Re: [PATCH v3 2/3] mm: introduce put_user_page*(), placeholder versions
On Fri 05-10-18 19:49:48, john.hubb...@gmail.com wrote: > From: John Hubbard > > Introduces put_user_page(), which simply calls put_page(). > This provides a way to update all get_user_pages*() callers, > so that they call put_user_page(), instead of put_page(). > > Also introduces put_user_pages(), and a few dirty/locked variations, > as a replacement for release_pages(), and also as a replacement > for open-coded loops that release multiple pages. > These may be used for subsequent performance improvements, > via batching of pages to be released. > > This prepares for eventually fixing the problem described > in [1], and is following a plan listed in [2], [3], [4]. > > [1] https://lwn.net/Articles/753027/ : "The Trouble with get_user_pages()" > > [2] https://lkml.kernel.org/r/20180709080554.21931-1-jhubb...@nvidia.com > Proposed steps for fixing get_user_pages() + DMA problems. > > [3]https://lkml.kernel.org/r/20180710082100.mkdwngdv5kkrc...@quack2.suse.cz > Bounce buffers (otherwise [2] is not really viable). > > [4] https://lkml.kernel.org/r/20181003162115.gg24...@quack2.suse.cz > Follow-up discussions. > > CC: Matthew Wilcox > CC: Michal Hocko > CC: Christopher Lameter > CC: Jason Gunthorpe > CC: Dan Williams > CC: Jan Kara > CC: Al Viro > CC: Jerome Glisse > CC: Christoph Hellwig > CC: Ralph Campbell > Signed-off-by: John Hubbard > --- > include/linux/mm.h | 48 -- > 1 file changed, 46 insertions(+), 2 deletions(-) Looks good to me. You can add: Reviewed-by: Jan Kara Just one nit below: > +/* Pages that were pinned via get_user_pages*() should be released via > + * either put_user_page(), or one of the put_user_pages*() routines > + * below. > + */ Multi-line comments usually follow formatting: /* * Some text here * and more text here... */ Honza -- Jan Kara SUSE Labs, CR
Re: [PATCH v3 2/3] mm: introduce put_user_page*(), placeholder versions
On Fri 05-10-18 19:49:48, john.hubb...@gmail.com wrote: > From: John Hubbard > > Introduces put_user_page(), which simply calls put_page(). > This provides a way to update all get_user_pages*() callers, > so that they call put_user_page(), instead of put_page(). > > Also introduces put_user_pages(), and a few dirty/locked variations, > as a replacement for release_pages(), and also as a replacement > for open-coded loops that release multiple pages. > These may be used for subsequent performance improvements, > via batching of pages to be released. > > This prepares for eventually fixing the problem described > in [1], and is following a plan listed in [2], [3], [4]. > > [1] https://lwn.net/Articles/753027/ : "The Trouble with get_user_pages()" > > [2] https://lkml.kernel.org/r/20180709080554.21931-1-jhubb...@nvidia.com > Proposed steps for fixing get_user_pages() + DMA problems. > > [3]https://lkml.kernel.org/r/20180710082100.mkdwngdv5kkrc...@quack2.suse.cz > Bounce buffers (otherwise [2] is not really viable). > > [4] https://lkml.kernel.org/r/20181003162115.gg24...@quack2.suse.cz > Follow-up discussions. > > CC: Matthew Wilcox > CC: Michal Hocko > CC: Christopher Lameter > CC: Jason Gunthorpe > CC: Dan Williams > CC: Jan Kara > CC: Al Viro > CC: Jerome Glisse > CC: Christoph Hellwig > CC: Ralph Campbell > Signed-off-by: John Hubbard > --- > include/linux/mm.h | 48 -- > 1 file changed, 46 insertions(+), 2 deletions(-) Looks good to me. You can add: Reviewed-by: Jan Kara Just one nit below: > +/* Pages that were pinned via get_user_pages*() should be released via > + * either put_user_page(), or one of the put_user_pages*() routines > + * below. > + */ Multi-line comments usually follow formatting: /* * Some text here * and more text here... */ Honza -- Jan Kara SUSE Labs, CR
[PATCH v3 2/3] mm: introduce put_user_page*(), placeholder versions
From: John Hubbard
Introduces put_user_page(), which simply calls put_page().
This provides a way to update all get_user_pages*() callers,
so that they call put_user_page(), instead of put_page().
Also introduces put_user_pages(), and a few dirty/locked variations,
as a replacement for release_pages(), and also as a replacement
for open-coded loops that release multiple pages.
These may be used for subsequent performance improvements,
via batching of pages to be released.
This prepares for eventually fixing the problem described
in [1], and is following a plan listed in [2], [3], [4].
[1] https://lwn.net/Articles/753027/ : "The Trouble with get_user_pages()"
[2] https://lkml.kernel.org/r/20180709080554.21931-1-jhubb...@nvidia.com
Proposed steps for fixing get_user_pages() + DMA problems.
[3]https://lkml.kernel.org/r/20180710082100.mkdwngdv5kkrc...@quack2.suse.cz
Bounce buffers (otherwise [2] is not really viable).
[4] https://lkml.kernel.org/r/20181003162115.gg24...@quack2.suse.cz
Follow-up discussions.
CC: Matthew Wilcox
CC: Michal Hocko
CC: Christopher Lameter
CC: Jason Gunthorpe
CC: Dan Williams
CC: Jan Kara
CC: Al Viro
CC: Jerome Glisse
CC: Christoph Hellwig
CC: Ralph Campbell
Signed-off-by: John Hubbard
---
include/linux/mm.h | 48 --
1 file changed, 46 insertions(+), 2 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 0416a7204be3..305b206e6851 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -137,6 +137,8 @@ extern int overcommit_ratio_handler(struct ctl_table *,
int, void __user *,
size_t *, loff_t *);
extern int overcommit_kbytes_handler(struct ctl_table *, int, void __user *,
size_t *, loff_t *);
+int set_page_dirty(struct page *page);
+int set_page_dirty_lock(struct page *page);
#define nth_page(page,n) pfn_to_page(page_to_pfn((page)) + (n))
@@ -943,6 +945,50 @@ static inline void put_page(struct page *page)
__put_page(page);
}
+/* Pages that were pinned via get_user_pages*() should be released via
+ * either put_user_page(), or one of the put_user_pages*() routines
+ * below.
+ */
+static inline void put_user_page(struct page *page)
+{
+ put_page(page);
+}
+
+static inline void put_user_pages_dirty(struct page **pages,
+ unsigned long npages)
+{
+ unsigned long index;
+
+ for (index = 0; index < npages; index++) {
+ if (!PageDirty(pages[index]))
+ set_page_dirty(pages[index]);
+
+ put_user_page(pages[index]);
+ }
+}
+
+static inline void put_user_pages_dirty_lock(struct page **pages,
+unsigned long npages)
+{
+ unsigned long index;
+
+ for (index = 0; index < npages; index++) {
+ if (!PageDirty(pages[index]))
+ set_page_dirty_lock(pages[index]);
+
+ put_user_page(pages[index]);
+ }
+}
+
+static inline void put_user_pages(struct page **pages,
+ unsigned long npages)
+{
+ unsigned long index;
+
+ for (index = 0; index < npages; index++)
+ put_user_page(pages[index]);
+}
+
#if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
#define SECTION_IN_PAGE_FLAGS
#endif
@@ -1534,8 +1580,6 @@ int redirty_page_for_writepage(struct writeback_control
*wbc,
void account_page_dirtied(struct page *page, struct address_space *mapping);
void account_page_cleaned(struct page *page, struct address_space *mapping,
struct bdi_writeback *wb);
-int set_page_dirty(struct page *page);
-int set_page_dirty_lock(struct page *page);
void __cancel_dirty_page(struct page *page);
static inline void cancel_dirty_page(struct page *page)
{
--
2.19.0
[PATCH v3 2/3] mm: introduce put_user_page*(), placeholder versions
From: John Hubbard
Introduces put_user_page(), which simply calls put_page().
This provides a way to update all get_user_pages*() callers,
so that they call put_user_page(), instead of put_page().
Also introduces put_user_pages(), and a few dirty/locked variations,
as a replacement for release_pages(), and also as a replacement
for open-coded loops that release multiple pages.
These may be used for subsequent performance improvements,
via batching of pages to be released.
This prepares for eventually fixing the problem described
in [1], and is following a plan listed in [2], [3], [4].
[1] https://lwn.net/Articles/753027/ : "The Trouble with get_user_pages()"
[2] https://lkml.kernel.org/r/20180709080554.21931-1-jhubb...@nvidia.com
Proposed steps for fixing get_user_pages() + DMA problems.
[3]https://lkml.kernel.org/r/20180710082100.mkdwngdv5kkrc...@quack2.suse.cz
Bounce buffers (otherwise [2] is not really viable).
[4] https://lkml.kernel.org/r/20181003162115.gg24...@quack2.suse.cz
Follow-up discussions.
CC: Matthew Wilcox
CC: Michal Hocko
CC: Christopher Lameter
CC: Jason Gunthorpe
CC: Dan Williams
CC: Jan Kara
CC: Al Viro
CC: Jerome Glisse
CC: Christoph Hellwig
CC: Ralph Campbell
Signed-off-by: John Hubbard
---
include/linux/mm.h | 48 --
1 file changed, 46 insertions(+), 2 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 0416a7204be3..305b206e6851 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -137,6 +137,8 @@ extern int overcommit_ratio_handler(struct ctl_table *,
int, void __user *,
size_t *, loff_t *);
extern int overcommit_kbytes_handler(struct ctl_table *, int, void __user *,
size_t *, loff_t *);
+int set_page_dirty(struct page *page);
+int set_page_dirty_lock(struct page *page);
#define nth_page(page,n) pfn_to_page(page_to_pfn((page)) + (n))
@@ -943,6 +945,50 @@ static inline void put_page(struct page *page)
__put_page(page);
}
+/* Pages that were pinned via get_user_pages*() should be released via
+ * either put_user_page(), or one of the put_user_pages*() routines
+ * below.
+ */
+static inline void put_user_page(struct page *page)
+{
+ put_page(page);
+}
+
+static inline void put_user_pages_dirty(struct page **pages,
+ unsigned long npages)
+{
+ unsigned long index;
+
+ for (index = 0; index < npages; index++) {
+ if (!PageDirty(pages[index]))
+ set_page_dirty(pages[index]);
+
+ put_user_page(pages[index]);
+ }
+}
+
+static inline void put_user_pages_dirty_lock(struct page **pages,
+unsigned long npages)
+{
+ unsigned long index;
+
+ for (index = 0; index < npages; index++) {
+ if (!PageDirty(pages[index]))
+ set_page_dirty_lock(pages[index]);
+
+ put_user_page(pages[index]);
+ }
+}
+
+static inline void put_user_pages(struct page **pages,
+ unsigned long npages)
+{
+ unsigned long index;
+
+ for (index = 0; index < npages; index++)
+ put_user_page(pages[index]);
+}
+
#if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
#define SECTION_IN_PAGE_FLAGS
#endif
@@ -1534,8 +1580,6 @@ int redirty_page_for_writepage(struct writeback_control
*wbc,
void account_page_dirtied(struct page *page, struct address_space *mapping);
void account_page_cleaned(struct page *page, struct address_space *mapping,
struct bdi_writeback *wb);
-int set_page_dirty(struct page *page);
-int set_page_dirty_lock(struct page *page);
void __cancel_dirty_page(struct page *page);
static inline void cancel_dirty_page(struct page *page)
{
--
2.19.0
