[PATCH 9/9] [media] mm: Move get_vaddr_frames() behind a config option
Jan Kara
jack at suse.cz
Thu Jun 18 06:44:49 PDT 2015
On Wed 10-06-15 09:37:20, Josh Triplett wrote:
> On Wed, Jun 10, 2015 at 06:20:52AM -0300, Mauro Carvalho Chehab wrote:
> > From: Jan Kara <jack at suse.cz>
> >
> > get_vaddr_frames() is used by relatively rare drivers so hide it and the
> > related functions behind a config option that is selected only by
> > drivers that need the infrastructure.
> >
> > Suggested-by: Andrew Morton <akpm at linux-foundation.org>
> >
> > Signed-off-by: Jan Kara <jack at suse.cz>
> > Signed-off-by: Hans Verkuil <hans.verkuil at cisco.com>
> > Signed-off-by: Mauro Carvalho Chehab <mchehab at osg.samsung.com>
>
> Seems sensible to me.
>
> Since this patch makes the kernel smaller, can you include the delta
> from bloat-o-meter between allnoconfig with and without this patch?
The results are:
add/remove: 0/6 grow/shrink: 0/0 up/down: 0/-868 (-868)
function old new delta
frame_vector_destroy 55 - -55
frame_vector_to_pfns 56 - -56
frame_vector_create 81 - -81
put_vaddr_frames 93 - -93
frame_vector_to_pages 98 - -98
get_vaddr_frames 485 - -485
I've added it to the changelog of the patch.
> Also, I assume you've compile-tested the kernel with allyesconfig minus
> the three options that now have "select FRAME_VECTOR", to make sure it
> builds?
I did not because the config option VIDEOBUF2_MEMOPS is a virtual one
selected transitively by quite a few video drivers and I didn't bother with
tracking down all of them... But since that config option guards
compilation of the code I modified I'm pretty confident I got it right.
Honza
> > create mode 100644 mm/frame_vector.c
> >
> > diff --git a/drivers/gpu/drm/exynos/Kconfig b/drivers/gpu/drm/exynos/Kconfig
> > index 0a6780367d28..fc678289cf79 100644
> > --- a/drivers/gpu/drm/exynos/Kconfig
> > +++ b/drivers/gpu/drm/exynos/Kconfig
> > @@ -71,6 +71,7 @@ config DRM_EXYNOS_VIDI
> > config DRM_EXYNOS_G2D
> > bool "Exynos DRM G2D"
> > depends on DRM_EXYNOS && !VIDEO_SAMSUNG_S5P_G2D
> > + select FRAME_VECTOR
> > help
> > Choose this option if you want to use Exynos G2D for DRM.
> >
> > diff --git a/drivers/media/platform/omap/Kconfig b/drivers/media/platform/omap/Kconfig
> > index dc2aaab54aef..217d613b0fe7 100644
> > --- a/drivers/media/platform/omap/Kconfig
> > +++ b/drivers/media/platform/omap/Kconfig
> > @@ -10,6 +10,7 @@ config VIDEO_OMAP2_VOUT
> > select OMAP2_DSS if HAS_IOMEM && ARCH_OMAP2PLUS
> > select OMAP2_VRFB if ARCH_OMAP2 || ARCH_OMAP3
> > select VIDEO_OMAP2_VOUT_VRFB if VIDEO_OMAP2_VOUT && OMAP2_VRFB
> > + select FRAME_VECTOR
> > default n
> > ---help---
> > V4L2 Display driver support for OMAP2/3 based boards.
> > diff --git a/drivers/media/v4l2-core/Kconfig b/drivers/media/v4l2-core/Kconfig
> > index f7a01a72eb9e..f38f6e387f04 100644
> > --- a/drivers/media/v4l2-core/Kconfig
> > +++ b/drivers/media/v4l2-core/Kconfig
> > @@ -73,6 +73,7 @@ config VIDEOBUF2_CORE
> >
> > config VIDEOBUF2_MEMOPS
> > tristate
> > + select FRAME_VECTOR
> >
> > config VIDEOBUF2_DMA_CONTIG
> > tristate
> > diff --git a/mm/Kconfig b/mm/Kconfig
> > index 390214da4546..2ca52e9986f0 100644
> > --- a/mm/Kconfig
> > +++ b/mm/Kconfig
> > @@ -635,3 +635,6 @@ config MAX_STACK_SIZE_MB
> > changed to a smaller value in which case that is used.
> >
> > A sane initial value is 80 MB.
> > +
> > +config FRAME_VECTOR
> > + bool
> > diff --git a/mm/Makefile b/mm/Makefile
> > index 98c4eaeabdcb..be5d5c866305 100644
> > --- a/mm/Makefile
> > +++ b/mm/Makefile
> > @@ -78,3 +78,4 @@ obj-$(CONFIG_CMA) += cma.o
> > obj-$(CONFIG_MEMORY_BALLOON) += balloon_compaction.o
> > obj-$(CONFIG_PAGE_EXTENSION) += page_ext.o
> > obj-$(CONFIG_CMA_DEBUGFS) += cma_debug.o
> > +obj-$(CONFIG_FRAME_VECTOR) += frame_vector.o
> > diff --git a/mm/frame_vector.c b/mm/frame_vector.c
> > new file mode 100644
> > index 000000000000..31a2bd5f41d5
> > --- /dev/null
> > +++ b/mm/frame_vector.c
> > @@ -0,0 +1,232 @@
> > +#include <linux/kernel.h>
> > +#include <linux/errno.h>
> > +#include <linux/err.h>
> > +#include <linux/mm.h>
> > +#include <linux/slab.h>
> > +#include <linux/pagemap.h>
> > +#include <linux/sched.h>
> > +
> > +/*
> > + * get_vaddr_frames() - map virtual addresses to pfns
> > + * @start: starting user address
> > + * @nr_frames: number of pages / pfns from start to map
> > + * @write: whether pages will be written to by the caller
> > + * @force: whether to force write access even if user mapping is
> > + * readonly. See description of the same argument of
> > + get_user_pages().
> > + * @vec: structure which receives pages / pfns of the addresses mapped.
> > + * It should have space for at least nr_frames entries.
> > + *
> > + * This function maps virtual addresses from @start and fills @vec structure
> > + * with page frame numbers or page pointers to corresponding pages (choice
> > + * depends on the type of the vma underlying the virtual address). If @start
> > + * belongs to a normal vma, the function grabs reference to each of the pages
> > + * to pin them in memory. If @start belongs to VM_IO | VM_PFNMAP vma, we don't
> > + * touch page structures and the caller must make sure pfns aren't reused for
> > + * anything else while he is using them.
> > + *
> > + * The function returns number of pages mapped which may be less than
> > + * @nr_frames. In particular we stop mapping if there are more vmas of
> > + * different type underlying the specified range of virtual addresses.
> > + * When the function isn't able to map a single page, it returns error.
> > + *
> > + * This function takes care of grabbing mmap_sem as necessary.
> > + */
> > +int get_vaddr_frames(unsigned long start, unsigned int nr_frames,
> > + bool write, bool force, struct frame_vector *vec)
> > +{
> > + struct mm_struct *mm = current->mm;
> > + struct vm_area_struct *vma;
> > + int ret = 0;
> > + int err;
> > + int locked;
> > +
> > + if (nr_frames == 0)
> > + return 0;
> > +
> > + if (WARN_ON_ONCE(nr_frames > vec->nr_allocated))
> > + nr_frames = vec->nr_allocated;
> > +
> > + down_read(&mm->mmap_sem);
> > + locked = 1;
> > + vma = find_vma_intersection(mm, start, start + 1);
> > + if (!vma) {
> > + ret = -EFAULT;
> > + goto out;
> > + }
> > + if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) {
> > + vec->got_ref = true;
> > + vec->is_pfns = false;
> > + ret = get_user_pages_locked(current, mm, start, nr_frames,
> > + write, force, (struct page **)(vec->ptrs), &locked);
> > + goto out;
> > + }
> > +
> > + vec->got_ref = false;
> > + vec->is_pfns = true;
> > + do {
> > + unsigned long *nums = frame_vector_pfns(vec);
> > +
> > + while (ret < nr_frames && start + PAGE_SIZE <= vma->vm_end) {
> > + err = follow_pfn(vma, start, &nums[ret]);
> > + if (err) {
> > + if (ret == 0)
> > + ret = err;
> > + goto out;
> > + }
> > + start += PAGE_SIZE;
> > + ret++;
> > + }
> > + /*
> > + * We stop if we have enough pages or if VMA doesn't completely
> > + * cover the tail page.
> > + */
> > + if (ret >= nr_frames || start < vma->vm_end)
> > + break;
> > + vma = find_vma_intersection(mm, start, start + 1);
> > + } while (vma && vma->vm_flags & (VM_IO | VM_PFNMAP));
> > +out:
> > + if (locked)
> > + up_read(&mm->mmap_sem);
> > + if (!ret)
> > + ret = -EFAULT;
> > + if (ret > 0)
> > + vec->nr_frames = ret;
> > + return ret;
> > +}
> > +EXPORT_SYMBOL(get_vaddr_frames);
> > +
> > +/**
> > + * put_vaddr_frames() - drop references to pages if get_vaddr_frames() acquired
> > + * them
> > + * @vec: frame vector to put
> > + *
> > + * Drop references to pages if get_vaddr_frames() acquired them. We also
> > + * invalidate the frame vector so that it is prepared for the next call into
> > + * get_vaddr_frames().
> > + */
> > +void put_vaddr_frames(struct frame_vector *vec)
> > +{
> > + int i;
> > + struct page **pages;
> > +
> > + if (!vec->got_ref)
> > + goto out;
> > + pages = frame_vector_pages(vec);
> > + /*
> > + * frame_vector_pages() might needed to do a conversion when
> > + * get_vaddr_frames() got pages but vec was later converted to pfns.
> > + * But it shouldn't really fail to convert pfns back...
> > + */
> > + if (WARN_ON(IS_ERR(pages)))
> > + goto out;
> > + for (i = 0; i < vec->nr_frames; i++)
> > + put_page(pages[i]);
> > + vec->got_ref = false;
> > +out:
> > + vec->nr_frames = 0;
> > +}
> > +EXPORT_SYMBOL(put_vaddr_frames);
> > +
> > +/**
> > + * frame_vector_to_pages - convert frame vector to contain page pointers
> > + * @vec: frame vector to convert
> > + *
> > + * Convert @vec to contain array of page pointers. If the conversion is
> > + * successful, return 0. Otherwise return an error. Note that we do not grab
> > + * page references for the page structures.
> > + */
> > +int frame_vector_to_pages(struct frame_vector *vec)
> > +{
> > + int i;
> > + unsigned long *nums;
> > + struct page **pages;
> > +
> > + if (!vec->is_pfns)
> > + return 0;
> > + nums = frame_vector_pfns(vec);
> > + for (i = 0; i < vec->nr_frames; i++)
> > + if (!pfn_valid(nums[i]))
> > + return -EINVAL;
> > + pages = (struct page **)nums;
> > + for (i = 0; i < vec->nr_frames; i++)
> > + pages[i] = pfn_to_page(nums[i]);
> > + vec->is_pfns = false;
> > + return 0;
> > +}
> > +EXPORT_SYMBOL(frame_vector_to_pages);
> > +
> > +/**
> > + * frame_vector_to_pfns - convert frame vector to contain pfns
> > + * @vec: frame vector to convert
> > + *
> > + * Convert @vec to contain array of pfns.
> > + */
> > +void frame_vector_to_pfns(struct frame_vector *vec)
> > +{
> > + int i;
> > + unsigned long *nums;
> > + struct page **pages;
> > +
> > + if (vec->is_pfns)
> > + return;
> > + pages = (struct page **)(vec->ptrs);
> > + nums = (unsigned long *)pages;
> > + for (i = 0; i < vec->nr_frames; i++)
> > + nums[i] = page_to_pfn(pages[i]);
> > + vec->is_pfns = true;
> > +}
> > +EXPORT_SYMBOL(frame_vector_to_pfns);
> > +
> > +/**
> > + * frame_vector_create() - allocate & initialize structure for pinned pfns
> > + * @nr_frames: number of pfns slots we should reserve
> > + *
> > + * Allocate and initialize struct pinned_pfns to be able to hold @nr_pfns
> > + * pfns.
> > + */
> > +struct frame_vector *frame_vector_create(unsigned int nr_frames)
> > +{
> > + struct frame_vector *vec;
> > + int size = sizeof(struct frame_vector) + sizeof(void *) * nr_frames;
> > +
> > + if (WARN_ON_ONCE(nr_frames == 0))
> > + return NULL;
> > + /*
> > + * This is absurdly high. It's here just to avoid strange effects when
> > + * arithmetics overflows.
> > + */
> > + if (WARN_ON_ONCE(nr_frames > INT_MAX / sizeof(void *) / 2))
> > + return NULL;
> > + /*
> > + * Avoid higher order allocations, use vmalloc instead. It should
> > + * be rare anyway.
> > + */
> > + if (size <= PAGE_SIZE)
> > + vec = kmalloc(size, GFP_KERNEL);
> > + else
> > + vec = vmalloc(size);
> > + if (!vec)
> > + return NULL;
> > + vec->nr_allocated = nr_frames;
> > + vec->nr_frames = 0;
> > + return vec;
> > +}
> > +EXPORT_SYMBOL(frame_vector_create);
> > +
> > +/**
> > + * frame_vector_destroy() - free memory allocated to carry frame vector
> > + * @vec: Frame vector to free
> > + *
> > + * Free structure allocated by frame_vector_create() to carry frames.
> > + */
> > +void frame_vector_destroy(struct frame_vector *vec)
> > +{
> > + /* Make sure put_vaddr_frames() got called properly... */
> > + VM_BUG_ON(vec->nr_frames > 0);
> > + if (!is_vmalloc_addr(vec))
> > + kfree(vec);
> > + else
> > + vfree(vec);
> > +}
> > +EXPORT_SYMBOL(frame_vector_destroy);
> > diff --git a/mm/gup.c b/mm/gup.c
> > index 9d7f4fde30cb..222d57e335f9 100644
> > --- a/mm/gup.c
> > +++ b/mm/gup.c
> > @@ -937,231 +937,6 @@ int __mm_populate(unsigned long start, unsigned long len, int ignore_errors)
> > return ret; /* 0 or negative error code */
> > }
> >
> > -/*
> > - * get_vaddr_frames() - map virtual addresses to pfns
> > - * @start: starting user address
> > - * @nr_frames: number of pages / pfns from start to map
> > - * @write: whether pages will be written to by the caller
> > - * @force: whether to force write access even if user mapping is
> > - * readonly. See description of the same argument of
> > - get_user_pages().
> > - * @vec: structure which receives pages / pfns of the addresses mapped.
> > - * It should have space for at least nr_frames entries.
> > - *
> > - * This function maps virtual addresses from @start and fills @vec structure
> > - * with page frame numbers or page pointers to corresponding pages (choice
> > - * depends on the type of the vma underlying the virtual address). If @start
> > - * belongs to a normal vma, the function grabs reference to each of the pages
> > - * to pin them in memory. If @start belongs to VM_IO | VM_PFNMAP vma, we don't
> > - * touch page structures and the caller must make sure pfns aren't reused for
> > - * anything else while he is using them.
> > - *
> > - * The function returns number of pages mapped which may be less than
> > - * @nr_frames. In particular we stop mapping if there are more vmas of
> > - * different type underlying the specified range of virtual addresses.
> > - * When the function isn't able to map a single page, it returns error.
> > - *
> > - * This function takes care of grabbing mmap_sem as necessary.
> > - */
> > -int get_vaddr_frames(unsigned long start, unsigned int nr_frames,
> > - bool write, bool force, struct frame_vector *vec)
> > -{
> > - struct mm_struct *mm = current->mm;
> > - struct vm_area_struct *vma;
> > - int ret = 0;
> > - int err;
> > - int locked;
> > -
> > - if (nr_frames == 0)
> > - return 0;
> > -
> > - if (WARN_ON_ONCE(nr_frames > vec->nr_allocated))
> > - nr_frames = vec->nr_allocated;
> > -
> > - down_read(&mm->mmap_sem);
> > - locked = 1;
> > - vma = find_vma_intersection(mm, start, start + 1);
> > - if (!vma) {
> > - ret = -EFAULT;
> > - goto out;
> > - }
> > - if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) {
> > - vec->got_ref = true;
> > - vec->is_pfns = false;
> > - ret = get_user_pages_locked(current, mm, start, nr_frames,
> > - write, force, (struct page **)(vec->ptrs), &locked);
> > - goto out;
> > - }
> > -
> > - vec->got_ref = false;
> > - vec->is_pfns = true;
> > - do {
> > - unsigned long *nums = frame_vector_pfns(vec);
> > -
> > - while (ret < nr_frames && start + PAGE_SIZE <= vma->vm_end) {
> > - err = follow_pfn(vma, start, &nums[ret]);
> > - if (err) {
> > - if (ret == 0)
> > - ret = err;
> > - goto out;
> > - }
> > - start += PAGE_SIZE;
> > - ret++;
> > - }
> > - /*
> > - * We stop if we have enough pages or if VMA doesn't completely
> > - * cover the tail page.
> > - */
> > - if (ret >= nr_frames || start < vma->vm_end)
> > - break;
> > - vma = find_vma_intersection(mm, start, start + 1);
> > - } while (vma && vma->vm_flags & (VM_IO | VM_PFNMAP));
> > -out:
> > - if (locked)
> > - up_read(&mm->mmap_sem);
> > - if (!ret)
> > - ret = -EFAULT;
> > - if (ret > 0)
> > - vec->nr_frames = ret;
> > - return ret;
> > -}
> > -EXPORT_SYMBOL(get_vaddr_frames);
> > -
> > -/**
> > - * put_vaddr_frames() - drop references to pages if get_vaddr_frames() acquired
> > - * them
> > - * @vec: frame vector to put
> > - *
> > - * Drop references to pages if get_vaddr_frames() acquired them. We also
> > - * invalidate the frame vector so that it is prepared for the next call into
> > - * get_vaddr_frames().
> > - */
> > -void put_vaddr_frames(struct frame_vector *vec)
> > -{
> > - int i;
> > - struct page **pages;
> > -
> > - if (!vec->got_ref)
> > - goto out;
> > - pages = frame_vector_pages(vec);
> > - /*
> > - * frame_vector_pages() might needed to do a conversion when
> > - * get_vaddr_frames() got pages but vec was later converted to pfns.
> > - * But it shouldn't really fail to convert pfns back...
> > - */
> > - if (WARN_ON(IS_ERR(pages)))
> > - goto out;
> > - for (i = 0; i < vec->nr_frames; i++)
> > - put_page(pages[i]);
> > - vec->got_ref = false;
> > -out:
> > - vec->nr_frames = 0;
> > -}
> > -EXPORT_SYMBOL(put_vaddr_frames);
> > -
> > -/**
> > - * frame_vector_to_pages - convert frame vector to contain page pointers
> > - * @vec: frame vector to convert
> > - *
> > - * Convert @vec to contain array of page pointers. If the conversion is
> > - * successful, return 0. Otherwise return an error. Note that we do not grab
> > - * page references for the page structures.
> > - */
> > -int frame_vector_to_pages(struct frame_vector *vec)
> > -{
> > - int i;
> > - unsigned long *nums;
> > - struct page **pages;
> > -
> > - if (!vec->is_pfns)
> > - return 0;
> > - nums = frame_vector_pfns(vec);
> > - for (i = 0; i < vec->nr_frames; i++)
> > - if (!pfn_valid(nums[i]))
> > - return -EINVAL;
> > - pages = (struct page **)nums;
> > - for (i = 0; i < vec->nr_frames; i++)
> > - pages[i] = pfn_to_page(nums[i]);
> > - vec->is_pfns = false;
> > - return 0;
> > -}
> > -EXPORT_SYMBOL(frame_vector_to_pages);
> > -
> > -/**
> > - * frame_vector_to_pfns - convert frame vector to contain pfns
> > - * @vec: frame vector to convert
> > - *
> > - * Convert @vec to contain array of pfns.
> > - */
> > -void frame_vector_to_pfns(struct frame_vector *vec)
> > -{
> > - int i;
> > - unsigned long *nums;
> > - struct page **pages;
> > -
> > - if (vec->is_pfns)
> > - return;
> > - pages = (struct page **)(vec->ptrs);
> > - nums = (unsigned long *)pages;
> > - for (i = 0; i < vec->nr_frames; i++)
> > - nums[i] = page_to_pfn(pages[i]);
> > - vec->is_pfns = true;
> > -}
> > -EXPORT_SYMBOL(frame_vector_to_pfns);
> > -
> > -/**
> > - * frame_vector_create() - allocate & initialize structure for pinned pfns
> > - * @nr_frames: number of pfns slots we should reserve
> > - *
> > - * Allocate and initialize struct pinned_pfns to be able to hold @nr_pfns
> > - * pfns.
> > - */
> > -struct frame_vector *frame_vector_create(unsigned int nr_frames)
> > -{
> > - struct frame_vector *vec;
> > - int size = sizeof(struct frame_vector) + sizeof(void *) * nr_frames;
> > -
> > - if (WARN_ON_ONCE(nr_frames == 0))
> > - return NULL;
> > - /*
> > - * This is absurdly high. It's here just to avoid strange effects when
> > - * arithmetics overflows.
> > - */
> > - if (WARN_ON_ONCE(nr_frames > INT_MAX / sizeof(void *) / 2))
> > - return NULL;
> > - /*
> > - * Avoid higher order allocations, use vmalloc instead. It should
> > - * be rare anyway.
> > - */
> > - if (size <= PAGE_SIZE)
> > - vec = kmalloc(size, GFP_KERNEL);
> > - else
> > - vec = vmalloc(size);
> > - if (!vec)
> > - return NULL;
> > - vec->nr_allocated = nr_frames;
> > - vec->nr_frames = 0;
> > - return vec;
> > -}
> > -EXPORT_SYMBOL(frame_vector_create);
> > -
> > -/**
> > - * frame_vector_destroy() - free memory allocated to carry frame vector
> > - * @vec: Frame vector to free
> > - *
> > - * Free structure allocated by frame_vector_create() to carry frames.
> > - */
> > -void frame_vector_destroy(struct frame_vector *vec)
> > -{
> > - /* Make sure put_vaddr_frames() got called properly... */
> > - VM_BUG_ON(vec->nr_frames > 0);
> > - if (!is_vmalloc_addr(vec))
> > - kfree(vec);
> > - else
> > - vfree(vec);
> > -}
> > -EXPORT_SYMBOL(frame_vector_destroy);
> > -
> > /**
> > * get_dump_page() - pin user page in memory while writing it to core dump
> > * @addr: user address
> > --
> > 2.4.2
> >
--
Jan Kara <jack at suse.cz>
SUSE Labs, CR
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