From: Matthew Wilcox <willy@infradead.org>
To: John Hubbard <jhubbard@nvidia.com>
Cc: David Hildenbrand <david@redhat.com>,
Khalid Aziz <khalid.aziz@oracle.com>,
Steven Sistare <steven.sistare@oracle.com>,
akpm@linux-foundation.org, ying.huang@intel.com,
mgorman@techsingularity.net, baolin.wang@linux.alibaba.com,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Khalid Aziz <khalid@kernel.org>
Subject: Re: [PATCH v4] mm, compaction: Skip all non-migratable pages during scan
Date: Sat, 27 May 2023 04:18:07 +0100 [thread overview]
Message-ID: <ZHF2byaRlaX3W6Md@casper.infradead.org> (raw)
In-Reply-To: <846b770c-9f63-90a2-0435-ec82484e3f74@nvidia.com>
On Fri, May 26, 2023 at 07:11:05PM -0700, John Hubbard wrote:
> > So any user with 1024 processes can fragment physical memory? :/
> >
> > Sorry, I'd like to minimize the usage of folio_maybe_dma_pinned().
>
> I was actually thinking that we should minimize any more cases of
> fragile mapcount and refcount comparison, which then leads to
> Matthew's approach here!
I was wondering if we shouldn't make folio_maybe_dma_pinned() a little
more accurate. eg:
if (folio_test_large(folio))
return atomic_read(&folio->_pincount) > 0;
return (unsigned)(folio_ref_count(folio) - folio_mapcount(folio)) >=
GUP_PIN_COUNTING_BIAS;
next prev parent reply other threads:[~2023-05-27 3:18 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-25 19:15 [PATCH v4] mm, compaction: Skip all non-migratable pages during scan Khalid Aziz
2023-05-25 19:58 ` Matthew Wilcox
2023-05-25 20:15 ` Steven Sistare
2023-05-25 20:45 ` Matthew Wilcox
2023-05-25 21:31 ` Matthew Wilcox
2023-05-26 15:44 ` Khalid Aziz
2023-05-26 16:44 ` Matthew Wilcox
2023-05-26 16:46 ` David Hildenbrand
2023-05-26 18:46 ` Matthew Wilcox
2023-05-26 18:50 ` David Hildenbrand
2023-05-27 2:11 ` John Hubbard
2023-05-27 3:18 ` Matthew Wilcox [this message]
2023-05-28 23:49 ` John Hubbard
2023-05-29 0:31 ` Matthew Wilcox
2023-05-29 9:25 ` David Hildenbrand
2023-05-30 15:42 ` Khalid Aziz
2023-06-09 22:11 ` Andrew Morton
2023-06-09 23:28 ` Khalid Aziz
2023-05-25 20:41 ` Khalid Aziz
2023-05-29 3:01 ` Huang, Ying
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