This patchset makes zram to use crypto API in order to support more compression algorithm. The reason we need to support vairous compression algorithms is that zram's performance is highly depend on workload and compression algorithm and architecture. Every compression algorithm has it's own strong point. For example, zlib is the best for compression ratio, but, it's (de)compression speed is rather slow. Against my expectation, in my kernel build test with zram swap, in low-memory condition on x86, zlib shows best performance than others. In this case, I guess that compression ratio is the most important factor. Unlike this situation, on ARM, maybe fast (de)compression speed is the most important because it's computation speed is slower than x86. Anyway, there is a concern from Sergey to use crypto API in zram. Current crypto API has a limitation that always require tfm object to (de)compress something because some of (de)compression function requires scratch buffer embedded on tfm even if some of (de)compression function doesn't require it. Due to above reason, using crypto API rather than calling compression library directly causes more memory footprint and this is why zram doesn't use crypto API before. In this patchset, crypto compress noctx API is introduced to reduce memory footprint caused by maintaining multiple tfm and zram uses it. Before noctx API, zram's performace is down-graded if tfm is insufficient. But, after applying noctx API, performace is restored. This addresses Sergey's concern perfectly and provides possibility to use various compression algorithm in zram. Following is zram's read performance number. * iozone -t 4 -R -r 16K -s 60M -I +Z -i 0 -i 1 * max_stream is set to 1 * Output is in Kbytes/sec zram-base vs zram-crypto vs zram-crypto-noctx Read 10411701.88 6426911.62 9423894.38 Re-read 10017386.62 6428218.88 11000063.50 Thanks. Joonsoo Kim (8): crypto: support (de)compression API that doesn't require tfm object crypto/lzo: support decompress_noctx crypyo/lz4: support decompress_noctx crypto/lz4hc: support decompress_noctx crypto/842: support decompress_noctx zram: change zcomp_compress interface zram: use crypto API for compression zram: use decompress_noctx crypto/842.c | 10 +++- crypto/compress.c | 20 ++++++++ crypto/crypto_null.c | 4 +- crypto/deflate.c | 4 +- crypto/lz4.c | 19 ++++++- crypto/lz4hc.c | 19 ++++++- crypto/lzo.c | 20 +++++++- drivers/block/zram/Kconfig | 13 +---- drivers/block/zram/Makefile | 4 +- drivers/block/zram/zcomp.c | 113 +++++++++++++++++++++++++---------------- drivers/block/zram/zcomp.h | 44 +++++++--------- drivers/block/zram/zcomp_lz4.c | 47 ----------------- drivers/block/zram/zcomp_lz4.h | 17 ------- drivers/block/zram/zcomp_lzo.c | 47 ----------------- drivers/block/zram/zcomp_lzo.h | 17 ------- drivers/block/zram/zram_drv.c | 29 +++++++---- include/linux/crypto.h | 31 +++++++++++ 17 files changed, 229 insertions(+), 229 deletions(-) delete mode 100644 drivers/block/zram/zcomp_lz4.c delete mode 100644 drivers/block/zram/zcomp_lz4.h delete mode 100644 drivers/block/zram/zcomp_lzo.c delete mode 100644 drivers/block/zram/zcomp_lzo.h -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
