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authorAlexander Aring <aahringo@redhat.com>2021-11-02 22:17:15 +0300
committerDavid Teigland <teigland@redhat.com>2021-11-02 22:39:20 +0300
commitf1d3b8f91d965c4fd900ac5dd06240cc9df0c7a7 (patch)
tree5457b9004b866a1e7ffeb57ff011db5a5f353d81 /fs/dlm
parent2f05ec4327ffaa34877de67fc5bb5eb3ab3767f0 (diff)
downloadlinux-f1d3b8f91d965c4fd900ac5dd06240cc9df0c7a7.tar.xz
fs: dlm: initial support for tracepoints
This patch adds initial support for dlm tracepoints. It will introduce tracepoints to dlm main functionality dlm_lock()/dlm_unlock() and their complete ast() callback or blocking bast() callback. The lock/unlock functionality has a start and end tracepoint, this is because there exists a race in case if would have a tracepoint at the end position only the complete/blocking callbacks could occur before. To work with eBPF tracing and using their lookup hash functionality there could be problems that an entry was not inserted yet. However use the start functionality for hash insert and check again in end functionality if there was an dlm internal error so there is no ast callback. In further it might also that locks with local masters will occur those callbacks immediately so we must have such functionality. I did not make everything accessible yet, although it seems eBPF can be used to access a lot of internal datastructures if it's aware of the struct definitions of the running kernel instance. We still can change it, if you do eBPF experiments e.g. time measurements between lock and callback functionality you can simple use the local lkb_id field as hash value in combination with the lockspace id if you have multiple lockspaces. Otherwise you can simple use trace-cmd for some functionality, e.g. `trace-cmd record -e dlm` and `trace-cmd report` afterwards. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
Diffstat (limited to 'fs/dlm')
-rw-r--r--fs/dlm/ast.c4
-rw-r--r--fs/dlm/lock.c10
-rw-r--r--fs/dlm/main.c3
3 files changed, 17 insertions, 0 deletions
diff --git a/fs/dlm/ast.c b/fs/dlm/ast.c
index 6600930497cc..27bae7d4a477 100644
--- a/fs/dlm/ast.c
+++ b/fs/dlm/ast.c
@@ -9,6 +9,8 @@
*******************************************************************************
******************************************************************************/
+#include <trace/events/dlm.h>
+
#include "dlm_internal.h"
#include "lock.h"
#include "user.h"
@@ -254,10 +256,12 @@ void dlm_callback_work(struct work_struct *work)
continue;
} else if (callbacks[i].flags & DLM_CB_BAST) {
bastfn(lkb->lkb_astparam, callbacks[i].mode);
+ trace_dlm_bast(ls, lkb, callbacks[i].mode);
} else if (callbacks[i].flags & DLM_CB_CAST) {
lkb->lkb_lksb->sb_status = callbacks[i].sb_status;
lkb->lkb_lksb->sb_flags = callbacks[i].sb_flags;
castfn(lkb->lkb_astparam);
+ trace_dlm_ast(ls, lkb, lkb->lkb_lksb);
}
}
diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index c502c065d007..feb2e94f5879 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -53,6 +53,8 @@
R: do_xxxx()
L: receive_xxxx_reply() <- R: send_xxxx_reply()
*/
+#include <trace/events/dlm.h>
+
#include <linux/types.h>
#include <linux/rbtree.h>
#include <linux/slab.h>
@@ -3437,6 +3439,8 @@ int dlm_lock(dlm_lockspace_t *lockspace,
if (error)
goto out;
+ trace_dlm_lock_start(ls, lkb, mode, flags);
+
error = set_lock_args(mode, lksb, flags, namelen, 0, ast,
astarg, bast, &args);
if (error)
@@ -3450,6 +3454,8 @@ int dlm_lock(dlm_lockspace_t *lockspace,
if (error == -EINPROGRESS)
error = 0;
out_put:
+ trace_dlm_lock_end(ls, lkb, mode, flags, error);
+
if (convert || error)
__put_lkb(ls, lkb);
if (error == -EAGAIN || error == -EDEADLK)
@@ -3481,6 +3487,8 @@ int dlm_unlock(dlm_lockspace_t *lockspace,
if (error)
goto out;
+ trace_dlm_unlock_start(ls, lkb, flags);
+
error = set_unlock_args(flags, astarg, &args);
if (error)
goto out_put;
@@ -3495,6 +3503,8 @@ int dlm_unlock(dlm_lockspace_t *lockspace,
if (error == -EBUSY && (flags & (DLM_LKF_CANCEL | DLM_LKF_FORCEUNLOCK)))
error = 0;
out_put:
+ trace_dlm_unlock_end(ls, lkb, flags, error);
+
dlm_put_lkb(lkb);
out:
dlm_unlock_recovery(ls);
diff --git a/fs/dlm/main.c b/fs/dlm/main.c
index afc66a1346d3..1c5be4b70ac1 100644
--- a/fs/dlm/main.c
+++ b/fs/dlm/main.c
@@ -19,6 +19,9 @@
#include "config.h"
#include "lowcomms.h"
+#define CREATE_TRACE_POINTS
+#include <trace/events/dlm.h>
+
static int __init init_dlm(void)
{
int error;