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Commit 42e99bd9 authored by Jiang Liu's avatar Jiang Liu Committed by Greg Kroah-Hartman
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zram: optimize memory operations with clear_page()/copy_page() 



Some architectures provides architecture-specific, optimized version of
clear_page()/copy_page(), which may have better performance than
memset()/memcpy(). So use clear_page()/copy_page() to optimize zram
performance if possible.

Signed-off-by: default avatarJiang Liu <jiang.liu@huawei.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 0f0e3ba3

drivers/staging/zram/zram_drv.c

+16 −11
Original line number Diff line number Diff line
@@ -128,23 +128,26 @@ static void zram_free_page(struct zram *zram, size_t index) 
	meta->table[index].size = 0;

}



static inline int is_partial_io(struct bio_vec *bvec)

{

	return bvec->bv_len != PAGE_SIZE;

}



static void handle_zero_page(struct bio_vec *bvec)

{

	struct page *page = bvec->bv_page;

	void *user_mem;



	user_mem = kmap_atomic(page);

	if (is_partial_io(bvec))

		memset(user_mem + bvec->bv_offset, 0, bvec->bv_len);

	else

		clear_page(user_mem);

	kunmap_atomic(user_mem);



	flush_dcache_page(page);

}



static inline int is_partial_io(struct bio_vec *bvec)

{

	return bvec->bv_len != PAGE_SIZE;

}



static int zram_decompress_page(struct zram *zram, char *mem, u32 index)

{

	int ret = LZO_E_OK;
@@ -154,13 +157,13 @@ static int zram_decompress_page(struct zram *zram, char *mem, u32 index) 
	unsigned long handle = meta->table[index].handle;



	if (!handle || zram_test_flag(meta, index, ZRAM_ZERO)) {

		memset(mem, 0, PAGE_SIZE);

		clear_page(mem);

		return 0;

	}



	cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_RO);

	if (meta->table[index].size == PAGE_SIZE)

		memcpy(mem, cmem, PAGE_SIZE);

		copy_page(mem, cmem);

	else

		ret = lzo1x_decompress_safe(cmem, meta->table[index].size,

						mem, &clen);
@@ -309,11 +312,13 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, 
	}

	cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_WO);



	if ((clen == PAGE_SIZE) && !is_partial_io(bvec))

	if ((clen == PAGE_SIZE) && !is_partial_io(bvec)) {

		src = kmap_atomic(page);

	memcpy(cmem, src, clen);

	if ((clen == PAGE_SIZE) && !is_partial_io(bvec))

		copy_page(cmem, src);

		kunmap_atomic(src);

	} else {

		memcpy(cmem, src, clen);

	}



	zs_unmap_object(meta->mem_pool, handle);