M. De Francesco"
<fabio.maria.de.francesco@linux.intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm/memory: Replace kmap() with kmap_local_page()
Date: Wed, 20 Dec 2023 19:59:13 +0000 [thread overview]
Message-ID: <ZYNHkQZhwvM81TZP@casper.infradead.org> (raw)
In-Reply-To: <6583463e8de5c_30a94294fb@iweiny-mobl.notmuch>
On Wed, Dec 20, 2023 at 11:53:34AM -0800, Ira Weiny wrote:
> > My understanding of the current implementation is that unmap_and_put_page()
> > calls folio_release_kmap(), taking as arguments the folio which the page
> > belongs to and the kernel virtual address returned by kmap_local_page().
> >
> > folio_release_kmap() calls kunmap_local() and then folio_put(). The last is
> > called on the folio obtained by the unmap_and_put_page() wrapper and, if I'm
> > not wrong, it releases refcounts on folios like put_page() does on pages.
>
> This is where my consternation came from. I saw the folio_put() and did
> not realize that get_page() now calls folio_get().
That's not new. See 86d234cb0499 which changed get_page() to call
folio_get(), but notice that it's doing the _exact same thing_ that
get_page() used to do. And it's behaved this way since ddc58f27f9ee
in 2016.
next prev parent reply other threads:[~2023-12-20 19:59 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-15 8:43 [PATCH] mm/memory: Replace kmap() with kmap_local_page() Fabio M. De Francesco
2023-12-18 3:34 ` Ira Weiny
2023-12-18 7:43 ` Fabio M. De Francesco
2023-12-20 19:53 ` Ira Weiny
2023-12-20 19:59 ` Matthew Wilcox [this message]
-- strict thread matches above, loose matches on Subject: below --
2023-12-14 8:10 Fabio M. De Francesco
2023-12-14 19:47 ` Andrew Morton
2023-12-15 8:40 ` Fabio M. De Francesco
2023-12-15 16:17 ` Fabio M. De Francesco
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