[v3] perf: Convert mmap() related reference counts to refcount_t

[PATCH v3 03/15] perf: Split out VM accounting

Posted by Peter Zijlstra 1 month, 3 weeks ago

From: Thomas Gleixner <tglx@linutronix.de>

Similary to the mlock limit calculation the VM accounting is required for
both the ringbuffer and the AUX buffer allocations.

To prepare for splitting them out into seperate functions, move the
accounting into a helper function.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Link: https://lkml.kernel.org/r/20250811070620.527392167@linutronix.de
---
 kernel/events/core.c |   13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6962,10 +6962,17 @@ static bool perf_mmap_calc_limits(struct
 	return locked <= lock_limit || !perf_is_paranoid() || capable(CAP_IPC_LOCK);
 }
 
+static void perf_mmap_account(struct vm_area_struct *vma, long user_extra, long extra)
+{
+	struct user_struct *user = current_user();
+
+	atomic_long_add(user_extra, &user->locked_vm);
+	atomic64_add(extra, &vma->vm_mm->pinned_vm);
+}
+
 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
 {
 	struct perf_event *event = file->private_data;
-	struct user_struct *user = current_user();
 	unsigned long vma_size, nr_pages;
 	long user_extra = 0, extra = 0;
 	struct mutex *aux_mutex = NULL;
@@ -7136,9 +7143,7 @@ static int perf_mmap(struct file *file,
 
 unlock:
 	if (!ret) {
-		atomic_long_add(user_extra, &user->locked_vm);
-		atomic64_add(extra, &vma->vm_mm->pinned_vm);
-
+		perf_mmap_account(vma, user_extra, extra);
 		atomic_inc(&event->mmap_count);
 	} else if (rb) {
 		/* AUX allocation failed */

Re: [PATCH v3 03/15] perf: Split out VM accounting

Posted by Lorenzo Stoakes 1 month, 3 weeks ago

On Tue, Aug 12, 2025 at 12:39:01PM +0200, Peter Zijlstra wrote:
> From: Thomas Gleixner <tglx@linutronix.de>
>
> Similary to the mlock limit calculation the VM accounting is required for

NIT: Similary -> Similarly

> both the ringbuffer and the AUX buffer allocations.
>
> To prepare for splitting them out into seperate functions, move the

NIT: Seperate -> Separate

And that's the end of the typo nits ;)

> accounting into a helper function.
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> Link: https://lkml.kernel.org/r/20250811070620.527392167@linutronix.de
> ---
>  kernel/events/core.c |   13 +++++++++----
>  1 file changed, 9 insertions(+), 4 deletions(-)
>
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -6962,10 +6962,17 @@ static bool perf_mmap_calc_limits(struct
>  	return locked <= lock_limit || !perf_is_paranoid() || capable(CAP_IPC_LOCK);
>  }
>
> +static void perf_mmap_account(struct vm_area_struct *vma, long user_extra, long extra)
> +{
> +	struct user_struct *user = current_user();
> +
> +	atomic_long_add(user_extra, &user->locked_vm);
> +	atomic64_add(extra, &vma->vm_mm->pinned_vm);
> +}
> +
>  static int perf_mmap(struct file *file, struct vm_area_struct *vma)
>  {
>  	struct perf_event *event = file->private_data;
> -	struct user_struct *user = current_user();
>  	unsigned long vma_size, nr_pages;
>  	long user_extra = 0, extra = 0;
>  	struct mutex *aux_mutex = NULL;
> @@ -7136,9 +7143,7 @@ static int perf_mmap(struct file *file,
>
>  unlock:
>  	if (!ret) {
> -		atomic_long_add(user_extra, &user->locked_vm);
> -		atomic64_add(extra, &vma->vm_mm->pinned_vm);
> -
> +		perf_mmap_account(vma, user_extra, extra);
>  		atomic_inc(&event->mmap_count);
>  	} else if (rb) {
>  		/* AUX allocation failed */
>
>

[tip: perf/core] perf: Split out VM accounting

Posted by tip-bot2 for Thomas Gleixner 1 month, 2 weeks ago

The following commit has been merged into the perf/core branch of tip:

Commit-ID:     1ea3e3b0dadc06c5e6c1bdf5312e70ee861b1ba0
Gitweb:        https://git.kernel.org/tip/1ea3e3b0dadc06c5e6c1bdf5312e70ee861b1ba0
Author:        Thomas Gleixner <tglx@linutronix.de>
AuthorDate:    Tue, 12 Aug 2025 12:39:01 +02:00
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Fri, 15 Aug 2025 13:12:59 +02:00

perf: Split out VM accounting

Similarly to the mlock limit calculation the VM accounting is required for
both the ringbuffer and the AUX buffer allocations.

To prepare for splitting them out into separate functions, move the
accounting into a helper function.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Link: https://lore.kernel.org/r/20250812104018.660347811@infradead.org
---
 kernel/events/core.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index f629901..f908471 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6962,10 +6962,17 @@ static bool perf_mmap_calc_limits(struct vm_area_struct *vma, long *user_extra, 
 	return locked <= lock_limit || !perf_is_paranoid() || capable(CAP_IPC_LOCK);
 }
 
+static void perf_mmap_account(struct vm_area_struct *vma, long user_extra, long extra)
+{
+	struct user_struct *user = current_user();
+
+	atomic_long_add(user_extra, &user->locked_vm);
+	atomic64_add(extra, &vma->vm_mm->pinned_vm);
+}
+
 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
 {
 	struct perf_event *event = file->private_data;
-	struct user_struct *user = current_user();
 	unsigned long vma_size, nr_pages;
 	long user_extra = 0, extra = 0;
 	struct mutex *aux_mutex = NULL;
@@ -7136,9 +7143,7 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma)
 
 unlock:
 	if (!ret) {
-		atomic_long_add(user_extra, &user->locked_vm);
-		atomic64_add(extra, &vma->vm_mm->pinned_vm);
-
+		perf_mmap_account(vma, user_extra, extra);
 		atomic_inc(&event->mmap_count);
 	} else if (rb) {
 		/* AUX allocation failed */