Merge "zram: optimize memory operations with clear_page()/copy_page()" (22b0bd6e) · Commits · e / devices / android_kernel_sony_msm8994

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);