From: Alistair Popple <apopple@nvidia.com>
To: linux-mm@kvack.org, akpm@linux-foundation.org
Cc: 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>,
Matthew Wilcox <willy@infradead.org>,
Alistair Popple <apopple@nvidia.com>
Subject: [PATCH v4 1/2] mm/gup.c: Don't pass gup_flags to check_and_migrate_movable_pages()
Date: Fri, 12 Aug 2022 12:13:08 +1000 [thread overview]
Message-ID: <487960bf67c7273ff5606c76f73bb51271bc7b90.1660269441.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>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
---
Changes for v3:
- Move WARN_ON() out of loop
---
mm/gup.c | 23 ++++++++++-------------
1 file changed, 10 insertions(+), 13 deletions(-)
diff --git a/mm/gup.c b/mm/gup.c
index c6d060d..a2baa8b 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;
}
@@ -2047,13 +2040,17 @@ static long __gup_longterm_locked(struct mm_struct *mm,
if (!(gup_flags & FOLL_LONGTERM))
return __get_user_pages_locked(mm, start, nr_pages, pages, vmas,
NULL, gup_flags);
+ /* check_and_migrate_movable_pages() assumes pages have been pinned. */
+ if (WARN_ON(!(gup_flags & FOLL_PIN)))
+ return -EINVAL;
flags = memalloc_pin_save();
do {
rc = __get_user_pages_locked(mm, start, nr_pages, pages, vmas,
NULL, gup_flags);
if (rc <= 0)
break;
- rc = check_and_migrate_movable_pages(rc, pages, gup_flags);
+
+ 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:[~2022-08-12 2:13 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-12 2:13 Alistair Popple [this message]
2022-08-12 2:13 ` [PATCH v4 2/2] mm/gup.c: Refactor check_and_migrate_movable_pages() Alistair Popple
2022-08-12 7:05 ` John Hubbard
2022-08-15 16:15 ` Jason Gunthorpe
2022-08-16 5:29 ` Alistair Popple
2022-08-16 11:29 ` Jason Gunthorpe
2022-08-17 2:01 ` Alistair Popple
2022-08-17 12:09 ` Jason Gunthorpe
2022-08-17 20:35 ` John Hubbard
2022-08-17 22:50 ` Jason Gunthorpe
2022-08-17 23:05 ` John Hubbard
2022-08-17 23:24 ` Alistair Popple
2022-08-17 23:40 ` Jason Gunthorpe
2022-08-12 12:57 ` [PATCH v4 1/2] mm/gup.c: Don't pass gup_flags to check_and_migrate_movable_pages() Matthew Wilcox
2022-08-12 18:02 ` John Hubbard
2022-08-12 18:11 ` Matthew Wilcox
2022-08-15 5:52 ` Alistair Popple
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