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References: <20230507061726.13422-1-mpenttil@redhat.com> <87wn1ja793.fsf@yhuang6-desk2.ccr.corp.intel.com> Date: Mon, 08 May 2023 13:14:47 +0800 In-Reply-To: ("Mika =?utf-8?Q?Penttil=C3=A4=22's?= message of "Mon, 8 May 2023 05:59:46 +0300") Message-ID: <87sfc79zg8.fsf@yhuang6-desk2.ccr.corp.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 4467B140003 X-Stat-Signature: eh15jdjnt5d5n9oyzmr9kzkmtqyko84g X-Rspam-User: X-Rspamd-Server: rspam09 X-HE-Tag: 1683522987-278698 X-HE-Meta: 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 rwTr8e/D uM6N5ChC0IVn9ziSD+8x0C9DCnKgHOKOEq8k8EIUkgoSb6k2/f1T4+Z3JWmr/cnPG/n4rZBWy7Jv7IBorNbFsjCP4Gh78vh02HoedN+Gf/lt5ekc1BhrNVIbgC0Uy2dvHpB6GWx8TIPwiV0YxxH2T2G3S8+cP1lXt58pSwvpNQuPyVqwYm04qloKWMlAF9Y/XUpn8/Nhs83knJLr7Jm7vifQDGuOq4j0yJNGCbZ4ZCBP3+ayYuXY+U2SMuZ/j4KB6umfqTtKZhf5iQjw= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Mika Penttil=C3=A4 writes: > H, > > > On 8.5.2023 5.26, Huang, Ying wrote: >> mpenttil@redhat.com writes: >>=20 >>> From: Mika Penttil >>> >>> Migrating file pages and swapcache pages into device memory is not supp= orted. >>> 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. >>> >>> As a detail, do not mess with shmem pages, as they handle swap internal= ly. >>> >>> Cc: Alistair Popple >>> Cc: John Hubbard >>> Cc: Ralph Campbell >>> Signed-off-by: Mika Penttil >>> --- >>> mm/migrate_device.c | 12 ++++++++++-- >>> 1 file changed, 10 insertions(+), 2 deletions(-) >>> >>> diff --git a/mm/migrate_device.c b/mm/migrate_device.c >>> index d30c9de60b0d..e8169c58c341 100644 >>> --- a/mm/migrate_device.c >>> +++ b/mm/migrate_device.c >>> @@ -12,6 +12,7 @@ >>> #include >>> #include >>> #include >>> +#include >>> #include >>> #include >>> #include >>> @@ -750,10 +751,17 @@ static void __migrate_device_pages(unsigned long = *src_pfns, >>> /* >>> * For now only support anonymous memory migrating to >>> * device private or coherent memory. >>> + * >>> + * Try to get rid of swap cache if possible. >>> + * Leave shmem pages alone, they handle swap internally >>> + * >>> */ >>> if (mapping) { >>> - src_pfns[i] &=3D ~MIGRATE_PFN_MIGRATE; >>> - continue; >>> + if (shmem_mapping(mapping) || >>> + !folio_free_swap(page_folio(page))) { >> Should we filter out file pages firstly? > > folio_free_swap() checks first and returns false if not swapcache page > (ie including normal file pages) so think that is enough, You are right. folio_free_swap() will call folio_test_swapcache(), and which will check folio_test_swapbacked(). And, IIUC, we don't need to check shmem too. Because folio_free_swap() will not return true for shmem pages. > but maybe for clarity and not depending on it, could be good > explicitly check for swapcache before calling folio_free_swap(). Yes. That will be more clear. I suggest to use folio_test_anon(), that will filter out shmem pages too. >>=20 >>> + src_pfns[i] &=3D ~MIGRATE_PFN_MIGRATE; >>> + continue; >>> + } >>> } >>> } else if (is_zone_device_page(newpage)) { >>> /* Best Regards, Huang, Ying