diff --git a/backend.c b/backend.c
index d82d49487c..a92b1e3c02 100644
--- a/backend.c
+++ b/backend.c
@@ -22,29 +22,17 @@
  *
  */
 #include <unistd.h>
-#include <fcntl.h>
 #include <string.h>
-#include <limits.h>
 #include <signal.h>
-#include <time.h>
-#include <locale.h>
 #include <assert.h>
-#include <time.h>
 #include <inttypes.h>
 #include <sys/stat.h>
 #include <sys/wait.h>
-#include <sys/ipc.h>
-#include <sys/mman.h>
 #include <math.h>
 
 #include "fio.h"
-#ifndef FIO_NO_HAVE_SHM_H
-#include <sys/shm.h>
-#endif
-#include "hash.h"
 #include "smalloc.h"
 #include "verify.h"
-#include "trim.h"
 #include "diskutil.h"
 #include "cgroup.h"
 #include "profile.h"
diff --git a/blktrace.c b/blktrace.c
index 4b791d7eb3..6e4d0a4c96 100644
--- a/blktrace.c
+++ b/blktrace.c
@@ -3,10 +3,8 @@
  */
 #include <stdio.h>
 #include <stdlib.h>
-#include <sys/stat.h>
 #include <sys/ioctl.h>
 #include <linux/fs.h>
-#include <dirent.h>
 
 #include "flist.h"
 #include "fio.h"
diff --git a/cconv.c b/cconv.c
index 92996b1e43..dbe0071a1d 100644
--- a/cconv.c
+++ b/cconv.c
@@ -1,5 +1,6 @@
 #include <string.h>
 
+#include "log.h"
 #include "thread_options.h"
 
 static void string_to_cpu(char **dst, const uint8_t *src)
diff --git a/cgroup.c b/cgroup.c
index 4fab977aeb..380e37e487 100644
--- a/cgroup.c
+++ b/cgroup.c
@@ -5,7 +5,6 @@
 #include <stdlib.h>
 #include <mntent.h>
 #include <sys/stat.h>
-#include <sys/types.h>
 #include "fio.h"
 #include "flist.h"
 #include "cgroup.h"
diff --git a/client.c b/client.c
index bff0adc0d9..43825d9e27 100644
--- a/client.c
+++ b/client.c
@@ -1,13 +1,11 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
-#include <limits.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <sys/poll.h>
 #include <sys/types.h>
 #include <sys/stat.h>
-#include <sys/wait.h>
 #include <sys/socket.h>
 #include <sys/un.h>
 #include <netinet/in.h>
@@ -23,7 +21,7 @@
 #include "server.h"
 #include "flist.h"
 #include "hash.h"
-#include "verify.h"
+#include "verify-state.h"
 
 static void handle_du(struct fio_client *client, struct fio_net_cmd *cmd);
 static void handle_ts(struct fio_client *client, struct fio_net_cmd *cmd);
diff --git a/client.h b/client.h
index 90082a3491..29e84d0dc2 100644
--- a/client.h
+++ b/client.h
@@ -1,7 +1,6 @@
 #ifndef CLIENT_H
 #define CLIENT_H
 
-#include <sys/socket.h>
 #include <sys/un.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
@@ -10,7 +9,6 @@
 #include "stat.h"
 
 struct fio_net_cmd;
-struct client_ops;
 
 enum {
 	Client_created		= 0,
@@ -83,6 +81,8 @@ typedef void (client_eta_op)(struct jobs_eta *je);
 typedef void (client_timed_out_op)(struct fio_client *);
 typedef void (client_jobs_eta_op)(struct fio_client *client, struct jobs_eta *je);
 
+extern struct client_ops fio_client_ops;
+
 struct client_ops {
 	client_cmd_op		*text;
 	client_cmd_op		*disk_util;
@@ -105,8 +105,6 @@ struct client_ops {
 	uint32_t client_type;
 };
 
-extern struct client_ops fio_client_ops;
-
 struct client_eta {
 	unsigned int pending;
 	struct jobs_eta eta;
diff --git a/compiler/compiler.h b/compiler/compiler.h
index 91a988369e..8488aa0d4b 100644
--- a/compiler/compiler.h
+++ b/compiler/compiler.h
@@ -1,6 +1,5 @@
 #ifndef FIO_COMPILER_H
 #define FIO_COMPILER_H
-#include <assert.h>
 
 #if __GNUC__ >= 4
 #include "compiler-gcc4.h"
diff --git a/crc/crc32.c b/crc/crc32.c
index 4140a8d4ad..e35f5d9308 100644
--- a/crc/crc32.c
+++ b/crc/crc32.c
@@ -15,7 +15,6 @@
    along with this program; if not, write to the Free Software Foundation,
    Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
 
-#include <inttypes.h>
 #include "crc32.h"
 
 static const uint32_t crctab[256] = {
diff --git a/crc/crc32.h b/crc/crc32.h
index a37d7ada96..6378e815b1 100644
--- a/crc/crc32.h
+++ b/crc/crc32.h
@@ -18,6 +18,8 @@
 #ifndef CRC32_H
 #define CRC32_H
 
+#include <inttypes.h>
+
 extern uint32_t fio_crc32(const void * const, unsigned long);
 
 #endif
diff --git a/crc/crc32c-intel.c b/crc/crc32c-intel.c
index 05a087dcb6..9a2cefdedc 100644
--- a/crc/crc32c-intel.c
+++ b/crc/crc32c-intel.c
@@ -1,10 +1,3 @@
-#include <inttypes.h>
-#include <string.h>
-#include <unistd.h>
-#include <stdlib.h>
-#include <signal.h>
-#include <sys/types.h>
-#include <sys/wait.h>
 #include "crc32c.h"
 
 /*
diff --git a/crc/crc32c.c b/crc/crc32c.c
index f6fc688748..34944aea92 100644
--- a/crc/crc32c.c
+++ b/crc/crc32c.c
@@ -30,8 +30,6 @@
  * any later version.
  *
  */
-#include <inttypes.h>
-
 #include "crc32c.h"
 
 /*
diff --git a/crc/crc32c.h b/crc/crc32c.h
index be03c1a27c..60f6014196 100644
--- a/crc/crc32c.h
+++ b/crc/crc32c.h
@@ -18,6 +18,8 @@
 #ifndef CRC32C_H
 #define CRC32C_H
 
+#include <inttypes.h>
+
 #include "../arch/arch.h"
 #include "../lib/types.h"
 
diff --git a/crc/md5.c b/crc/md5.c
index 64fe48a9a4..ade4f69721 100644
--- a/crc/md5.c
+++ b/crc/md5.c
@@ -2,7 +2,6 @@
  * Shamelessly lifted from the 2.6 kernel (crypto/md5.c)
  */
 #include <string.h>
-#include <stdint.h>
 #include "md5.h"
 
 static void md5_transform(uint32_t *hash, uint32_t const *in)
diff --git a/crc/sha1.h b/crc/sha1.h
index 75317f76c6..416199baff 100644
--- a/crc/sha1.h
+++ b/crc/sha1.h
@@ -1,6 +1,8 @@
 #ifndef FIO_SHA1
 #define FIO_SHA1
 
+#include <inttypes.h>
+
 /*
  * Based on the Mozilla SHA1 (see mozilla-sha1/sha1.h),
  * optimized to do word accesses rather than byte accesses,
diff --git a/crc/sha256.c b/crc/sha256.c
index 2fd17a32d1..2b39c42e22 100644
--- a/crc/sha256.c
+++ b/crc/sha256.c
@@ -17,7 +17,6 @@
  *
  */
 #include <string.h>
-#include <inttypes.h>
 
 #include "../lib/bswap.h"
 #include "sha256.h"
diff --git a/crc/sha256.h b/crc/sha256.h
index b6360336d2..b904c7d1d3 100644
--- a/crc/sha256.h
+++ b/crc/sha256.h
@@ -1,6 +1,8 @@
 #ifndef FIO_SHA256_H
 #define FIO_SHA256_H
 
+#include <inttypes.h>
+
 #define SHA256_DIGEST_SIZE	32
 #define SHA256_BLOCK_SIZE	64
 
diff --git a/crc/sha3.c b/crc/sha3.c
index 2685dce60f..c136550aae 100644
--- a/crc/sha3.c
+++ b/crc/sha3.c
@@ -13,7 +13,6 @@
  *
  */
 #include <string.h>
-#include <inttypes.h>
 
 #include "../os/os.h"
 
diff --git a/crc/sha512.c b/crc/sha512.c
index e069a4489e..f599cdcc82 100644
--- a/crc/sha512.c
+++ b/crc/sha512.c
@@ -12,7 +12,6 @@
  */
 
 #include <string.h>
-#include <inttypes.h>
 
 #include "../lib/bswap.h"
 #include "sha512.h"
diff --git a/crc/sha512.h b/crc/sha512.h
index f8b2112aed..5adf6271cd 100644
--- a/crc/sha512.h
+++ b/crc/sha512.h
@@ -1,6 +1,8 @@
 #ifndef FIO_SHA512_H
 #define FIO_SHA512_H
 
+#include <inttypes.h>
+
 struct fio_sha512_ctx {
 	uint64_t state[8];
 	uint32_t count[4];
diff --git a/crc/test.c b/crc/test.c
index b119872625..b57f07a4d7 100644
--- a/crc/test.c
+++ b/crc/test.c
@@ -1,11 +1,12 @@
+#include <inttypes.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
-#include "../fio.h"
 #include "../gettime.h"
 #include "../fio_time.h"
-#include "../verify.h"
+#include "../lib/rand.h"
+#include "../os/os.h"
 
 #include "../crc/md5.h"
 #include "../crc/crc64.h"
diff --git a/debug.c b/debug.c
index 2bee5078c1..d1e2987ba3 100644
--- a/debug.c
+++ b/debug.c
@@ -1,7 +1,8 @@
+#include <assert.h>
 #include <stdarg.h>
-#include <sys/types.h>
-#include <unistd.h>
+
 #include "debug.h"
+#include "log.h"
 
 #ifdef FIO_INC_DEBUG
 void __dprint(int type, const char *str, ...)
diff --git a/debug.h b/debug.h
index 1765fdb61e..8a8cf8710e 100644
--- a/debug.h
+++ b/debug.h
@@ -1,9 +1,7 @@
 #ifndef FIO_DEBUG_H
 #define FIO_DEBUG_H
 
-#include <assert.h>
 #include "lib/types.h"
-#include "log.h"
 
 enum {
 	FD_PROCESS	= 0,
diff --git a/diskutil.c b/diskutil.c
index dd8fc6a20b..b973120c1a 100644
--- a/diskutil.c
+++ b/diskutil.c
@@ -1,13 +1,10 @@
 #include <stdio.h>
 #include <string.h>
-#include <sys/time.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/sysmacros.h>
 #include <dirent.h>
 #include <libgen.h>
-#include <math.h>
-#include <assert.h>
 #ifdef CONFIG_VALGRIND_DEV
 #include <valgrind/drd.h>
 #else
diff --git a/diskutil.h b/diskutil.h
index c1035785c0..15ec681a44 100644
--- a/diskutil.h
+++ b/diskutil.h
@@ -3,7 +3,6 @@
 #include "json.h"
 #define FIO_DU_NAME_SZ		64
 
-#include "lib/output_buffer.h"
 #include "helper_thread.h"
 #include "fio_sem.h"
 
diff --git a/engines/e4defrag.c b/engines/e4defrag.c
index 4b444888aa..3619450d29 100644
--- a/engines/e4defrag.c
+++ b/engines/e4defrag.c
@@ -9,11 +9,7 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <stdio.h>
-#include <stdlib.h>
-#include <unistd.h>
-#include <sys/uio.h>
 #include <errno.h>
-#include <assert.h>
 #include <fcntl.h>
 
 #include "../fio.h"
diff --git a/engines/falloc.c b/engines/falloc.c
index 2b00d525d6..bb3ac85045 100644
--- a/engines/falloc.c
+++ b/engines/falloc.c
@@ -9,11 +9,7 @@
  *
  */
 #include <stdio.h>
-#include <stdlib.h>
-#include <unistd.h>
-#include <sys/uio.h>
 #include <errno.h>
-#include <assert.h>
 #include <fcntl.h>
 
 #include "../fio.h"
diff --git a/engines/filecreate.c b/engines/filecreate.c
index 0c3bcdd6b1..6fa041cdba 100644
--- a/engines/filecreate.c
+++ b/engines/filecreate.c
@@ -5,12 +5,10 @@
  * of the file creation.
  */
 #include <stdio.h>
-#include <unistd.h>
 #include <fcntl.h>
 #include <errno.h>
 
 #include "../fio.h"
-#include "../filehash.h"
 
 struct fc_data {
 	enum fio_ddir stat_ddir;
diff --git a/engines/ftruncate.c b/engines/ftruncate.c
index e86dbac009..14e115f221 100644
--- a/engines/ftruncate.c
+++ b/engines/ftruncate.c
@@ -6,16 +6,10 @@
  * DDIR_WRITE does ftruncate
  *
  */
-#include <stdio.h>
-#include <stdlib.h>
-#include <unistd.h>
-#include <sys/uio.h>
 #include <errno.h>
-#include <assert.h>
-#include <fcntl.h>
+#include <unistd.h>
 
 #include "../fio.h"
-#include "../filehash.h"
 
 static int fio_ftruncate_queue(struct thread_data *td, struct io_u *io_u)
 {
diff --git a/engines/libaio.c b/engines/libaio.c
index e0d7cbbafb..7d59df3869 100644
--- a/engines/libaio.c
+++ b/engines/libaio.c
@@ -4,11 +4,9 @@
  * IO engine using the Linux native aio interface.
  *
  */
-#include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <errno.h>
-#include <assert.h>
 #include <libaio.h>
 
 #include "../fio.h"
diff --git a/engines/mmap.c b/engines/mmap.c
index ea7179da23..9dbefc8214 100644
--- a/engines/mmap.c
+++ b/engines/mmap.c
@@ -7,7 +7,6 @@
  */
 #include <stdio.h>
 #include <stdlib.h>
-#include <unistd.h>
 #include <errno.h>
 #include <sys/mman.h>
 
diff --git a/engines/mtd.c b/engines/mtd.c
index b4a660041c..5f822fc1f5 100644
--- a/engines/mtd.c
+++ b/engines/mtd.c
@@ -4,17 +4,14 @@
  * IO engine that reads/writes from MTD character devices.
  *
  */
-#include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <unistd.h>
 #include <errno.h>
 #include <sys/ioctl.h>
 #include <mtd/mtd-user.h>
 
 #include "../fio.h"
 #include "../optgroup.h"
-#include "../verify.h"
 #include "../oslib/libmtd.h"
 
 static libmtd_t desc;
diff --git a/engines/net.c b/engines/net.c
index 37d44fd803..9b385b0cf0 100644
--- a/engines/net.c
+++ b/engines/net.c
@@ -9,13 +9,11 @@
 #include <unistd.h>
 #include <signal.h>
 #include <errno.h>
-#include <assert.h>
 #include <netinet/in.h>
 #include <netinet/tcp.h>
 #include <arpa/inet.h>
 #include <netdb.h>
 #include <sys/poll.h>
-#include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/socket.h>
 #include <sys/un.h>
diff --git a/engines/null.c b/engines/null.c
index 0cfc22ad9e..8c26ad7179 100644
--- a/engines/null.c
+++ b/engines/null.c
@@ -13,10 +13,7 @@
  * LD_LIBRARY_PATH=./engines ./fio examples/cpp_null.fio
  *
  */
-#include <stdio.h>
 #include <stdlib.h>
-#include <unistd.h>
-#include <errno.h>
 #include <assert.h>
 
 #include "../fio.h"
diff --git a/engines/sg.c b/engines/sg.c
index f240755595..7b18c28ef2 100644
--- a/engines/sg.c
+++ b/engines/sg.c
@@ -8,7 +8,6 @@
 #include <stdlib.h>
 #include <unistd.h>
 #include <errno.h>
-#include <assert.h>
 #include <sys/poll.h>
 
 #include "../fio.h"
diff --git a/engines/splice.c b/engines/splice.c
index d5d8ab0eba..d322f40212 100644
--- a/engines/splice.c
+++ b/engines/splice.c
@@ -9,7 +9,6 @@
 #include <stdlib.h>
 #include <unistd.h>
 #include <errno.h>
-#include <assert.h>
 #include <sys/poll.h>
 #include <sys/mman.h>
 
diff --git a/engines/sync.c b/engines/sync.c
index 26b98b60e2..d5b4012f80 100644
--- a/engines/sync.c
+++ b/engines/sync.c
@@ -10,7 +10,6 @@
 #include <unistd.h>
 #include <sys/uio.h>
 #include <errno.h>
-#include <assert.h>
 
 #include "../fio.h"
 #include "../optgroup.h"
diff --git a/eta.c b/eta.c
index 3126f217d4..2d549ee9c8 100644
--- a/eta.c
+++ b/eta.c
@@ -2,7 +2,6 @@
  * Status and ETA code
  */
 #include <unistd.h>
-#include <fcntl.h>
 #include <string.h>
 #ifdef CONFIG_VALGRIND_DEV
 #include <valgrind/drd.h>
diff --git a/fifo.c b/fifo.c
index 98737e9c83..ac0d21576d 100644
--- a/fifo.c
+++ b/fifo.c
@@ -24,6 +24,7 @@
 #include <string.h>
 
 #include "fifo.h"
+#include "minmax.h"
 
 struct fifo *fifo_alloc(unsigned int size)
 {
diff --git a/fifo.h b/fifo.h
index 5e3d33967a..61cc5a87bd 100644
--- a/fifo.h
+++ b/fifo.h
@@ -20,7 +20,6 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  *
  */
-#include "minmax.h"
 
 struct fifo {
 	unsigned char *buffer;	/* the buffer holding the data */
diff --git a/filesetup.c b/filesetup.c
index 7cbce1327f..c115f7b168 100644
--- a/filesetup.c
+++ b/filesetup.c
@@ -5,8 +5,6 @@
 #include <dirent.h>
 #include <libgen.h>
 #include <sys/stat.h>
-#include <sys/mman.h>
-#include <sys/types.h>
 
 #include "fio.h"
 #include "smalloc.h"
diff --git a/fio.c b/fio.c
index 7b61ffca34..f19db1be6f 100644
--- a/fio.c
+++ b/fio.c
@@ -21,12 +21,7 @@
  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  *
  */
-#include <unistd.h>
-#include <locale.h>
-#include <time.h>
-
 #include "fio.h"
-#include "smalloc.h"
 
 int main(int argc, char *argv[], char *envp[])
 {
diff --git a/fio.h b/fio.h
index 9551048745..488fa9a62e 100644
--- a/fio.h
+++ b/fio.h
@@ -27,6 +27,7 @@
 #include "ioengines.h"
 #include "iolog.h"
 #include "helpers.h"
+#include "minmax.h"
 #include "options.h"
 #include "profile.h"
 #include "fio_time.h"
diff --git a/fio_sem.c b/fio_sem.c
index 20fcfccc02..3b48061cd2 100644
--- a/fio_sem.c
+++ b/fio_sem.c
@@ -1,3 +1,4 @@
+#include <stdio.h>
 #include <string.h>
 #include <sys/mman.h>
 #include <assert.h>
@@ -7,7 +8,6 @@
 #define RUNNING_ON_VALGRIND 0
 #endif
 
-#include "log.h"
 #include "fio_sem.h"
 #include "pshared.h"
 #include "os/os.h"
diff --git a/fio_time.h b/fio_time.h
index 8b4bb255f0..39fb17ba24 100644
--- a/fio_time.h
+++ b/fio_time.h
@@ -1,6 +1,7 @@
 #ifndef FIO_TIME_H
 #define FIO_TIME_H
 
+#include <stdint.h>
 #include <time.h>
 #include <sys/time.h>
 #include "lib/types.h"
diff --git a/gettime-thread.c b/gettime-thread.c
index 87f50600cc..eb535a07cf 100644
--- a/gettime-thread.c
+++ b/gettime-thread.c
@@ -1,5 +1,3 @@
-#include <unistd.h>
-#include <math.h>
 #include <sys/time.h>
 #include <time.h>
 
diff --git a/gettime.c b/gettime.c
index 57c66f7e6f..87fc29b501 100644
--- a/gettime.c
+++ b/gettime.c
@@ -2,16 +2,9 @@
  * Clock functions
  */
 
-#include <unistd.h>
 #include <math.h>
-#include <sys/time.h>
-#include <time.h>
 
 #include "fio.h"
-#include "fio_sem.h"
-#include "smalloc.h"
-
-#include "hash.h"
 #include "os/os.h"
 
 #if defined(ARCH_HAVE_CPU_CLOCK)
diff --git a/gettime.h b/gettime.h
index 11e2a7b9c2..1c4a25c877 100644
--- a/gettime.h
+++ b/gettime.h
@@ -1,6 +1,8 @@
 #ifndef FIO_GETTIME_H
 #define FIO_GETTIME_H
 
+#include <sys/time.h>
+
 #include "arch/arch.h"
 
 /*
diff --git a/helpers.c b/helpers.c
index 4342b2d2fa..a0ee37044e 100644
--- a/helpers.c
+++ b/helpers.c
@@ -1,13 +1,6 @@
-#include <stdlib.h>
 #include <errno.h>
-#include <sys/socket.h>
-#include <sys/time.h>
-#include <netinet/in.h>
-#include <unistd.h>
 
-#include "compiler/compiler.h"
-#include "arch/arch.h"
-#include "os/os.h"
+#include "helpers.h"
 
 #ifndef CONFIG_LINUX_FALLOCATE
 int fallocate(int fd, int mode, off_t offset, off_t len)
diff --git a/helpers.h b/helpers.h
index 5f1865bba8..a0b328581f 100644
--- a/helpers.h
+++ b/helpers.h
@@ -1,10 +1,9 @@
 #ifndef FIO_HELPERS_H
 #define FIO_HELPERS_H
 
-#include "compiler/compiler.h"
-
 #include <sys/types.h>
-#include <time.h>
+
+#include "os/os.h"
 
 extern int fallocate(int fd, int mode, off_t offset, off_t len);
 extern int posix_fallocate(int fd, off_t offset, off_t len);
diff --git a/idletime.c b/idletime.c
index 90bc1d9eb0..8762c8565e 100644
--- a/idletime.c
+++ b/idletime.c
@@ -1,4 +1,5 @@
 #include <math.h>
+#include "fio.h"
 #include "json.h"
 #include "idletime.h"
 
diff --git a/idletime.h b/idletime.h
index b8376c2ce6..6c1161a7c2 100644
--- a/idletime.h
+++ b/idletime.h
@@ -1,8 +1,9 @@
 #ifndef FIO_IDLETIME_H
 #define FIO_IDLETIME_H
 
-#include "fio.h"
-#include "lib/output_buffer.h"
+#include <sys/time.h>
+#include <sys/types.h>
+#include "os/os.h"
 
 #define CALIBRATE_RUNS  10
 #define CALIBRATE_SCALE 1000
diff --git a/init.c b/init.c
index e47e538411..ab7e399752 100644
--- a/init.c
+++ b/init.c
@@ -4,13 +4,11 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
-#include <fcntl.h>
 #include <ctype.h>
 #include <string.h>
 #include <errno.h>
 #include <sys/ipc.h>
 #include <sys/types.h>
-#include <sys/stat.h>
 #include <dlfcn.h>
 #ifdef CONFIG_VALGRIND_DEV
 #include <valgrind/drd.h>
diff --git a/io_u.c b/io_u.c
index f3b5932270..98a7dc5606 100644
--- a/io_u.c
+++ b/io_u.c
@@ -1,12 +1,8 @@
 #include <unistd.h>
-#include <fcntl.h>
 #include <string.h>
-#include <signal.h>
-#include <time.h>
 #include <assert.h>
 
 #include "fio.h"
-#include "hash.h"
 #include "verify.h"
 #include "trim.h"
 #include "lib/rand.h"
diff --git a/io_u.h b/io_u.h
index da25efb90b..aaa7d9723e 100644
--- a/io_u.h
+++ b/io_u.h
@@ -3,7 +3,6 @@
 
 #include "compiler/compiler.h"
 #include "os/os.h"
-#include "log.h"
 #include "io_ddir.h"
 #include "debug.h"
 #include "file.h"
diff --git a/io_u_queue.h b/io_u_queue.h
index b5b8d2faf3..545e2c41fa 100644
--- a/io_u_queue.h
+++ b/io_u_queue.h
@@ -2,6 +2,8 @@
 #define FIO_IO_U_QUEUE
 
 #include <assert.h>
+#include <stddef.h>
+
 #include "lib/types.h"
 
 struct io_u;
diff --git a/ioengines.c b/ioengines.c
index 965581aa41..a8ec79de47 100644
--- a/ioengines.c
+++ b/ioengines.c
@@ -9,7 +9,6 @@
  * generic io engine that could be used for other projects.
  *
  */
-#include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <string.h>
diff --git a/ioengines.h b/ioengines.h
index 32b18edadf..a0674aeabe 100644
--- a/ioengines.h
+++ b/ioengines.h
@@ -1,9 +1,10 @@
 #ifndef FIO_IOENGINE_H
 #define FIO_IOENGINE_H
 
+#include <stddef.h>
+
 #include "compiler/compiler.h"
-#include "os/os.h"
-#include "file.h"
+#include "flist.h"
 #include "io_u.h"
 
 #define FIO_IOOPS_VERSION	23
diff --git a/iolog.c b/iolog.c
index 460d7a2e51..2b5eaf0c52 100644
--- a/iolog.c
+++ b/iolog.c
@@ -4,7 +4,6 @@
  */
 #include <stdio.h>
 #include <stdlib.h>
-#include <libgen.h>
 #include <assert.h>
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -15,7 +14,6 @@
 
 #include "flist.h"
 #include "fio.h"
-#include "verify.h"
 #include "trim.h"
 #include "filelock.h"
 #include "smalloc.h"
diff --git a/iolog.h b/iolog.h
index 70981f99de..f70eb61e6e 100644
--- a/iolog.h
+++ b/iolog.h
@@ -1,6 +1,8 @@
 #ifndef FIO_IOLOG_H
 #define FIO_IOLOG_H
 
+#include <stdio.h>
+
 #include "lib/rbtree.h"
 #include "lib/ieee754.h"
 #include "flist.h"
diff --git a/json.c b/json.c
index e0227ec644..75212c8552 100644
--- a/json.c
+++ b/json.c
@@ -1,6 +1,5 @@
 #include <stdlib.h>
 #include <string.h>
-#include <stdio.h>
 #include <errno.h>
 #include <stdarg.h>
 #include "json.h"
diff --git a/json.h b/json.h
index d7017e0662..bcc712cd4d 100644
--- a/json.h
+++ b/json.h
@@ -3,10 +3,6 @@
 
 #include "lib/output_buffer.h"
 
-struct json_object;
-struct json_array;
-struct json_pair;
-
 #define JSON_TYPE_STRING 0
 #define JSON_TYPE_INTEGER 1
 #define JSON_TYPE_FLOAT 2
diff --git a/lib/bloom.c b/lib/bloom.c
index bb81dbbdf8..f4f9b6b9ee 100644
--- a/lib/bloom.c
+++ b/lib/bloom.c
@@ -1,9 +1,7 @@
 #include <stdlib.h>
-#include <inttypes.h>
 
 #include "bloom.h"
 #include "../hash.h"
-#include "../minmax.h"
 #include "../crc/xxhash.h"
 #include "../crc/murmur3.h"
 #include "../crc/crc32c.h"
diff --git a/lib/gauss.c b/lib/gauss.c
index f974490f72..1d24e187ab 100644
--- a/lib/gauss.c
+++ b/lib/gauss.c
@@ -1,6 +1,5 @@
 #include <math.h>
 #include <string.h>
-#include <stdio.h>
 #include "../hash.h"
 #include "gauss.h"
 
diff --git a/lib/ieee754.c b/lib/ieee754.c
index c7742a2d29..2154065cc1 100644
--- a/lib/ieee754.c
+++ b/lib/ieee754.c
@@ -5,7 +5,6 @@
  *
  * Below code was granted to the public domain.
  */
-#include <inttypes.h>
 #include "ieee754.h"
 
 uint64_t pack754(long double f, unsigned bits, unsigned expbits)
diff --git a/lib/lfsr.c b/lib/lfsr.c
index 0c0072ccb3..a4f1fb13b6 100644
--- a/lib/lfsr.c
+++ b/lib/lfsr.c
@@ -1,5 +1,4 @@
 #include <stdio.h>
-#include <math.h>
 
 #include "lfsr.h"
 #include "../compiler/compiler.h"
diff --git a/lib/memalign.c b/lib/memalign.c
index bfbd1e80c8..e774c19c3e 100644
--- a/lib/memalign.c
+++ b/lib/memalign.c
@@ -1,6 +1,5 @@
-#include <stdlib.h>
 #include <assert.h>
-#include <inttypes.h>
+#include <stdlib.h>
 
 #include "memalign.h"
 
diff --git a/lib/memalign.h b/lib/memalign.h
index df412e283a..c2eb17027d 100644
--- a/lib/memalign.h
+++ b/lib/memalign.h
@@ -1,6 +1,8 @@
 #ifndef FIO_MEMALIGN_H
 #define FIO_MEMALIGN_H
 
+#include <inttypes.h>
+
 extern void *fio_memalign(size_t alignment, size_t size);
 extern void fio_memfree(void *ptr, size_t size);
 
diff --git a/lib/memcpy.c b/lib/memcpy.c
index 00e65aa7d5..cf8572e270 100644
--- a/lib/memcpy.c
+++ b/lib/memcpy.c
@@ -1,3 +1,4 @@
+#include <inttypes.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -6,7 +7,7 @@
 #include "rand.h"
 #include "../fio_time.h"
 #include "../gettime.h"
-#include "../fio.h"
+#include "../os/os.h"
 
 #define BUF_SIZE	32 * 1024 * 1024ULL
 
diff --git a/lib/num2str.c b/lib/num2str.c
index 8d0884132f..387c5d7b32 100644
--- a/lib/num2str.c
+++ b/lib/num2str.c
@@ -1,3 +1,4 @@
+#include <assert.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
diff --git a/lib/output_buffer.c b/lib/output_buffer.c
index f6c304bdf0..beb8a1426a 100644
--- a/lib/output_buffer.c
+++ b/lib/output_buffer.c
@@ -1,4 +1,3 @@
-#include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
 
diff --git a/lib/output_buffer.h b/lib/output_buffer.h
index a235af2073..389ed5b7bc 100644
--- a/lib/output_buffer.h
+++ b/lib/output_buffer.h
@@ -1,7 +1,7 @@
 #ifndef FIO_OUTPUT_BUFFER_H
 #define FIO_OUTPUT_BUFFER_H
 
-#include <unistd.h>
+#include <stddef.h>
 
 struct buf_output {
 	char *buf;
diff --git a/lib/pattern.c b/lib/pattern.c
index 31ee4eaf98..2024f2e9cf 100644
--- a/lib/pattern.c
+++ b/lib/pattern.c
@@ -4,8 +4,6 @@
 #include <limits.h>
 #include <errno.h>
 #include <assert.h>
-#include <sys/types.h>
-#include <sys/stat.h>
 #include <fcntl.h>
 #include <unistd.h>
 
diff --git a/lib/pattern.h b/lib/pattern.h
index 9f937f0216..2d655ad0d0 100644
--- a/lib/pattern.h
+++ b/lib/pattern.h
@@ -1,8 +1,6 @@
 #ifndef FIO_PARSE_PATTERN_H
 #define FIO_PARSE_PATTERN_H
 
-struct pattern_fmt;
-
 /**
  * Pattern format description. The input for 'parse_pattern'.
  * Describes format with its name and callback, which should
diff --git a/lib/prio_tree.c b/lib/prio_tree.c
index de3fe1c025..d8e1b89a94 100644
--- a/lib/prio_tree.c
+++ b/lib/prio_tree.c
@@ -11,6 +11,7 @@
  * 02Feb2004	Initial version
  */
 
+#include <assert.h>
 #include <stdlib.h>
 #include <limits.h>
 
diff --git a/lib/prio_tree.h b/lib/prio_tree.h
index e1491dbd56..9bd458f1b6 100644
--- a/lib/prio_tree.h
+++ b/lib/prio_tree.h
@@ -2,7 +2,6 @@
 #define _LINUX_PRIO_TREE_H
 
 #include <inttypes.h>
-#include "../hash.h"
 
 struct prio_tree_node {
 	struct prio_tree_node	*left;
diff --git a/lib/rand.c b/lib/rand.c
index 3f60a67ab7..46ffe4fb0c 100644
--- a/lib/rand.c
+++ b/lib/rand.c
@@ -34,7 +34,6 @@
 */
 
 #include <string.h>
-#include <assert.h>
 #include "rand.h"
 #include "pattern.h"
 #include "../hash.h"
diff --git a/lib/rand.h b/lib/rand.h
index bff4a35167..8832c73a76 100644
--- a/lib/rand.h
+++ b/lib/rand.h
@@ -4,7 +4,6 @@
 #include <inttypes.h>
 #include <assert.h>
 #include "types.h"
-#include "../arch/arch.h"
 
 #define FRAND32_MAX	(-1U)
 #define FRAND64_MAX	(-1ULL)
diff --git a/lib/strntol.h b/lib/strntol.h
index 68f5d1b7db..59c090d3de 100644
--- a/lib/strntol.h
+++ b/lib/strntol.h
@@ -1,6 +1,8 @@
 #ifndef FIO_STRNTOL_H
 #define FIO_STRNTOL_H
 
+#include <stdint.h>
+
 long strntol(const char *str, size_t sz, char **end, int base);
 
 #endif
diff --git a/lib/zipf.c b/lib/zipf.c
index 3d535c79d3..1ff8568094 100644
--- a/lib/zipf.c
+++ b/lib/zipf.c
@@ -1,11 +1,5 @@
 #include <math.h>
 #include <string.h>
-#include <inttypes.h>
-#include <stdio.h>
-#include <unistd.h>
-#include <sys/types.h>
-#include <fcntl.h>
-#include "ieee754.h"
 #include "zipf.h"
 #include "../minmax.h"
 #include "../hash.h"
diff --git a/lib/zipf.h b/lib/zipf.h
index af2d0e645c..a4aa163c80 100644
--- a/lib/zipf.h
+++ b/lib/zipf.h
@@ -3,6 +3,7 @@
 
 #include <inttypes.h>
 #include "rand.h"
+#include "types.h"
 
 struct zipf_state {
 	uint64_t nranges;
diff --git a/libfio.c b/libfio.c
index 80159b4d0d..6faf32a4e9 100644
--- a/libfio.c
+++ b/libfio.c
@@ -23,7 +23,6 @@
  */
 
 #include <string.h>
-#include <sys/types.h>
 #include <signal.h>
 #include <stdint.h>
 #include <locale.h>
diff --git a/log.c b/log.c
index 7e8b13b31a..46e5034e3d 100644
--- a/log.c
+++ b/log.c
@@ -1,5 +1,4 @@
 #include <unistd.h>
-#include <fcntl.h>
 #include <string.h>
 #include <stdarg.h>
 #include <syslog.h>
diff --git a/memory.c b/memory.c
index 04dc3be8bf..5f0225f710 100644
--- a/memory.c
+++ b/memory.c
@@ -1,11 +1,10 @@
 /*
  * Memory helpers
  */
-#include <sys/types.h>
-#include <sys/stat.h>
 #include <fcntl.h>
 #include <unistd.h>
 #include <sys/mman.h>
+#include <sys/stat.h>
 
 #include "fio.h"
 #ifndef FIO_NO_HAVE_SHM_H
diff --git a/options.c b/options.c
index 681052127b..45a5b82be4 100644
--- a/options.c
+++ b/options.c
@@ -4,16 +4,12 @@
 #include <ctype.h>
 #include <string.h>
 #include <assert.h>
-#include <libgen.h>
-#include <fcntl.h>
-#include <sys/types.h>
 #include <sys/stat.h>
 #include <netinet/in.h>
 
 #include "fio.h"
 #include "verify.h"
 #include "parse.h"
-#include "lib/fls.h"
 #include "lib/pattern.h"
 #include "options.h"
 #include "optgroup.h"
diff --git a/options.h b/options.h
index 83a58e27d5..59024efc8a 100644
--- a/options.h
+++ b/options.h
@@ -6,7 +6,6 @@
 #include <string.h>
 #include <inttypes.h>
 #include "parse.h"
-#include "flist.h"
 #include "lib/types.h"
 
 int add_option(struct fio_option *);
diff --git a/oslib/strlcat.h b/oslib/strlcat.h
index baeace40d4..720034fe72 100644
--- a/oslib/strlcat.h
+++ b/oslib/strlcat.h
@@ -1,6 +1,8 @@
 #ifndef FIO_STRLCAT_H
 #define FIO_STRLCAT_H
 
+#include <stddef.h>
+
 size_t strlcat(char *dst, const char *src, size_t size);
 
 #endif
diff --git a/oslib/strndup.c b/oslib/strndup.c
index 7b0fcb5161..40e92f820d 100644
--- a/oslib/strndup.c
+++ b/oslib/strndup.c
@@ -1,4 +1,5 @@
 #include <stdlib.h>
+
 #include "strndup.h"
 
 #ifndef CONFIG_HAVE_STRNDUP
diff --git a/parse.c b/parse.c
index fdb66115c3..33fcf465ca 100644
--- a/parse.c
+++ b/parse.c
@@ -3,18 +3,16 @@
  */
 #include <stdio.h>
 #include <stdlib.h>
-#include <unistd.h>
 #include <ctype.h>
 #include <string.h>
 #include <errno.h>
 #include <limits.h>
-#include <stdlib.h>
-#include <math.h>
 #include <float.h>
 
 #include "compiler/compiler.h"
 #include "parse.h"
 #include "debug.h"
+#include "log.h"
 #include "options.h"
 #include "optgroup.h"
 #include "minmax.h"
diff --git a/server.c b/server.c
index 65d4484eda..6f85810963 100644
--- a/server.c
+++ b/server.c
@@ -1,8 +1,6 @@
 #include <stdio.h>
 #include <stdlib.h>
-#include <stdarg.h>
 #include <unistd.h>
-#include <limits.h>
 #include <errno.h>
 #include <sys/poll.h>
 #include <sys/types.h>
@@ -25,7 +23,7 @@
 #include "server.h"
 #include "crc/crc16.h"
 #include "lib/ieee754.h"
-#include "verify.h"
+#include "verify-state.h"
 #include "smalloc.h"
 
 int fio_net_port = FIO_NET_PORT;
diff --git a/server.h b/server.h
index d652d31cf8..1eee7dcf97 100644
--- a/server.h
+++ b/server.h
@@ -7,7 +7,6 @@
 #include <netinet/in.h>
 
 #include "stat.h"
-#include "os/os.h"
 #include "diskutil.h"
 
 #define FIO_NET_PORT 8765
@@ -217,8 +216,6 @@ extern int fio_server_parse_host(const char *, int, struct in_addr *, struct in6
 extern const char *fio_server_op(unsigned int);
 extern void fio_server_got_signal(int);
 
-struct thread_stat;
-struct group_run_stats;
 extern void fio_server_send_ts(struct thread_stat *, struct group_run_stats *);
 extern void fio_server_send_gs(struct group_run_stats *);
 extern void fio_server_send_du(void);
diff --git a/smalloc.c b/smalloc.c
index 13995acce0..7b1690ada9 100644
--- a/smalloc.c
+++ b/smalloc.c
@@ -3,15 +3,8 @@
  * that can be shared across processes and threads
  */
 #include <sys/mman.h>
-#include <stdio.h>
-#include <stdlib.h>
 #include <assert.h>
 #include <string.h>
-#include <unistd.h>
-#include <inttypes.h>
-#include <sys/types.h>
-#include <limits.h>
-#include <fcntl.h>
 #ifdef CONFIG_VALGRIND_DEV
 #include <valgrind/valgrind.h>
 #else
@@ -22,7 +15,6 @@
 
 #include "fio.h"
 #include "fio_sem.h"
-#include "arch/arch.h"
 #include "os/os.h"
 #include "smalloc.h"
 #include "log.h"
diff --git a/smalloc.h b/smalloc.h
index 4b551e3e4b..8df10e6f67 100644
--- a/smalloc.h
+++ b/smalloc.h
@@ -1,6 +1,8 @@
 #ifndef FIO_SMALLOC_H
 #define FIO_SMALLOC_H
 
+#include <stddef.h>
+
 extern void *smalloc(size_t);
 extern void *scalloc(size_t, size_t);
 extern void sfree(void *);
diff --git a/stat.c b/stat.c
index 98ab638939..a837ed9025 100644
--- a/stat.c
+++ b/stat.c
@@ -1,10 +1,7 @@
 #include <stdio.h>
 #include <string.h>
 #include <sys/time.h>
-#include <sys/types.h>
 #include <sys/stat.h>
-#include <dirent.h>
-#include <libgen.h>
 #include <math.h>
 
 #include "fio.h"
diff --git a/steadystate.c b/steadystate.c
index 2017ca67a8..1e3a546896 100644
--- a/steadystate.c
+++ b/steadystate.c
@@ -2,7 +2,6 @@
 
 #include "fio.h"
 #include "steadystate.h"
-#include "helper_thread.h"
 
 bool steadystate_enabled = false;
 
diff --git a/steadystate.h b/steadystate.h
index 9fd88ee8ce..51472c4698 100644
--- a/steadystate.h
+++ b/steadystate.h
@@ -1,9 +1,7 @@
 #ifndef FIO_STEADYSTATE_H
 #define FIO_STEADYSTATE_H
 
-#include "stat.h"
 #include "thread_options.h"
-#include "lib/ieee754.h"
 
 extern void steadystate_free(struct thread_data *);
 extern void steadystate_check(void);
diff --git a/t/axmap.c b/t/axmap.c
index a803ce47bf..eef464ff2d 100644
--- a/t/axmap.c
+++ b/t/axmap.c
@@ -1,8 +1,5 @@
 #include <stdio.h>
 #include <stdlib.h>
-#include <fcntl.h>
-#include <string.h>
-#include <unistd.h>
 #include <inttypes.h>
 
 #include "../lib/lfsr.h"
diff --git a/t/btrace2fio.c b/t/btrace2fio.c
index 4cdb38d10d..a8a9d62914 100644
--- a/t/btrace2fio.c
+++ b/t/btrace2fio.c
@@ -1,5 +1,4 @@
 #include <stdio.h>
-#include <stdio.h>
 #include <unistd.h>
 #include <inttypes.h>
 #include <math.h>
@@ -12,6 +11,7 @@
 #include "../blktrace_api.h"
 #include "../os/os.h"
 #include "../log.h"
+#include "../minmax.h"
 #include "../oslib/linux-dev-lookup.h"
 
 #define TRACE_FIFO_SIZE	8192
diff --git a/t/dedupe.c b/t/dedupe.c
index 1b4277c1b9..37120e1895 100644
--- a/t/dedupe.c
+++ b/t/dedupe.c
@@ -3,16 +3,12 @@
  * just scans the filename for extents of the given size, checksums them,
  * and orders them up.
  */
+#include <fcntl.h>
+#include <inttypes.h>
 #include <stdio.h>
-#include <stdio.h>
+#include <string.h>
 #include <unistd.h>
-#include <inttypes.h>
-#include <assert.h>
-#include <sys/types.h>
 #include <sys/stat.h>
-#include <sys/ioctl.h>
-#include <fcntl.h>
-#include <string.h>
 
 #include "../flist.h"
 #include "../log.h"
diff --git a/t/gen-rand.c b/t/gen-rand.c
index 4e9d39c643..c379053db6 100644
--- a/t/gen-rand.c
+++ b/t/gen-rand.c
@@ -1,17 +1,11 @@
+#include <math.h>
+#include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <inttypes.h>
-#include <assert.h>
-#include <math.h>
-#include <string.h>
 
 #include "../lib/types.h"
-#include "../log.h"
-#include "../lib/lfsr.h"
-#include "../lib/axmap.h"
-#include "../smalloc.h"
-#include "../minmax.h"
 #include "../lib/rand.h"
+#include "../log.h"
 
 int main(int argc, char *argv[])
 {
diff --git a/t/genzipf.c b/t/genzipf.c
index 9faec38934..4fc10ae72d 100644
--- a/t/genzipf.c
+++ b/t/genzipf.c
@@ -14,7 +14,6 @@
  */
 #include <stdio.h>
 #include <stdlib.h>
-#include <fcntl.h>
 #include <string.h>
 #include <unistd.h>
 
diff --git a/t/lfsr-test.c b/t/lfsr-test.c
index 4009b62e38..abdbafb599 100644
--- a/t/lfsr-test.c
+++ b/t/lfsr-test.c
@@ -1,11 +1,7 @@
 #include <stdio.h>
 #include <stdlib.h>
-#include <time.h>
 #include <math.h>
 #include <string.h>
-#include <unistd.h>
-#include <sys/types.h>
-#include <sys/stat.h>
 
 #include "../lib/lfsr.h"
 #include "../gettime.h"
diff --git a/td_error.h b/td_error.h
index 1b38a5349f..1cc3a75390 100644
--- a/td_error.h
+++ b/td_error.h
@@ -1,6 +1,8 @@
 #ifndef FIO_TD_ERROR_H
 #define FIO_TD_ERROR_H
 
+#include "io_ddir.h"
+
 /*
  * What type of errors to continue on when continue_on_error is used,
  * and what type of errors to ignore when ignore_error is used.
diff --git a/trim.c b/trim.c
index 78cf67244e..bf825db346 100644
--- a/trim.c
+++ b/trim.c
@@ -1,11 +1,8 @@
 /*
  * TRIM/DISCARD support
  */
-#include <unistd.h>
-#include <fcntl.h>
 #include <string.h>
 #include <assert.h>
-#include <pthread.h>
 
 #include "fio.h"
 #include "trim.h"
diff --git a/trim.h b/trim.h
index 37f5d7c871..fe8f9fe990 100644
--- a/trim.h
+++ b/trim.h
@@ -1,9 +1,13 @@
 #ifndef FIO_TRIM_H
 #define FIO_TRIM_H
 
-#include "fio.h"
-
 #ifdef FIO_HAVE_TRIM
+#include "flist.h"
+#include "iolog.h"
+#include "compiler/compiler.h"
+#include "lib/types.h"
+#include "os/os.h"
+
 extern bool __must_check get_next_trim(struct thread_data *td, struct io_u *io_u);
 extern bool io_u_should_trim(struct thread_data *td, struct io_u *io_u);
 
diff --git a/verify.h b/verify.h
index 321e6485e6..64121a51af 100644
--- a/verify.h
+++ b/verify.h
@@ -2,6 +2,7 @@
 #define FIO_VERIFY_H
 
 #include <stdint.h>
+#include "compiler/compiler.h"
 #include "verify-state.h"
 
 #define FIO_HDR_MAGIC	0xacca
diff --git a/workqueue.h b/workqueue.h
index e35c181a23..0a62b5f7d3 100644
--- a/workqueue.h
+++ b/workqueue.h
@@ -1,7 +1,14 @@
 #ifndef FIO_RATE_H
 #define FIO_RATE_H
 
+#include <inttypes.h>
+#include <pthread.h>
+
 #include "flist.h"
+#include "lib/types.h"
+
+struct sk_out;
+struct thread_data;
 
 struct workqueue_work {
 	struct flist_head list;