GZIP compression offloading with QAT accelerator

This patch implement the hardware accelerator method in GZIP compression
in ZFS. When the ZFS pool is enabled GZIP compression, the compression
API will be automatically transferred to the hardware accelerator to
free up CPU resource and speed up the compression time.

* To enable Intel QAT hardware acceleration in ZOL you need have QAT
  hardware and driver installed:
  * QAT hardware DH8950:
  http://ark.intel.com/products/79483/Intel-QuickAssist-Adapter-8950
  * QAT driver:
  https://01.org/intel-quickassist-technology
* Start QAT driver in your system:
  service qat_service start
* Enable QAT in ZFS, e.g.:
  ./configure --with-qat=<qat-driver-path>/QAT1.6
  make
* Set GZIP compression in ZFS dataset:
  zfs set compression = gzip <dataset>
* Get QAT hardware statistics by:
  cat /proc/icp_dh895xcc_dev/qat
* To disable QAT in ZFS:
  insmod zfs.ko zfs_qat_disable=1

config/kernel.m4

@@ -4,6 +4,7 @@ dnl #
 AC_DEFUN([ZFS_AC_CONFIG_KERNEL], [
 	ZFS_AC_KERNEL
 	ZFS_AC_SPL
+	ZFS_AC_QAT
 	ZFS_AC_TEST_MODULE
 	ZFS_AC_KERNEL_OBJTOOL
 	ZFS_AC_KERNEL_CONFIG
@@ -468,6 +469,95 @@ AC_DEFUN([ZFS_AC_SPL], [
 	AC_SUBST(SPL_SYMBOLS)
 ])
 
+dnl #
+dnl # Detect the QAT module to be built against
+dnl # QAT provides hardware acceleration for data compression:
+dnl # 	https://01.org/intel-quickassist-technology
+dnl # * Download and install QAT driver from the above link
+dnl # * Start QAT driver in your system:
+dnl # 	service qat_service start
+dnl # * Enable QAT in ZFS, e.g.:
+dnl # 	./configure --with-qat=<qat-driver-path>/QAT1.6
+dnl #	make
+dnl # * Set GZIP compression in ZFS dataset:
+dnl # 	zfs set compression = gzip <dataset>
+dnl # Then the data written to this ZFS pool is compressed
+dnl # by QAT accelerator automatically, and de-compressed by
+dnl # QAT when read from the pool.
+dnl # * Get QAT hardware statistics by:
+dnl #	cat /proc/icp_dh895xcc_dev/qat
+dnl # * To disable QAT:
+dnl # 	insmod zfs.ko zfs_qat_disable=1
+dnl #
+AC_DEFUN([ZFS_AC_QAT], [
+	AC_ARG_WITH([qat],
+		AS_HELP_STRING([--with-qat=PATH],
+		[Path to qat source]),
+		AS_IF([test "$withval" = "yes"],
+			AC_MSG_ERROR([--with-qat=PATH requires a PATH]),
+			[qatsrc="$withval"]))
+
+	AC_ARG_WITH([qat-obj],
+		AS_HELP_STRING([--with-qat-obj=PATH],
+		[Path to qat build objects]),
+		[qatbuild="$withval"])
+
+	AS_IF([test ! -z "${qatsrc}"], [
+		AC_MSG_CHECKING([qat source directory])
+		AC_MSG_RESULT([$qatsrc])
+		QAT_SRC="${qatsrc}/quickassist"
+		AS_IF([ test ! -e "$QAT_SRC/include/cpa.h"], [
+			AC_MSG_ERROR([
+		*** Please make sure the qat driver package is installed
+		*** and specify the location of the qat source with the
+		*** '--with-qat=PATH' option then try again. Failed to
+		*** find cpa.h in:
+		${QAT_SRC}/include])
+		])
+	])
+
+	AS_IF([test ! -z "${qatsrc}"], [
+		AC_MSG_CHECKING([qat build directory])
+		AS_IF([test -z "$qatbuild"], [
+			qatbuild="${qatsrc}/build"
+		])
+
+		AC_MSG_RESULT([$qatbuild])
+		QAT_OBJ=${qatbuild}
+		AS_IF([ ! test -e "$QAT_OBJ/icp_qa_al.ko"], [
+			AC_MSG_ERROR([
+		*** Please make sure the qat driver is installed then try again.
+		*** Failed to find icp_qa_al.ko in:
+		$QAT_OBJ])
+		])
+
+		AC_SUBST(QAT_SRC)
+		AC_SUBST(QAT_OBJ)
+
+		AC_DEFINE(HAVE_QAT, 1,
+		[qat is enabled and existed])
+	])
+
+	dnl #
+	dnl # Detect the name used for the QAT Module.symvers file.
+	dnl #
+	AS_IF([test ! -z "${qatsrc}"], [
+		AC_MSG_CHECKING([qat file for module symbols])
+		QAT_SYMBOLS=$QAT_SRC/lookaside/access_layer/src/Module.symvers
+
+		AS_IF([test -r $QAT_SYMBOLS], [
+			AC_MSG_RESULT([$QAT_SYMBOLS])
+			AC_SUBST(QAT_SYMBOLS)
+		],[
+                       AC_MSG_ERROR([
+			*** Please make sure the qat driver is installed then try again.
+			*** Failed to find Module.symvers in:
+			$QAT_SYMBOLS])
+			])
+		])
+	])
+])
+
 dnl #
 dnl # Basic toolchain sanity check.
 dnl #

config/zfs-build.m4

@@ -81,6 +81,9 @@ AC_DEFUN([ZFS_AC_CONFIG], [
 	    [test "x$enable_linux_builtin" != xyes ])
 	AM_CONDITIONAL([WANT_DEVNAME2DEVID],
 	    [test "x$user_libudev" = xyes ])
+	AM_CONDITIONAL([CONFIG_QAT],
+	    [test "$ZFS_CONFIG" = kernel -o "$ZFS_CONFIG" = all] &&
+	    [test "x$qatsrc" != x ])
 ])
 
 dnl #

module/Makefile.in

@@ -11,6 +11,8 @@ INSTALL_MOD_DIR ?= extra
 ZFS_MODULE_CFLAGS += -include @SPL_OBJ@/spl_config.h
 ZFS_MODULE_CFLAGS += -include @abs_top_builddir@/zfs_config.h
 ZFS_MODULE_CFLAGS += -I@abs_top_srcdir@/include -I@SPL@/include -I@SPL@
+@CONFIG_QAT_TRUE@ZFS_MODULE_CFLAGS += -I@QAT_SRC@/include
+@CONFIG_QAT_TRUE@KBUILD_EXTRA_SYMBOLS += @QAT_SYMBOLS@
 export ZFS_MODULE_CFLAGS
 
 SUBDIR_TARGETS = icp

module/zfs/Makefile.in

@@ -114,6 +114,7 @@ $(MODULE)-objs += zrlock.o
 $(MODULE)-objs += zvol.o
 $(MODULE)-objs += dsl_destroy.o
 $(MODULE)-objs += dsl_userhold.o
+$(MODULE)-objs += qat_compress.o
 
 $(MODULE)-$(CONFIG_X86) += vdev_raidz_math_sse2.o
 $(MODULE)-$(CONFIG_X86) += vdev_raidz_math_ssse3.o

module/zfs/gzip.c

@@ -28,6 +28,7 @@
 
 #include <sys/debug.h>
 #include <sys/types.h>
+#include "qat_compress.h"
 
 #ifdef _KERNEL
 
@@ -56,6 +57,14 @@ gzip_compress(void *s_start, void *d_start, size_t s_len, size_t d_len, int n)
 
 	ASSERT(d_len <= s_len);
 
+	/* check if hardware accelerator can be used */
+	if (qat_use_accel(s_len)) {
+		if (qat_compress(QAT_COMPRESS, s_start,
+		    s_len, d_start, d_len, &dstlen) == CPA_STATUS_SUCCESS)
+			return ((size_t)dstlen);
+		/* if hardware compress fail, do it again with software */
+	}
+
 	if (compress_func(d_start, &dstlen, s_start, s_len, n) != Z_OK) {
 		if (d_len != s_len)
 			return (s_len);
@@ -75,6 +84,14 @@ gzip_decompress(void *s_start, void *d_start, size_t s_len, size_t d_len, int n)
 
 	ASSERT(d_len >= s_len);
 
+	/* check if hardware accelerator can be used */
+	if (qat_use_accel(d_len)) {
+		if (qat_compress(QAT_DECOMPRESS, s_start, s_len,
+		    d_start, d_len, &dstlen) == CPA_STATUS_SUCCESS)
+			return (0);
+		/* if hardware de-compress fail, do it again with software */
+	}
+
 	if (uncompress_func(d_start, &dstlen, s_start, s_len) != Z_OK)
 		return (-1);