Commit a5cd78ac authored by Sergey Senozhatsky's avatar Sergey Senozhatsky Committed by Andrew Morton
Browse files

zram: factor out ZRAM_SAME write 

Handling of ZRAM_SAME now uses a goto to the final stages of
zram_write_page() plus it introduces a branch and flags variable, which is
not making the code any simpler.  In reality, we can handle ZRAM_SAME
immediately when we detect such pages and remove a goto and a branch.

Factor out ZRAM_SAME handling into a separate routine to simplify
zram_write_page().

Link: https://lkml.kernel.org/r/20241218063513.297475-4-senozhatsky@chromium.org


Signed-off-by: default avatarSergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent b4444a84

drivers/block/zram/zram_drv.c

+21 −16
Original line number Diff line number Diff line
@@ -1625,6 +1625,20 @@ static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec, 
	return zram_read_page(zram, bvec->bv_page, index, bio);

}



static int write_same_filled_page(struct zram *zram, unsigned long fill,

				  u32 index)

{

	zram_slot_lock(zram, index);

	zram_set_flag(zram, index, ZRAM_SAME);

	zram_set_handle(zram, index, fill);

	zram_slot_unlock(zram, index);



	atomic64_inc(&zram->stats.same_pages);

	atomic64_inc(&zram->stats.pages_stored);



	return 0;

}



static int zram_write_page(struct zram *zram, struct page *page, u32 index)

{

	int ret = 0;
@@ -1634,7 +1648,7 @@ static int zram_write_page(struct zram *zram, struct page *page, u32 index) 
	void *src, *dst, *mem;

	struct zcomp_strm *zstrm;

	unsigned long element = 0;

	enum zram_pageflags flags = 0;

	bool same_filled;



	/* First, free memory allocated to this slot (if any) */

	zram_slot_lock(zram, index);
@@ -1642,14 +1656,10 @@ static int zram_write_page(struct zram *zram, struct page *page, u32 index) 
	zram_slot_unlock(zram, index);



	mem = kmap_local_page(page);

	if (page_same_filled(mem, &element)) {

		kunmap_local(mem);

		/* Free memory associated with this sector now. */

		flags = ZRAM_SAME;

		atomic64_inc(&zram->stats.same_pages);

		goto out;

	}

	same_filled = page_same_filled(mem, &element);

	kunmap_local(mem);

	if (same_filled)

		return write_same_filled_page(zram, element, index);



compress_again:

	zstrm = zcomp_stream_get(zram->comps[ZRAM_PRIMARY_COMP]);
@@ -1728,7 +1738,7 @@ static int zram_write_page(struct zram *zram, struct page *page, u32 index) 
	zcomp_stream_put(zram->comps[ZRAM_PRIMARY_COMP]);

	zs_unmap_object(zram->mem_pool, handle);

	atomic64_add(comp_len, &zram->stats.compr_data_size);

out:



	zram_slot_lock(zram, index);

	if (comp_len == PAGE_SIZE) {

		zram_set_flag(zram, index, ZRAM_HUGE);
@@ -1736,13 +1746,8 @@ static int zram_write_page(struct zram *zram, struct page *page, u32 index) 
		atomic64_inc(&zram->stats.huge_pages_since);

	}



	if (flags) {

		zram_set_flag(zram, index, flags);

		zram_set_handle(zram, index, element);

	}  else {

	zram_set_handle(zram, index, handle);

	zram_set_obj_size(zram, index, comp_len);

	}

	zram_slot_unlock(zram, index);



	/* Update stats */