Commit fb4b4927 authored by Kuo-Hsin Yang's avatar Kuo-Hsin Yang Committed by Chris Wilson
Browse files

drm/gem: Mark pinned pages as unevictable 

The gem drivers use shmemfs to allocate backing storage for gem objects.
On Samsung Chromebook Plus, the drm/rockchip driver may call
rockchip_gem_get_pages -> drm_gem_get_pages -> shmem_read_mapping_page
to pin a lot of pages, breaking the page reclaim mechanism and causing
oom-killer invocation.

E.g. when the size of a zone is 3.9 GiB, the inactive_ratio is 5. If
active_anon / inactive_anon < 5 and all pages in the inactive_anon lru
are pinned, page reclaim would keep scanning inactive_anon lru without
reclaiming memory. It breaks page reclaim when the rockchip driver only
pins about 1/6 of the anon lru pages.

Mark these pinned pages as unevictable to avoid the premature oom-killer
invocation. See also similar patch on i915 driver [1].

[1]: https://patchwork.freedesktop.org/patch/msgid/20181106132324.17390-1-chris@chris-wilson.co.uk



Signed-off-by: default avatarKuo-Hsin Yang <vovoy@chromium.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190108074517.209860-1-vovoy@chromium.org
parent 2513147d

drivers/gpu/drm/drm_gem.c

+33 −3
Original line number Diff line number Diff line
@@ -37,6 +37,7 @@ 
#include <linux/shmem_fs.h>

#include <linux/dma-buf.h>

#include <linux/mem_encrypt.h>

#include <linux/pagevec.h>

#include <drm/drmP.h>

#include <drm/drm_vma_manager.h>

#include <drm/drm_gem.h>
@@ -526,6 +527,17 @@ int drm_gem_create_mmap_offset(struct drm_gem_object *obj) 
}

EXPORT_SYMBOL(drm_gem_create_mmap_offset);



/*

 * Move pages to appropriate lru and release the pagevec, decrementing the

 * ref count of those pages.

 */

static void drm_gem_check_release_pagevec(struct pagevec *pvec)

{

	check_move_unevictable_pages(pvec);

	__pagevec_release(pvec);

	cond_resched();

}



/**

 * drm_gem_get_pages - helper to allocate backing pages for a GEM object

 * from shmem
@@ -551,6 +563,7 @@ struct page **drm_gem_get_pages(struct drm_gem_object *obj) 
{

	struct address_space *mapping;

	struct page *p, **pages;

	struct pagevec pvec;

	int i, npages;



	/* This is the shared memory object that backs the GEM resource */
@@ -568,6 +581,8 @@ struct page **drm_gem_get_pages(struct drm_gem_object *obj) 
	if (pages == NULL)

		return ERR_PTR(-ENOMEM);



	mapping_set_unevictable(mapping);



	for (i = 0; i < npages; i++) {

		p = shmem_read_mapping_page(mapping, i);

		if (IS_ERR(p))
@@ -586,8 +601,14 @@ struct page **drm_gem_get_pages(struct drm_gem_object *obj) 
	return pages;



fail:

	while (i--)

		put_page(pages[i]);

	mapping_clear_unevictable(mapping);

	pagevec_init(&pvec);

	while (i--) {

		if (!pagevec_add(&pvec, pages[i]))

			drm_gem_check_release_pagevec(&pvec);

	}

	if (pagevec_count(&pvec))

		drm_gem_check_release_pagevec(&pvec);



	kvfree(pages);

	return ERR_CAST(p);
@@ -605,6 +626,11 @@ void drm_gem_put_pages(struct drm_gem_object *obj, struct page **pages, 
		bool dirty, bool accessed)

{

	int i, npages;

	struct address_space *mapping;

	struct pagevec pvec;



	mapping = file_inode(obj->filp)->i_mapping;

	mapping_clear_unevictable(mapping);



	/* We already BUG_ON() for non-page-aligned sizes in

	 * drm_gem_object_init(), so we should never hit this unless
@@ -614,6 +640,7 @@ void drm_gem_put_pages(struct drm_gem_object *obj, struct page **pages, 


	npages = obj->size >> PAGE_SHIFT;



	pagevec_init(&pvec);

	for (i = 0; i < npages; i++) {

		if (dirty)

			set_page_dirty(pages[i]);
@@ -622,8 +649,11 @@ void drm_gem_put_pages(struct drm_gem_object *obj, struct page **pages, 
			mark_page_accessed(pages[i]);



		/* Undo the reference we took when populating the table */

		put_page(pages[i]);

		if (!pagevec_add(&pvec, pages[i]))

			drm_gem_check_release_pagevec(&pvec);

	}

	if (pagevec_count(&pvec))

		drm_gem_check_release_pagevec(&pvec);



	kvfree(pages);

}

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