[v5,05/13] xen/spinlock: make struct lock_profile rspinlock_t aware

Commit Message

Jürgen Groß March 14, 2024, 7:20 a.m. UTC

Struct lock_profile contains a pointer to the spinlock it is associated
with. Prepare support of differing spinlock_t and rspinlock_t types by
adding a type indicator of the pointer. Use the highest bit of the
block_cnt member for this indicator in order to not grow the struct
while hurting only the slow path with slightly less performant code.
Note that this requires a cast when printing the value in order to be
format compliant.

Signed-off-by: Juergen Gross <[e-mail]>
Acked-by: Alejandro Vallejo <[e-mail]>
Acked-by: Julien Grall <[e-mail]>
---
V2:
- new patch
V5:
- use bool for is_rlock (Julien Grall)
- use unsigned int for lockval in spinlock_profile_print_elem()
  (Jan Beulich)
- don't use anonymous union (Jan Beulich)
---
 xen/common/spinlock.c      | 28 ++++++++++++++++++++--------
 xen/include/xen/spinlock.h | 14 ++++++++++----
 2 files changed, 30 insertions(+), 12 deletions(-)

Patch

diff --git a/xen/common/spinlock.c b/xen/common/spinlock.c
index 5ef0ac7f89..0e8b525cec 100644
--- a/xen/common/spinlock.c
+++ b/xen/common/spinlock.c
@@ -538,19 +538,31 @@  static void spinlock_profile_iterate(lock_profile_subfunc *sub, void *par)
 static void cf_check spinlock_profile_print_elem(struct lock_profile *data,
     int32_t type, int32_t idx, void *par)
 {
-    struct spinlock *lock = data->lock;
+    unsigned int cpu;
+    unsigned int lockval;
+
+    if ( data->is_rlock )
+    {
+        cpu = data->ptr.rlock->debug.cpu;
+        lockval = data->ptr.rlock->tickets.head_tail;
+    }
+    else
+    {
+        cpu = data->ptr.lock->debug.cpu;
+        lockval = data->ptr.lock->tickets.head_tail;
+    }
 
     printk("%s ", lock_profile_ancs[type].name);
     if ( type != LOCKPROF_TYPE_GLOBAL )
         printk("%d ", idx);
-    printk("%s: addr=%p, lockval=%08x, ", data->name, lock,
-           lock->tickets.head_tail);
-    if ( lock->debug.cpu == SPINLOCK_NO_CPU )
+    printk("%s: addr=%p, lockval=%08x, ", data->name, data->ptr.lock, lockval);
+    if ( cpu == SPINLOCK_NO_CPU )
         printk("not locked\n");
     else
-        printk("cpu=%d\n", lock->debug.cpu);
-    printk("  lock:%" PRId64 "(%" PRI_stime "), block:%" PRId64 "(%" PRI_stime ")\n",
-           data->lock_cnt, data->time_hold, data->block_cnt, data->time_block);
+        printk("cpu=%u\n", cpu);
+    printk("  lock:%" PRIu64 "(%" PRI_stime "), block:%" PRIu64 "(%" PRI_stime ")\n",
+           data->lock_cnt, data->time_hold, (uint64_t)data->block_cnt,
+           data->time_block);
 }
 
 void cf_check spinlock_profile_printall(unsigned char key)
@@ -680,7 +692,7 @@  static int __init cf_check lock_prof_init(void)
     {
         (*q)->next = lock_profile_glb_q.elem_q;
         lock_profile_glb_q.elem_q = *q;
-        (*q)->lock->profile = *q;
+        (*q)->ptr.lock->profile = *q;
     }
 
     _lock_profile_register_struct(LOCKPROF_TYPE_GLOBAL,
diff --git a/xen/include/xen/spinlock.h b/xen/include/xen/spinlock.h
index afa24c8e29..49c5115f52 100644
--- a/xen/include/xen/spinlock.h
+++ b/xen/include/xen/spinlock.h
@@ -77,13 +77,19 @@  union lock_debug { };
 */
 
 struct spinlock;
+/* Temporary hack until a dedicated struct rspinlock is existing. */
+#define rspinlock spinlock
 
 struct lock_profile {
     struct lock_profile *next;       /* forward link */
     const char          *name;       /* lock name */
-    struct spinlock     *lock;       /* the lock itself */
+    union {
+        struct spinlock *lock;       /* the lock itself */
+        struct rspinlock *rlock;     /* the recursive lock itself */
+    } ptr;
     uint64_t            lock_cnt;    /* # of complete locking ops */
-    uint64_t            block_cnt;   /* # of complete wait for lock */
+    uint64_t            block_cnt:63; /* # of complete wait for lock */
+    bool                is_rlock:1;  /* use rlock pointer */
     s_time_t            time_hold;   /* cumulated lock time */
     s_time_t            time_block;  /* cumulated wait time */
     s_time_t            time_locked; /* system time of last locking */
@@ -95,7 +101,7 @@  struct lock_profile_qhead {
     int32_t                   idx;     /* index for printout */
 };
 
-#define LOCK_PROFILE_(lockname) { .name = #lockname, .lock = &(lockname), }
+#define LOCK_PROFILE_(lockname) { .name = #lockname, .ptr.lock = &(lockname), }
 #define LOCK_PROFILE_PTR_(name)                                               \
     static struct lock_profile * const lock_profile__##name                   \
     __used_section(".lockprofile.data") =                                     \
@@ -128,7 +134,7 @@  struct lock_profile_qhead {
             break;                                                            \
         }                                                                     \
         prof->name = #l;                                                      \
-        prof->lock = &(s)->l;                                                 \
+        prof->ptr.lock = &(s)->l;                                             \
         prof->next = (s)->profile_head.elem_q;                                \
         (s)->profile_head.elem_q = prof;                                      \
     } while( 0 )