Commit 0b62af28 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Andrew Morton
Browse files

i915: convert shmem_sg_free_table() to use a folio_batch 

Remove a few hidden compound_head() calls by converting the returned page
to a folio once and using the folio APIs.  We also only increment the
refcount on the folio once instead of once for each page.  Ideally, we
would have a for_each_sgt_folio macro, but until then this will do.

Link: https://lkml.kernel.org/r/20230621164557.3510324-5-willy@infradead.org


Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent bdadc6d8

drivers/gpu/drm/i915/gem/i915_gem_shmem.c

+31 −24
Original line number Diff line number Diff line
@@ -19,13 +19,13 @@ 
#include "i915_trace.h"



/*

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

 * ref count of those pages.

 * Move folios to appropriate lru and release the batch, decrementing the

 * ref count of those folios.

 */

static void check_release_pagevec(struct pagevec *pvec)

static void check_release_folio_batch(struct folio_batch *fbatch)

{

	check_move_unevictable_pages(pvec);

	__pagevec_release(pvec);

	check_move_unevictable_folios(fbatch);

	__folio_batch_release(fbatch);

	cond_resched();

}
@@ -33,24 +33,29 @@ void shmem_sg_free_table(struct sg_table *st, struct address_space *mapping, 
			 bool dirty, bool backup)

{

	struct sgt_iter sgt_iter;

	struct pagevec pvec;

	struct folio_batch fbatch;

	struct folio *last = NULL;

	struct page *page;



	mapping_clear_unevictable(mapping);



	pagevec_init(&pvec);

	folio_batch_init(&fbatch);

	for_each_sgt_page(page, sgt_iter, st) {

		if (dirty)

			set_page_dirty(page);

		struct folio *folio = page_folio(page);



		if (folio == last)

			continue;

		last = folio;

		if (dirty)

			folio_mark_dirty(folio);

		if (backup)

			mark_page_accessed(page);

			folio_mark_accessed(folio);



		if (!pagevec_add(&pvec, page))

			check_release_pagevec(&pvec);

		if (!folio_batch_add(&fbatch, folio))

			check_release_folio_batch(&fbatch);

	}

	if (pagevec_count(&pvec))

		check_release_pagevec(&pvec);

	if (fbatch.nr)

		check_release_folio_batch(&fbatch);



	sg_free_table(st);

}
@@ -63,8 +68,7 @@ int shmem_sg_alloc_table(struct drm_i915_private *i915, struct sg_table *st, 
	unsigned int page_count; /* restricted by sg_alloc_table */

	unsigned long i;

	struct scatterlist *sg;

	struct page *page;

	unsigned long last_pfn = 0;	/* suppress gcc warning */

	unsigned long next_pfn = 0;	/* suppress gcc warning */

	gfp_t noreclaim;

	int ret;
@@ -95,6 +99,7 @@ int shmem_sg_alloc_table(struct drm_i915_private *i915, struct sg_table *st, 
	sg = st->sgl;

	st->nents = 0;

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

		struct folio *folio;

		const unsigned int shrink[] = {

			I915_SHRINK_BOUND | I915_SHRINK_UNBOUND,

			0,
@@ -103,12 +108,12 @@ int shmem_sg_alloc_table(struct drm_i915_private *i915, struct sg_table *st, 


		do {

			cond_resched();

			page = shmem_read_mapping_page_gfp(mapping, i, gfp);

			if (!IS_ERR(page))

			folio = shmem_read_folio_gfp(mapping, i, gfp);

			if (!IS_ERR(folio))

				break;



			if (!*s) {

				ret = PTR_ERR(page);

				ret = PTR_ERR(folio);

				goto err_sg;

			}
@@ -147,19 +152,21 @@ int shmem_sg_alloc_table(struct drm_i915_private *i915, struct sg_table *st, 


		if (!i ||

		    sg->length >= max_segment ||

		    page_to_pfn(page) != last_pfn + 1) {

		    folio_pfn(folio) != next_pfn) {

			if (i)

				sg = sg_next(sg);



			st->nents++;

			sg_set_page(sg, page, PAGE_SIZE, 0);

			sg_set_folio(sg, folio, folio_size(folio), 0);

		} else {

			sg->length += PAGE_SIZE;

			/* XXX: could overflow? */

			sg->length += folio_size(folio);

		}

		last_pfn = page_to_pfn(page);

		next_pfn = folio_pfn(folio) + folio_nr_pages(folio);

		i += folio_nr_pages(folio) - 1;



		/* Check that the i965g/gm workaround works. */

		GEM_BUG_ON(gfp & __GFP_DMA32 && last_pfn >= 0x00100000UL);

		GEM_BUG_ON(gfp & __GFP_DMA32 && next_pfn >= 0x00100000UL);

	}

	if (sg) /* loop terminated early; short sg table */

		sg_mark_end(sg);