From: Matthew Wilcox <willy@infradead.org>
To: Ryan Roberts <ryan.roberts@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Yin Fengwei <fengwei.yin@intel.com>,
David Hildenbrand <david@redhat.com>, Yu Zhao <yuzhao@google.com>,
Yang Shi <shy828301@gmail.com>,
"Huang, Ying" <ying.huang@intel.com>, Zi Yan <ziy@nvidia.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH v1 2/3] mm: Implement folio_remove_rmap_range()
Date: Mon, 17 Jul 2023 16:56:41 +0100 [thread overview]
Message-ID: <ZLVkucGl88vxEuIu@casper.infradead.org> (raw)
In-Reply-To: <adac1493-da6d-4581-b8b1-e5911b68cdd7@arm.com>
On Mon, Jul 17, 2023 at 04:49:19PM +0100, Ryan Roberts wrote:
> > We're still doing one atomic op per page on the folio's nr_pages_mapped
> > ... is it possible to batch this and use atomic_sub_return_relaxed()?
>
> Good spot, something like this:
>
> } else {
> for (; nr != 0; nr--, page++) {
> /* Is this the page's last map to be removed? */
> last = atomic_add_negative(-1, &page->_mapcount);
> if (last)
> nr_unmapped++;
> }
>
> /* Pages still mapped if folio mapped entirely */
> nr_mapped = atomic_sub_return_relaxed(nr_unmapped, mapped);
> if (nr_mapped >= COMPOUND_MAPPED)
> nr_unmapped = 0;
> }
I think that's right, but my eyes always go slightly crossed trying to
read the new mapcount scheme.
next prev parent reply other threads:[~2023-07-17 15:56 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-17 14:31 [PATCH v1 0/3] Optimize large folio interaction with deferred split Ryan Roberts
2023-07-17 14:31 ` [PATCH v1 1/3] mm: Allow deferred splitting of arbitrary large anon folios Ryan Roberts
2023-07-17 15:30 ` Matthew Wilcox
2023-07-17 15:41 ` Ryan Roberts
2023-07-17 15:43 ` David Hildenbrand
2023-07-17 15:54 ` Matthew Wilcox
2023-07-17 16:17 ` Matthew Wilcox
2023-07-17 16:55 ` David Hildenbrand
2023-07-17 15:42 ` David Hildenbrand
2023-07-17 16:01 ` Ryan Roberts
2023-07-17 16:48 ` David Hildenbrand
2023-07-18 8:58 ` Ryan Roberts
2023-07-18 9:08 ` David Hildenbrand
2023-07-18 9:33 ` Ryan Roberts
2023-07-17 14:31 ` [PATCH v1 2/3] mm: Implement folio_remove_rmap_range() Ryan Roberts
2023-07-17 15:07 ` Matthew Wilcox
2023-07-17 15:49 ` Ryan Roberts
2023-07-17 15:56 ` Matthew Wilcox [this message]
2023-07-17 15:09 ` Zi Yan
2023-07-17 15:51 ` Ryan Roberts
2023-07-17 15:53 ` Zi Yan
2023-07-18 1:14 ` Yin Fengwei
2023-07-18 6:22 ` Huang, Ying
2023-07-18 9:51 ` Ryan Roberts
2023-07-18 7:12 ` Huang, Ying
2023-07-18 10:02 ` Ryan Roberts
2023-07-17 14:31 ` [PATCH v1 3/3] mm: Batch-zap large anonymous folio PTE mappings Ryan Roberts
2023-07-17 15:25 ` Zi Yan
2023-07-17 15:55 ` Ryan Roberts
2023-07-17 16:15 ` Zi Yan
2023-07-18 10:19 ` Ryan Roberts
2023-07-18 14:01 ` Zi Yan
2023-07-17 23:27 ` Yin Fengwei
2023-07-18 10:27 ` Ryan Roberts
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