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From: Muchun Song <muchun.song@linux.dev>
To: Ryan Roberts <ryan.roberts@arm.com>
Cc: "Andrew Morton" <akpm@linux-foundation.org>,
	"SeongJae Park" <sj@kernel.org>,
	"Matthew Wilcox (Oracle)" <willy@infradead.org>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	"Mike Rapoport" <rppt@kernel.org>, "Yu Zhao" <yuzhao@google.com>,
	"Jason Gunthorpe" <jgg@ziepe.ca>,
	"David Airlie" <airlied@gmail.com>,
	"Daniel Vetter" <daniel@ffwll.ch>,
	"Dimitri Sivanich" <dimitri.sivanich@hpe.com>,
	"Alex Williamson" <alex.williamson@redhat.com>,
	"Oleksandr Tyshchenko" <oleksandr_tyshchenko@epam.com>,
	"Alexander Viro" <viro@zeniv.linux.org.uk>,
	"Christian Brauner" <brauner@kernel.org>,
	"Mike Kravetz" <mike.kravetz@oracle.com>,
	"Mark Rutland" <mark.rutland@arm.com>,
	"Alexander Shishkin" <alexander.shishkin@linux.intel.com>,
	"Jiri Olsa" <jolsa@kernel.org>,
	"Namhyung Kim" <namhyung@kernel.org>,
	"Ian Rogers" <irogers@google.com>,
	"Adrian Hunter" <adrian.hunter@intel.com>,
	"Jérôme Glisse" <jglisse@redhat.com>,
	"Andrey Ryabinin" <ryabinin.a.a@gmail.com>,
	"Alexander Potapenko" <glider@google.com>,
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	"Dmitry Vyukov" <dvyukov@google.com>,
	"Vincenzo Frascino" <vincenzo.frascino@arm.com>,
	"Johannes Weiner" <hannes@cmpxchg.org>,
	"Michal Hocko" <mhocko@kernel.org>,
	"Roman Gushchin" <roman.gushchin@linux.dev>,
	"Shakeel Butt" <shakeelb@google.com>,
	"Naoya Horiguchi" <naoya.horiguchi@nec.com>,
	"Miaohe Lin" <linmiaohe@huawei.com>,
	"Pasha Tatashin" <pasha.tatashin@soleen.com>,
	"Uladzislau Rezki" <urezki@gmail.com>,
	"Christoph Hellwig" <hch@infradead.org>,
	"Lorenzo Stoakes" <lstoakes@gmail.com>,
	linux-kernel@vger.kernel.org,
	"Linux Memory Management List" <linux-mm@kvack.org>,
	damon@lists.linux.dev
Subject: Re: [PATCH v3 0/3] Encapsulate PTE contents from non-arch code
Date: Tue, 13 Jun 2023 10:16:26 +0800	[thread overview]
Message-ID: <3ECE40AA-536E-4A2C-82BA-FE74AA6FB689@linux.dev> (raw)
In-Reply-To: <20230612151545.3317766-1-ryan.roberts@arm.com>



> On Jun 12, 2023, at 23:15, Ryan Roberts <ryan.roberts@arm.com> wrote:
> 
> Hi All,
> 
> (Including wider audience this time since changes touch a fair few subsystems)
> 
> This is the second half of v3 of a series to improve the encapsulation of pte
> entries by disallowing non-arch code from directly dereferencing pte_t pointers.
> Based on earlier feedback, I split the series in 2; the first part, fixes for
> existing bugs, was already posted at [3] and merged into mm-stable. This second
> part contains the conversion from direct dereferences to instead use
> ptep_get()/ptep_get_lockless().
> 
> See the v1 cover letter at [1] for rationale for this work.
> 
> Based on feedback at v2, I've removed the new ptep_deref() helper I originally
> added, and am now using the existing ptep_get() and ptep_get_lockless() helpers.

When I first saw the name of ptep_get()/ptep_get_lockless(), I thought
the pte seems like to be protected by the refcount mechanism (Why I have
this though? Because Qi Zheng has proposed a approach to free pte page tables
by using the refcount mechanism [1]). And your proposed name of ptep_deref()
is intuitive for me, so I have another thought, should we rename ptep_get()
to ptep_deref()? Just a thought from me, I'd like to hear if others object.

Thanks.

[1] https://lore.kernel.org/lkml/20211110105428.32458-7-zhengqi.arch@bytedance.com/

  parent reply	other threads:[~2023-06-13  2:17 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-06-12 15:15 Ryan Roberts
2023-06-12 15:15 ` [PATCH v3 1/3] mm: ptdump should use ptep_get_lockless() Ryan Roberts
2023-06-12 15:15 ` [PATCH v3 2/3] mm: Move ptep_get() and pmdp_get() helpers Ryan Roberts
2023-06-12 15:15 ` [PATCH v3 3/3] mm: ptep_get() conversion Ryan Roberts
2023-06-12 21:27   ` SeongJae Park
2023-06-12 20:16 ` [PATCH v3 0/3] Encapsulate PTE contents from non-arch code Andrew Morton
2023-06-13  8:43   ` Ryan Roberts
2023-06-13  2:16 ` Muchun Song [this message]
2023-06-13  8:52   ` Ryan Roberts

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