From: Alistair Popple <apopple@nvidia.com>
To: Peter Xu <peterx@redhat.com>
Cc: <linux-mm@kvack.org>, <nouveau@lists.freedesktop.org>,
<bskeggs@redhat.com>, <akpm@linux-foundation.org>,
<linux-doc@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<dri-devel@lists.freedesktop.org>, <jhubbard@nvidia.com>,
<rcampbell@nvidia.com>, <jglisse@redhat.com>, <jgg@nvidia.com>,
<hch@infradead.org>, <daniel@ffwll.ch>, <willy@infradead.org>,
<bsingharora@gmail.com>, Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v8 1/8] mm: Remove special swap entry functions
Date: Tue, 18 May 2021 21:58:09 +1000 [thread overview]
Message-ID: <2009782.faHf7sVjGQ@nvdebian> (raw)
In-Reply-To: <YKMjvKGIHdwQN2Ml@t490s>
On Tuesday, 18 May 2021 12:17:32 PM AEST Peter Xu wrote:
> On Wed, Apr 07, 2021 at 06:42:31PM +1000, Alistair Popple wrote:
> > +static inline struct page *pfn_swap_entry_to_page(swp_entry_t entry)
> > +{
> > + struct page *p = pfn_to_page(swp_offset(entry));
> > +
> > + /*
> > + * Any use of migration entries may only occur while the
> > + * corresponding page is locked
> > + */
> > + BUG_ON(is_migration_entry(entry) && !PageLocked(p));
> > +
> > + return p;
> > +}
>
> Would swap_pfn_entry_to_page() be slightly better?
>
> The thing is it's very easy to read pfn_*() as a function to take a pfn as
> parameter...
>
> Since I'm also recently working on some swap-related new ptes [1], I'm
> thinking whether we could name these swap entries as "swap XXX entries".
> Say, "swap hwpoison entry", "swap pfn entry" (which is a superset of "swap
> migration entry", "swap device exclusive entry", ...). That's where I came
> with the above swap_pfn_entry_to_page(), then below will be naturally
> is_swap_pfn_entry().
Equally though "hwpoison swap entry", "pfn swap entry", "migration swap
entry", etc. also makes sense (at least to me), but does that not fit in as
well with your series? I haven't looked too deeply at your series but have
been meaning to so thanks for the pointer.
> No strong opinion as this is already a v8 series (and sorry to chim in this
> late), just to raise this up.
No worries, it's good timing as I was about to send a v9 which was just a
rebase anyway. I am hoping to try and get this accepted for the next merge
window but I will wait before sending v9 to see if anyone else has thoughts on
the naming here.
I don't have a particularly strong opinion either, and your justification is
more thought than I gave to naming these originally so am happy to rename if
it's more readable or fits better with your series.
Thanks.
- Alistair
> [1] https://lore.kernel.org/lkml/20210427161317.50682-1-peterx@redhat.com/
>
> Thanks,
>
> > +
> > +/*
> > + * A pfn swap entry is a special type of swap entry that always has a pfn
> > stored + * in the swap offset. They are used to represent unaddressable
> > device memory + * and to restrict access to a page undergoing migration.
> > + */
> > +static inline bool is_pfn_swap_entry(swp_entry_t entry)
> > +{
> > + return is_migration_entry(entry) || is_device_private_entry(entry);
> > +}
>
> --
> Peter Xu
next prev parent reply other threads:[~2021-05-18 11:58 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-07 8:42 [PATCH v8 0/8] Add support for SVM atomics in Nouveau Alistair Popple
2021-04-07 8:42 ` [PATCH v8 1/8] mm: Remove special swap entry functions Alistair Popple
2021-05-18 2:17 ` Peter Xu
2021-05-18 11:58 ` Alistair Popple [this message]
2021-05-18 14:17 ` Peter Xu
2021-04-07 8:42 ` [PATCH v8 2/8] mm/swapops: Rework swap entry manipulation code Alistair Popple
2021-04-07 8:42 ` [PATCH v8 3/8] mm/rmap: Split try_to_munlock from try_to_unmap Alistair Popple
2021-05-18 20:04 ` Liam Howlett
2021-05-19 12:38 ` Alistair Popple
2021-05-20 20:24 ` Liam Howlett
2021-05-21 2:23 ` Alistair Popple
2021-04-07 8:42 ` [PATCH v8 4/8] mm/rmap: Split migration into its own function Alistair Popple
2021-04-07 8:42 ` [PATCH v8 5/8] mm: Device exclusive memory access Alistair Popple
2021-05-18 2:08 ` Peter Xu
2021-05-18 13:19 ` Alistair Popple
2021-05-18 17:27 ` Peter Xu
2021-05-18 17:33 ` Jason Gunthorpe
2021-05-18 18:01 ` Peter Xu
2021-05-18 19:45 ` Jason Gunthorpe
2021-05-18 20:29 ` Peter Xu
2021-05-18 23:03 ` Jason Gunthorpe
2021-05-18 23:45 ` Peter Xu
2021-05-19 11:04 ` Alistair Popple
2021-05-19 12:15 ` Peter Xu
2021-05-19 13:11 ` Alistair Popple
2021-05-19 14:04 ` Peter Xu
2021-05-19 13:28 ` Jason Gunthorpe
2021-05-19 14:09 ` Peter Xu
2021-05-19 18:11 ` Jason Gunthorpe
2021-05-19 11:35 ` Alistair Popple
2021-05-19 12:21 ` Peter Xu
2021-05-19 12:46 ` Alistair Popple
2021-05-21 6:53 ` Alistair Popple
2021-05-18 21:16 ` Peter Xu
2021-05-19 10:49 ` Alistair Popple
2021-05-19 12:24 ` Peter Xu
2021-05-19 12:46 ` Alistair Popple
2021-04-07 8:42 ` [PATCH v8 6/8] mm: Selftests for exclusive device memory Alistair Popple
2021-04-07 8:42 ` [PATCH v8 7/8] nouveau/svm: Refactor nouveau_range_fault Alistair Popple
2021-04-07 8:42 ` [PATCH v8 8/8] nouveau/svm: Implement atomic SVM access Alistair Popple
2021-05-21 4:04 ` Ben Skeggs
2021-05-06 7:43 ` [PATCH v8 0/8] Add support for SVM atomics in Nouveau Alistair Popple
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