From: Alistair Popple <apopple@nvidia.com>
To: linux-mm@kvack.org
Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
"Sierra Guiza, Alejandro (Alex)" <alex.sierra@amd.com>,
Chaitanya Kulkarni <kch@nvidia.com>,
Dan Williams <dan.j.williams@intel.com>,
Felix Kuehling <Felix.Kuehling@amd.com>,
Jason Gunthorpe <jgg@nvidia.com>,
John Hubbard <jhubbard@nvidia.com>,
Logan Gunthorpe <logang@deltatee.com>,
Miaohe Lin <linmiaohe@huawei.com>,
Muchun Song <songmuchun@bytedance.com>,
Ralph Campbell <rcampbell@nvidia.com>,
David Hildenbrand <david@redhat.com>,
Alistair Popple <apopple@nvidia.com>
Subject: [PATCH v2 1/2] mm/gup.c: Don't pass gup_flags to check_and_migrate_movable_pages()
Date: Fri, 5 Aug 2022 16:29:52 +1000 [thread overview]
Message-ID: <3e20a542e756bbc0f66435c9344ff674f3ff7ac7.1659680600.git-series.apopple@nvidia.com> (raw)
gup_flags is passed to check_and_migrate_movable_pages() so that it can
call either put_page() or unpin_user_page() to drop the page reference.
However check_and_migrate_movable_pages() is only called for
FOLL_LONGTERM, which implies FOLL_PIN so there is no need to pass
gup_flags.
Signed-off-by: Alistair Popple <apopple@nvidia.com>
---
mm/gup.c | 21 ++++++++-------------
1 file changed, 8 insertions(+), 13 deletions(-)
diff --git a/mm/gup.c b/mm/gup.c
index c6d060d..e26ccc0 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1907,8 +1907,7 @@ struct page *get_dump_page(unsigned long addr)
* Return negative error if migration fails.
*/
static long check_and_migrate_movable_pages(unsigned long nr_pages,
- struct page **pages,
- unsigned int gup_flags)
+ struct page **pages)
{
unsigned long isolation_error_count = 0, i;
struct folio *prev_folio = NULL;
@@ -1941,10 +1940,8 @@ static long check_and_migrate_movable_pages(unsigned long nr_pages,
* Migration will fail if the page is pinned, so convert
* the pin on the source page to a normal reference.
*/
- if (gup_flags & FOLL_PIN) {
- get_page(&folio->page);
- unpin_user_page(&folio->page);
- }
+ get_page(&folio->page);
+ unpin_user_page(&folio->page);
ret = migrate_device_coherent_page(&folio->page);
if (ret)
@@ -1998,10 +1995,7 @@ static long check_and_migrate_movable_pages(unsigned long nr_pages,
if (!pages[i])
continue;
- if (gup_flags & FOLL_PIN)
- unpin_user_page(pages[i]);
- else
- put_page(pages[i]);
+ unpin_user_page(pages[i]);
}
if (!list_empty(&movable_page_list)) {
@@ -2023,8 +2017,7 @@ static long check_and_migrate_movable_pages(unsigned long nr_pages,
}
#else
static long check_and_migrate_movable_pages(unsigned long nr_pages,
- struct page **pages,
- unsigned int gup_flags)
+ struct page **pages)
{
return nr_pages;
}
@@ -2053,7 +2046,9 @@ static long __gup_longterm_locked(struct mm_struct *mm,
NULL, gup_flags);
if (rc <= 0)
break;
- rc = check_and_migrate_movable_pages(rc, pages, gup_flags);
+
+ WARN_ON_ONCE(!(gup_flags & FOLL_PIN));
+ rc = check_and_migrate_movable_pages(rc, pages);
} while (!rc);
memalloc_pin_restore(flags);
base-commit: 360614c01f81f48a89d8b13f8fa69c3ae0a1f5c7
--
git-series 0.9.1
next reply other threads:[~2022-08-05 6:30 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-05 6:29 Alistair Popple [this message]
2022-08-05 6:29 ` [PATCH v2 2/2] mm/gup.c: Refactor check_and_migrate_movable_pages() Alistair Popple
2022-08-05 8:12 ` David Hildenbrand
2022-08-05 8:15 ` John Hubbard
2022-08-08 1:38 ` Alistair Popple
2022-08-05 7:35 ` [PATCH v2 1/2] mm/gup.c: Don't pass gup_flags to check_and_migrate_movable_pages() John Hubbard
2022-08-05 8:10 ` David Hildenbrand
2022-08-05 12:06 ` Jason Gunthorpe
2022-08-08 1:55 ` Alistair Popple
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