| Message ID | 20231106061541.507116-2-vivek.kasireddy@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mm/gup: Introduce pin_user_pages_fd() for pinning shmem/hugetlbfs file pages (v2) | expand |
On Sun, Nov 05, 2023 at 10:15:39PM -0800, Vivek Kasireddy wrote: > For drivers that would like to longterm-pin the pages associated > with a file, the pin_user_pages_fd() API provides an option to > not only pin the pages via FOLL_PIN but also to check and migrate > them if they reside in movable zone or CMA block. This API > currently works with files that belong to either shmem or hugetlbfs. > Files belonging to other filesystems are rejected for now. > > The pages need to be located first before pinning them via FOLL_PIN. > If they are found in the page cache, they can be immediately pinned. > Otherwise, they need to be allocated using the filesystem specific > APIs and then pinned. > > v2: > - Drop gup_flags and improve comments and commit message (David) > - Allocate a page if we cannot find in page cache for the hugetlbfs > case as well (David) > - Don't unpin pages if there is a migration related failure (David) > - Drop the unnecessary nr_pages <= 0 check (Jason) > - Have the caller of the API pass in file * instead of fd (Jason) > > Cc: David Hildenbrand <david@redhat.com> > Cc: Daniel Vetter <daniel.vetter@ffwll.ch> > Cc: Mike Kravetz <mike.kravetz@oracle.com> > Cc: Hugh Dickins <hughd@google.com> > Cc: Peter Xu <peterx@redhat.com> > Cc: Gerd Hoffmann <kraxel@redhat.com> > Cc: Dongwon Kim <dongwon.kim@intel.com> > Cc: Junxiao Chang <junxiao.chang@intel.com> > Suggested-by: Jason Gunthorpe <jgg@nvidia.com> > Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com> > --- > include/linux/mm.h | 2 + > mm/gup.c | 99 ++++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 101 insertions(+) Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Jason
Hi Vivek,
kernel test robot noticed the following build errors:
[auto build test ERROR on akpm-mm/mm-everything]
url: https://github.com/intel-lab-lkp/linux/commits/Vivek-Kasireddy/mm-gup-Introduce-pin_user_pages_fd-for-pinning-shmem-hugetlbfs-file-pages-v2/20231106-141954
base: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link: https://lore.kernel.org/r/20231106061541.507116-2-vivek.kasireddy%40intel.com
patch subject: [PATCH v2 1/3] mm/gup: Introduce pin_user_pages_fd() for pinning shmem/hugetlbfs file pages (v2)
config: um-allyesconfig (https://download.01.org/0day-ci/archive/20231107/202311071110.ZGF6P4zc-lkp@intel.com/config)
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project.git f28c006a5895fc0e329fe15fead81e37457cb1d1)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231107/202311071110.ZGF6P4zc-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202311071110.ZGF6P4zc-lkp@intel.com/
All errors (new ones prefixed by >>):
In file included from mm/gup.c:9:
In file included from include/linux/pagemap.h:11:
In file included from include/linux/highmem.h:12:
In file included from include/linux/hardirq.h:11:
In file included from arch/um/include/asm/hardirq.h:5:
In file included from include/asm-generic/hardirq.h:17:
In file included from include/linux/irq.h:20:
In file included from include/linux/io.h:13:
In file included from arch/um/include/asm/io.h:24:
include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
val = __raw_readb(PCI_IOBASE + addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
~~~~~~~~~~ ^
include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu'
#define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
^
In file included from mm/gup.c:9:
In file included from include/linux/pagemap.h:11:
In file included from include/linux/highmem.h:12:
In file included from include/linux/hardirq.h:11:
In file included from arch/um/include/asm/hardirq.h:5:
In file included from include/asm-generic/hardirq.h:17:
In file included from include/linux/irq.h:20:
In file included from include/linux/io.h:13:
In file included from arch/um/include/asm/io.h:24:
include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
~~~~~~~~~~ ^
include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu'
#define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
^
In file included from mm/gup.c:9:
In file included from include/linux/pagemap.h:11:
In file included from include/linux/highmem.h:12:
In file included from include/linux/hardirq.h:11:
In file included from arch/um/include/asm/hardirq.h:5:
In file included from include/asm-generic/hardirq.h:17:
In file included from include/linux/irq.h:20:
In file included from include/linux/io.h:13:
In file included from arch/um/include/asm/io.h:24:
include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
__raw_writeb(value, PCI_IOBASE + addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
__raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
__raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:692:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
readsb(PCI_IOBASE + addr, buffer, count);
~~~~~~~~~~ ^
include/asm-generic/io.h:700:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
readsw(PCI_IOBASE + addr, buffer, count);
~~~~~~~~~~ ^
include/asm-generic/io.h:708:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
readsl(PCI_IOBASE + addr, buffer, count);
~~~~~~~~~~ ^
include/asm-generic/io.h:717:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
writesb(PCI_IOBASE + addr, buffer, count);
~~~~~~~~~~ ^
include/asm-generic/io.h:726:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
writesw(PCI_IOBASE + addr, buffer, count);
~~~~~~~~~~ ^
include/asm-generic/io.h:735:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
writesl(PCI_IOBASE + addr, buffer, count);
~~~~~~~~~~ ^
>> mm/gup.c:3419:9: error: implicit declaration of function 'hugetlb_add_to_page_cache' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
err = hugetlb_add_to_page_cache(folio, file->f_mapping, idx);
^
12 warnings and 1 error generated.
vim +/hugetlb_add_to_page_cache +3419 mm/gup.c
3403
3404 static struct page *alloc_file_page(struct file *file, pgoff_t idx)
3405 {
3406 struct page *page = ERR_PTR(-ENOMEM);
3407 struct folio *folio;
3408 int err;
3409
3410 if (shmem_file(file))
3411 return shmem_read_mapping_page(file->f_mapping, idx);
3412
3413 folio = alloc_hugetlb_folio_nodemask(hstate_file(file),
3414 NUMA_NO_NODE,
3415 NULL,
3416 GFP_USER);
3417 if (folio && folio_try_get(folio)) {
3418 page = &folio->page;
> 3419 err = hugetlb_add_to_page_cache(folio, file->f_mapping, idx);
3420 if (err) {
3421 folio_put(folio);
3422 free_huge_folio(folio);
3423 page = ERR_PTR(err);
3424 }
3425 }
3426
3427 return page;
3428 }
3429
Hi Vivek, kernel test robot noticed the following build errors: [auto build test ERROR on akpm-mm/mm-everything] url: https://github.com/intel-lab-lkp/linux/commits/Vivek-Kasireddy/mm-gup-Introduce-pin_user_pages_fd-for-pinning-shmem-hugetlbfs-file-pages-v2/20231106-141954 base: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything patch link: https://lore.kernel.org/r/20231106061541.507116-2-vivek.kasireddy%40intel.com patch subject: [PATCH v2 1/3] mm/gup: Introduce pin_user_pages_fd() for pinning shmem/hugetlbfs file pages (v2) config: mips-maltaup_defconfig (https://download.01.org/0day-ci/archive/20231107/202311071223.ZeoRZg33-lkp@intel.com/config) compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project.git 4a5ac14ee968ff0ad5d2cc1ffa0299048db4c88a) reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231107/202311071223.ZeoRZg33-lkp@intel.com/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <lkp@intel.com> | Closes: https://lore.kernel.org/oe-kbuild-all/202311071223.ZeoRZg33-lkp@intel.com/ All errors (new ones prefixed by >>): >> mm/gup.c:3419:9: error: call to undeclared function 'hugetlb_add_to_page_cache'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] 3419 | err = hugetlb_add_to_page_cache(folio, file->f_mapping, idx); | ^ 1 error generated. vim +/hugetlb_add_to_page_cache +3419 mm/gup.c 3403 3404 static struct page *alloc_file_page(struct file *file, pgoff_t idx) 3405 { 3406 struct page *page = ERR_PTR(-ENOMEM); 3407 struct folio *folio; 3408 int err; 3409 3410 if (shmem_file(file)) 3411 return shmem_read_mapping_page(file->f_mapping, idx); 3412 3413 folio = alloc_hugetlb_folio_nodemask(hstate_file(file), 3414 NUMA_NO_NODE, 3415 NULL, 3416 GFP_USER); 3417 if (folio && folio_try_get(folio)) { 3418 page = &folio->page; > 3419 err = hugetlb_add_to_page_cache(folio, file->f_mapping, idx); 3420 if (err) { 3421 folio_put(folio); 3422 free_huge_folio(folio); 3423 page = ERR_PTR(err); 3424 } 3425 } 3426 3427 return page; 3428 } 3429
On 06.11.23 07:15, Vivek Kasireddy wrote: > For drivers that would like to longterm-pin the pages associated > with a file, the pin_user_pages_fd() API provides an option to > not only pin the pages via FOLL_PIN but also to check and migrate > them if they reside in movable zone or CMA block. This API > currently works with files that belong to either shmem or hugetlbfs. > Files belonging to other filesystems are rejected for now. > > The pages need to be located first before pinning them via FOLL_PIN. > If they are found in the page cache, they can be immediately pinned. > Otherwise, they need to be allocated using the filesystem specific > APIs and then pinned. > > v2: > - Drop gup_flags and improve comments and commit message (David) > - Allocate a page if we cannot find in page cache for the hugetlbfs > case as well (David) > - Don't unpin pages if there is a migration related failure (David) > - Drop the unnecessary nr_pages <= 0 check (Jason) > - Have the caller of the API pass in file * instead of fd (Jason) > > Cc: David Hildenbrand <david@redhat.com> > Cc: Daniel Vetter <daniel.vetter@ffwll.ch> > Cc: Mike Kravetz <mike.kravetz@oracle.com> > Cc: Hugh Dickins <hughd@google.com> > Cc: Peter Xu <peterx@redhat.com> > Cc: Gerd Hoffmann <kraxel@redhat.com> > Cc: Dongwon Kim <dongwon.kim@intel.com> > Cc: Junxiao Chang <junxiao.chang@intel.com> > Suggested-by: Jason Gunthorpe <jgg@nvidia.com> > Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com> > --- > include/linux/mm.h | 2 + > mm/gup.c | 99 ++++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 101 insertions(+) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index bf5d0b1b16f4..f6cc17b14653 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -2457,6 +2457,8 @@ long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages, > struct page **pages, unsigned int gup_flags); > long pin_user_pages_unlocked(unsigned long start, unsigned long nr_pages, > struct page **pages, unsigned int gup_flags); > +long pin_user_pages_fd(struct file *file, pgoff_t start, > + unsigned long nr_pages, struct page **pages); > > int get_user_pages_fast(unsigned long start, int nr_pages, > unsigned int gup_flags, struct page **pages); > diff --git a/mm/gup.c b/mm/gup.c > index 2f8a2d89fde1..d30b9dfebbb6 100644 > --- a/mm/gup.c > +++ b/mm/gup.c > @@ -3400,3 +3400,102 @@ long pin_user_pages_unlocked(unsigned long start, unsigned long nr_pages, > &locked, gup_flags); > } > EXPORT_SYMBOL(pin_user_pages_unlocked); > + > +static struct page *alloc_file_page(struct file *file, pgoff_t idx) > +{ > + struct page *page = ERR_PTR(-ENOMEM); > + struct folio *folio; > + int err; > + > + if (shmem_file(file)) > + return shmem_read_mapping_page(file->f_mapping, idx); > + As the build reports indicate, this might have to be fenced with #ifdef CONFIG_HUGETLB_PAGE > + folio = alloc_hugetlb_folio_nodemask(hstate_file(file), > + NUMA_NO_NODE, > + NULL, > + GFP_USER); > + if (folio && folio_try_get(folio)) { > + page = &folio->page; > + err = hugetlb_add_to_page_cache(folio, file->f_mapping, idx); > + if (err) { > + folio_put(folio); > + free_huge_folio(folio); > + page = ERR_PTR(err); > + } > + } > + > + return page; > +} > + > +/** > + * pin_user_pages_fd() - pin user pages associated with a file > + * @file: the file whose pages are to be pinned > + * @start: starting file offset > + * @nr_pages: number of pages from start to pin > + * @pages: array that receives pointers to the pages pinned. > + * Should be at-least nr_pages long. > + * > + * Attempt to pin pages associated with a file that belongs to either shmem > + * or hugetlbfs. The pages are either found in the page cache or allocated nit: s/hugetlbfs/hugetlb/ > + * if necessary. Once the pages are located, they are all pinned via FOLL_PIN. > + * And, these pinned pages need to be released using unpin_user_pages() or > + * unpin_user_page(). > + * It might be reasonable to add that the behavior mimics FOLL_LONGTERM semantics: the page may be held for an indefinite time period _often_ under userspace control. > + * Returns number of pages pinned. This would be equal to the number of > + * pages requested. If no pages were pinned, it returns -errno. > + */ > +long pin_user_pages_fd(struct file *file, pgoff_t start, > + unsigned long nr_pages, struct page **pages) > +{ > + struct page *page; > + unsigned int flags, i; > + long ret; > + > + if (start < 0) > + return -EINVAL; > + > + if (!file) > + return -EINVAL; > + > + if (!shmem_file(file) && !is_file_hugepages(file)) > + return -EINVAL; > + > + flags = memalloc_pin_save(); > + do { > + for (i = 0; i < nr_pages; i++) { > + /* > + * In most cases, we should be able to find the page > + * in the page cache. If we cannot find it, we try to > + * allocate one and add it to the page cache. > + */ > + page = find_get_page_flags(file->f_mapping, > + start + i, > + FGP_ACCESSED); > + if (!page) { > + page = alloc_file_page(file, start + i); > + if (IS_ERR(page)) { > + ret = PTR_ERR(page); > + goto err; > + } > + } > + ret = try_grab_page(page, FOLL_PIN); > + if (unlikely(ret)) > + goto err; > + > + pages[i] = page; > + put_page(pages[i]); > + } > + > + ret = check_and_migrate_movable_pages(nr_pages, pages); > + } while (ret == -EAGAIN); > + > + memalloc_pin_restore(flags); > + return ret ? ret : nr_pages; > +err: missing memalloc_pin_restore() ? > + while (i > 0 && pages[--i]) > + unpin_user_page(pages[i]); So if any pages[] would be 0, we would stop completely? Shouldn't this be something like: while (i-- > 0) if (pages[i]) unpin_user_page(pages[i]);
diff --git a/include/linux/mm.h b/include/linux/mm.h index bf5d0b1b16f4..f6cc17b14653 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2457,6 +2457,8 @@ long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages, struct page **pages, unsigned int gup_flags); long pin_user_pages_unlocked(unsigned long start, unsigned long nr_pages, struct page **pages, unsigned int gup_flags); +long pin_user_pages_fd(struct file *file, pgoff_t start, + unsigned long nr_pages, struct page **pages); int get_user_pages_fast(unsigned long start, int nr_pages, unsigned int gup_flags, struct page **pages); diff --git a/mm/gup.c b/mm/gup.c index 2f8a2d89fde1..d30b9dfebbb6 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -3400,3 +3400,102 @@ long pin_user_pages_unlocked(unsigned long start, unsigned long nr_pages, &locked, gup_flags); } EXPORT_SYMBOL(pin_user_pages_unlocked); + +static struct page *alloc_file_page(struct file *file, pgoff_t idx) +{ + struct page *page = ERR_PTR(-ENOMEM); + struct folio *folio; + int err; + + if (shmem_file(file)) + return shmem_read_mapping_page(file->f_mapping, idx); + + folio = alloc_hugetlb_folio_nodemask(hstate_file(file), + NUMA_NO_NODE, + NULL, + GFP_USER); + if (folio && folio_try_get(folio)) { + page = &folio->page; + err = hugetlb_add_to_page_cache(folio, file->f_mapping, idx); + if (err) { + folio_put(folio); + free_huge_folio(folio); + page = ERR_PTR(err); + } + } + + return page; +} + +/** + * pin_user_pages_fd() - pin user pages associated with a file + * @file: the file whose pages are to be pinned + * @start: starting file offset + * @nr_pages: number of pages from start to pin + * @pages: array that receives pointers to the pages pinned. + * Should be at-least nr_pages long. + * + * Attempt to pin pages associated with a file that belongs to either shmem + * or hugetlbfs. The pages are either found in the page cache or allocated + * if necessary. Once the pages are located, they are all pinned via FOLL_PIN. + * And, these pinned pages need to be released using unpin_user_pages() or + * unpin_user_page(). + * + * Returns number of pages pinned. This would be equal to the number of + * pages requested. If no pages were pinned, it returns -errno. + */ +long pin_user_pages_fd(struct file *file, pgoff_t start, + unsigned long nr_pages, struct page **pages) +{ + struct page *page; + unsigned int flags, i; + long ret; + + if (start < 0) + return -EINVAL; + + if (!file) + return -EINVAL; + + if (!shmem_file(file) && !is_file_hugepages(file)) + return -EINVAL; + + flags = memalloc_pin_save(); + do { + for (i = 0; i < nr_pages; i++) { + /* + * In most cases, we should be able to find the page + * in the page cache. If we cannot find it, we try to + * allocate one and add it to the page cache. + */ + page = find_get_page_flags(file->f_mapping, + start + i, + FGP_ACCESSED); + if (!page) { + page = alloc_file_page(file, start + i); + if (IS_ERR(page)) { + ret = PTR_ERR(page); + goto err; + } + } + ret = try_grab_page(page, FOLL_PIN); + if (unlikely(ret)) + goto err; + + pages[i] = page; + put_page(pages[i]); + } + + ret = check_and_migrate_movable_pages(nr_pages, pages); + } while (ret == -EAGAIN); + + memalloc_pin_restore(flags); + return ret ? ret : nr_pages; +err: + while (i > 0 && pages[--i]) + unpin_user_page(pages[i]); + + return ret; +} +EXPORT_SYMBOL_GPL(pin_user_pages_fd); +
For drivers that would like to longterm-pin the pages associated with a file, the pin_user_pages_fd() API provides an option to not only pin the pages via FOLL_PIN but also to check and migrate them if they reside in movable zone or CMA block. This API currently works with files that belong to either shmem or hugetlbfs. Files belonging to other filesystems are rejected for now. The pages need to be located first before pinning them via FOLL_PIN. If they are found in the page cache, they can be immediately pinned. Otherwise, they need to be allocated using the filesystem specific APIs and then pinned. v2: - Drop gup_flags and improve comments and commit message (David) - Allocate a page if we cannot find in page cache for the hugetlbfs case as well (David) - Don't unpin pages if there is a migration related failure (David) - Drop the unnecessary nr_pages <= 0 check (Jason) - Have the caller of the API pass in file * instead of fd (Jason) Cc: David Hildenbrand <david@redhat.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Hugh Dickins <hughd@google.com> Cc: Peter Xu <peterx@redhat.com> Cc: Gerd Hoffmann <kraxel@redhat.com> Cc: Dongwon Kim <dongwon.kim@intel.com> Cc: Junxiao Chang <junxiao.chang@intel.com> Suggested-by: Jason Gunthorpe <jgg@nvidia.com> Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com> --- include/linux/mm.h | 2 + mm/gup.c | 99 ++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 101 insertions(+)