Fix: use "flush empty" ioctl for snapshots

[lttng-tools.git] / src / common / kernel-ctl / kernel-ioctl.h

diff --git a/src/common/kernel-ctl/kernel-ioctl.h b/src/common/kernel-ctl/kernel-ioctl.h
index f5e866b8832213d16b3516b38e757684d23eb580..cddea3fc44a021925128e37d8d0280e6be8bf21a 100644 (file)
--- a/src/common/kernel-ctl/kernel-ioctl.h
+++ b/src/common/kernel-ctl/kernel-ioctl.h
@@ -20,7 +20,7 @@
 #define _LTT_KERNEL_IOCTL_H
 
 #define LTTNG_MODULES_ABI_MAJOR_VERSION                2
-#define LTTNG_MODULES_ABI_MINOR_VERSION                0
+#define LTTNG_MODULES_ABI_MINOR_VERSION                1
 
 /* Get a snapshot of the current ring buffer producer and consumer positions */
 #define RING_BUFFER_SNAPSHOT                _IO(0xF6, 0x00)
@@ -47,10 +47,12 @@
 #define RING_BUFFER_GET_MMAP_LEN            _IOR(0xF6, 0x0A, unsigned long)
 /* returns the offset of the subbuffer belonging to the mmap reader. */
 #define RING_BUFFER_GET_MMAP_READ_OFFSET    _IOR(0xF6, 0x0B, unsigned long)
-/* flush the current sub-buffer */
+/* Flush the current sub-buffer, if non-empty. */
 #define RING_BUFFER_FLUSH                   _IO(0xF6, 0x0C)
 /* Get the current version of the metadata cache (after a get_next). */
 #define RING_BUFFER_GET_METADATA_VERSION    _IOR(0xF6, 0x0D, uint64_t)
+/* Flush the current sub-buffer, even if empty. */
+#define RING_BUFFER_FLUSH_EMPTY                        _IO(0xF6, 0x0F)
 
 /* returns the timestamp begin of the current sub-buffer */
 #define LTTNG_RING_BUFFER_GET_TIMESTAMP_BEGIN     _IOR(0xF6, 0x20, uint64_t)
@@ -127,6 +129,11 @@
        _IOR(0xF6, 0x58, int32_t)
 #define LTTNG_KERNEL_SESSION_UNTRACK_PID       \
        _IOR(0xF6, 0x59, int32_t)
+/*
+ * ioctl 0x58 and 0x59 are duplicated here. It works, since _IOR vs _IO
+ * are generating two different ioctl numbers, but this was not done on
+ * purpose. We should generally try to avoid those duplications.
+ */
 #define LTTNG_KERNEL_SESSION_LIST_TRACKER_PIDS _IO(0xF6, 0x58)
 #define LTTNG_KERNEL_SESSION_METADATA_REGEN    _IO(0xF6, 0x59)