[PATCHv15,09/17] mm: Expose untagging mask in /proc/$PID/status
Commit Message
Add a line in /proc/$PID/status to report untag_mask. It can be
used to find out LAM status of the process from the outside. It is
useful for debuggers.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
arch/arm64/include/asm/mmu_context.h | 6 ++++++
arch/sparc/include/asm/mmu_context_64.h | 6 ++++++
arch/x86/include/asm/mmu_context.h | 6 ++++++
fs/proc/array.c | 6 ++++++
include/linux/mmu_context.h | 7 +++++++
5 files changed, 31 insertions(+)
Comments
On Mon, Jan 23, 2023 at 11:05 PM Kirill A. Shutemov
<kirill.shutemov@linux.intel.com> wrote:
>
> Add a line in /proc/$PID/status to report untag_mask. It can be
> used to find out LAM status of the process from the outside. It is
> useful for debuggers.
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Acked-by: Catalin Marinas <catalin.marinas@arm.com>
> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Alexander Potapenko <glider@google.com>
On Mon, Jan 23, 2023 at 11:05 PM Kirill A. Shutemov
<kirill.shutemov@linux.intel.com> wrote:
>
> Add a line in /proc/$PID/status to report untag_mask. It can be
> used to find out LAM status of the process from the outside. It is
> useful for debuggers.
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Acked-by: Catalin Marinas <catalin.marinas@arm.com>
> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> mm->context.untag_mask = -1UL;
> diff --git a/fs/proc/array.c b/fs/proc/array.c
> index 49283b8103c7..d2a94eafe9a3 100644
> --- a/fs/proc/array.c
> +++ b/fs/proc/array.c
Right now mm_untag_mask() is visible from array.c thanks to inclusion
of <linux/cpuset.h>, which happens to include <linux/mmu_context.h>.
But maybe it would be better to directly include mmu_context.h here?
@@ -288,6 +288,12 @@ void post_ttbr_update_workaround(void);
unsigned long arm64_mm_context_get(struct mm_struct *mm);
void arm64_mm_context_put(struct mm_struct *mm);
+#define mm_untag_mask mm_untag_mask
+static inline unsigned long mm_untag_mask(struct mm_struct *mm)
+{
+ return -1UL >> 8;
+}
+
#include <asm-generic/mmu_context.h>
#endif /* !__ASSEMBLY__ */
@@ -185,6 +185,12 @@ static inline void finish_arch_post_lock_switch(void)
}
}
+#define mm_untag_mask mm_untag_mask
+static inline unsigned long mm_untag_mask(struct mm_struct *mm)
+{
+ return -1UL >> adi_nbits();
+}
+
#include <asm-generic/mmu_context.h>
#endif /* !(__ASSEMBLY__) */
@@ -103,6 +103,12 @@ static inline void dup_lam(struct mm_struct *oldmm, struct mm_struct *mm)
mm->context.untag_mask = oldmm->context.untag_mask;
}
+#define mm_untag_mask mm_untag_mask
+static inline unsigned long mm_untag_mask(struct mm_struct *mm)
+{
+ return mm->context.untag_mask;
+}
+
static inline void mm_reset_untag_mask(struct mm_struct *mm)
{
mm->context.untag_mask = -1UL;
@@ -428,6 +428,11 @@ static inline void task_thp_status(struct seq_file *m, struct mm_struct *mm)
seq_printf(m, "THP_enabled:\t%d\n", thp_enabled);
}
+static inline void task_untag_mask(struct seq_file *m, struct mm_struct *mm)
+{
+ seq_printf(m, "untag_mask:\t%#lx\n", mm_untag_mask(mm));
+}
+
int proc_pid_status(struct seq_file *m, struct pid_namespace *ns,
struct pid *pid, struct task_struct *task)
{
@@ -443,6 +448,7 @@ int proc_pid_status(struct seq_file *m, struct pid_namespace *ns,
task_mem(m, mm);
task_core_dumping(m, task);
task_thp_status(m, mm);
+ task_untag_mask(m, mm);
mmput(mm);
}
task_sig(m, task);
@@ -28,4 +28,11 @@ static inline void leave_mm(int cpu) { }
# define task_cpu_possible(cpu, p) cpumask_test_cpu((cpu), task_cpu_possible_mask(p))
#endif
+#ifndef mm_untag_mask
+static inline unsigned long mm_untag_mask(struct mm_struct *mm)
+{
+ return -1UL;
+}
+#endif
+
#endif