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Re: [PATCH v4 06/12] xen/spinlock: make struct lock_profile rspinlock_t aware



Hi,

On 12/12/2023 09:47, Juergen Gross wrote:
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.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Acked-by: Alejandro Vallejo <alejandro.vallejo@xxxxxxxxx>
---
V2:
- new patch
---
  xen/common/spinlock.c      | 26 +++++++++++++++++++-------
  xen/include/xen/spinlock.h | 10 ++++++++--
  2 files changed, 27 insertions(+), 9 deletions(-)

diff --git a/xen/common/spinlock.c b/xen/common/spinlock.c
index c1a9ba1304..7d611d3d7d 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;
+    uint32_t lockval;
+
+    if ( data->is_rlock )
+    {
+        cpu = data->rlock->debug.cpu;
+        lockval = data->rlock->tickets.head_tail;
+    }
+    else
+    {
+        cpu = data->lock->debug.cpu;
+        lockval = data->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->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)
diff --git a/xen/include/xen/spinlock.h b/xen/include/xen/spinlock.h
index 05b97c1e03..ac3bef267a 100644
--- a/xen/include/xen/spinlock.h
+++ b/xen/include/xen/spinlock.h
@@ -76,13 +76,19 @@ 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 */
+    };
      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 */
+    uint64_t            is_rlock:1;  /* use rlock pointer */

This is meant to act like a bool. So I would prefer if we use:

bool is_rwlock:1;

And then use true/false when set.

Acked-by: Julien Grall <jgrall@xxxxxxxxxx>

      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 */

Cheers,

--
Julien Grall



 


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