From: "Huang, Ying" <ying.huang@intel.com>
To: mpenttil@redhat.com
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Alistair Popple <apopple@nvidia.com>,
John Hubbard <jhubbard@nvidia.com>,
Ralph Campbell <rcampbell@nvidia.com>
Subject: Re: [PATCH v2] mm/migrate_device: Try to handle swapcache pages
Date: Wed, 31 May 2023 15:24:32 +0800 [thread overview]
Message-ID: <87wn0pt13j.fsf@yhuang6-desk2.ccr.corp.intel.com> (raw)
In-Reply-To: <20230531044018.17893-1-mpenttil@redhat.com> (mpenttil@redhat.com's message of "Wed, 31 May 2023 07:40:18 +0300")
mpenttil@redhat.com writes:
> From: Mika Penttilä <mpenttil@redhat.com>
>
> Migrating file pages and swapcache pages into device memory is not supported.
> The decision is done based on page_mapping(). For now, swapcache pages are not migrated.
>
> Things can however be improved, for swapcache pages. Try to get rid of the swap cache,
> and if successful, go ahead as with other anonymous pages.
>
> Cc: Alistair Popple <apopple@nvidia.com>
> Cc: John Hubbard <jhubbard@nvidia.com>
> Cc: Ralph Campbell <rcampbell@nvidia.com>
> Cc: Huang Ying <ying.huang@intel.com>
> Signed-off-by: Mika Penttilä <mpenttil@redhat.com>
> ---
>
> v2:
> - use folio_test_anon() (Huang, Ying)
>
>
> mm/migrate_device.c | 24 ++++++++++++++++++------
> 1 file changed, 18 insertions(+), 6 deletions(-)
>
> diff --git a/mm/migrate_device.c b/mm/migrate_device.c
> index d30c9de60b0d..829bbc526758 100644
> --- a/mm/migrate_device.c
> +++ b/mm/migrate_device.c
> @@ -747,13 +747,25 @@ static void __migrate_device_pages(unsigned long *src_pfns,
>
> if (is_device_private_page(newpage) ||
> is_device_coherent_page(newpage)) {
> - /*
> - * For now only support anonymous memory migrating to
> - * device private or coherent memory.
> - */
> +
> if (mapping) {
> - src_pfns[i] &= ~MIGRATE_PFN_MIGRATE;
> - continue;
> + struct folio *folio;
> +
> + folio = page_folio(page);
> +
> + /*
> + * For now only support anonymous memory migrating to
> + * device private or coherent memory.
> + *
> + * Try to get rid of swap cache if possible.
I think we can delete the following 2 lines of comments. They add
nothing except what code says already.
Otherwise looks good to me.
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
> + * page is here file or swapcache page, could be shmem also
> + * folio_test_anon() filters out file and shmem
> + *
> + */
> + if (!folio_test_anon(folio) || !folio_free_swap(folio)) {
> + src_pfns[i] &= ~MIGRATE_PFN_MIGRATE;
> + continue;
> + }
> }
> } else if (is_zone_device_page(newpage)) {
> /*
prev parent reply other threads:[~2023-05-31 7:25 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-31 4:40 [PATCH v2] mm/migrate_device: Try to handle swapcache pages mpenttil
2023-05-31 7:24 ` Huang, Ying [this message]
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