From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Thu, 2 Nov 2023 02:15:42 +0000 (-1000)
Subject: Merge tag 'probes-v6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux... 
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=05bf73aa27ba89474763cea7b9cd2626eda61e01;p=linux.git

Merge tag 'probes-v6.7' of git://git./linux/kernel/git/trace/linux-trace

Pull probes updates from Masami Hiramatsu:
 "Cleanups:

   - kprobes: Fixes typo in kprobes samples

   - tracing/eprobes: Remove 'break' after return

  kretprobe/fprobe performance improvements:

   - lib: Introduce new `objpool`, which is a high performance lockless
     object queue. This uses per-cpu ring array to allocate/release
     objects from the pre-allocated object pool.

     Since the index of ring array is a 32bit sequential counter, we can
     retry to push/pop the object pointer from the ring without lock (as
     seq-lock does)

   - lib: Add an objpool test module to test the functionality and
     evaluate the performance under some circumstances

   - kprobes/fprobe: Improve kretprobe and rethook scalability
     performance with objpool.

     This improves both legacy kretprobe and fprobe exit handler (which
     is based on rethook) to be scalable on SMP systems. Even with
     8-threads parallel test, it shows a great scalability improvement

   - Remove unneeded freelist.h which is replaced by objpool

   - objpool: Add maintainers entry for the objpool

   - objpool: Fix to remove unused include header lines"

* tag 'probes-v6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  kprobes: unused header files removed
  MAINTAINERS: objpool added
  kprobes: freelist.h removed
  kprobes: kretprobe scalability improvement
  lib: objpool test module added
  lib: objpool added: ring-array based lockless MPMC
  tracing/eprobe: drop unneeded breaks
  samples: kprobes: Fixes a typo
---

05bf73aa27ba89474763cea7b9cd2626eda61e01
diff --cc kernel/trace/fprobe.c
index 881f90f0cbcfa,6890f4fd17fc8..6cd2a4e3afb8f
--- a/kernel/trace/fprobe.c
+++ b/kernel/trace/fprobe.c
@@@ -187,9 -187,9 +187,9 @@@ static void fprobe_init(struct fprobe *
  
  static int fprobe_init_rethook(struct fprobe *fp, int num)
  {
- 	int i, size;
+ 	int size;
  
 -	if (num < 0)
 +	if (num <= 0)
  		return -EINVAL;
  
  	if (!fp->exit_handler) {
@@@ -202,23 -202,15 +202,15 @@@
  		size = fp->nr_maxactive;
  	else
  		size = num * num_possible_cpus() * 2;
 -	if (size < 0)
 -		return -E2BIG;
 +	if (size <= 0)
 +		return -EINVAL;
  
- 	fp->rethook = rethook_alloc((void *)fp, fprobe_exit_handler);
- 	if (!fp->rethook)
- 		return -ENOMEM;
- 	for (i = 0; i < size; i++) {
- 		struct fprobe_rethook_node *node;
- 
- 		node = kzalloc(sizeof(*node) + fp->entry_data_size, GFP_KERNEL);
- 		if (!node) {
- 			rethook_free(fp->rethook);
- 			fp->rethook = NULL;
- 			return -ENOMEM;
- 		}
- 		rethook_add_node(fp->rethook, &node->node);
- 	}
+ 	/* Initialize rethook */
+ 	fp->rethook = rethook_alloc((void *)fp, fprobe_exit_handler,
+ 				sizeof(struct fprobe_rethook_node), size);
+ 	if (IS_ERR(fp->rethook))
+ 		return PTR_ERR(fp->rethook);
+ 
  	return 0;
  }