diff mbox

[RFC,2/6] rhashtable: Call library function alloc_bucket_locks

Message ID 1473463197-3076903-3-git-send-email-tom@herbertland.com
State RFC, archived
Delegated to: David Miller
Headers show

Commit Message

Tom Herbert Sept. 9, 2016, 11:19 p.m. UTC 
To allocate the array of bucket locks for the hash table we now
call library function alloc_bucket_spinlocks. This function is
based on the old alloc_bucket_locks in rhashtable and should
produce the same effect.

Signed-off-by: Tom Herbert <tom@herbertland.com>
---
 lib/rhashtable.c | 46 ++++------------------------------------------
 1 file changed, 4 insertions(+), 42 deletions(-)

Comments

Thomas Graf Sept. 14, 2016, 9:18 a.m. UTC | #1 
On 09/09/16 at 04:19pm, Tom Herbert wrote:
> To allocate the array of bucket locks for the hash table we now
> call library function alloc_bucket_spinlocks. This function is
> based on the old alloc_bucket_locks in rhashtable and should
> produce the same effect.
> 
> Signed-off-by: Tom Herbert <tom@herbertland.com>

Acked-by: Thomas Graf <tgraf@suug.ch>
Herbert Xu Sept. 20, 2016, 1:49 a.m. UTC | #2 
Tom Herbert <tom@herbertland.com> wrote:
> To allocate the array of bucket locks for the hash table we now
> call library function alloc_bucket_spinlocks. This function is
> based on the old alloc_bucket_locks in rhashtable and should
> produce the same effect.
> 
> Signed-off-by: Tom Herbert <tom@herbertland.com>

This conflicts with the work I'm doing to fix the resize ENOMEM
issue.  I'll be making the hashtable as well as the spinlock table
nested, in which case you must not directly dereference it as an
array.

If you're just trying to share the spinlocks for another purpose,
what we can do is provide a helper function to return the right
lock for a given key/object.

Cheers,
diff mbox

Patch

diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index 06c2872..5b53304 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -59,50 +59,10 @@  EXPORT_SYMBOL_GPL(lockdep_rht_bucket_is_held);
 #define ASSERT_RHT_MUTEX(HT)
 #endif
 
-
-static int alloc_bucket_locks(struct rhashtable *ht, struct bucket_table *tbl,
-			      gfp_t gfp)
-{
-	unsigned int i, size;
-#if defined(CONFIG_PROVE_LOCKING)
-	unsigned int nr_pcpus = 2;
-#else
-	unsigned int nr_pcpus = num_possible_cpus();
-#endif
-
-	nr_pcpus = min_t(unsigned int, nr_pcpus, 64UL);
-	size = roundup_pow_of_two(nr_pcpus * ht->p.locks_mul);
-
-	/* Never allocate more than 0.5 locks per bucket */
-	size = min_t(unsigned int, size, tbl->size >> 1);
-
-	if (sizeof(spinlock_t) != 0) {
-		tbl->locks = NULL;
-#ifdef CONFIG_NUMA
-		if (size * sizeof(spinlock_t) > PAGE_SIZE &&
-		    gfp == GFP_KERNEL)
-			tbl->locks = vmalloc(size * sizeof(spinlock_t));
-#endif
-		if (gfp != GFP_KERNEL)
-			gfp |= __GFP_NOWARN | __GFP_NORETRY;
-
-		if (!tbl->locks)
-			tbl->locks = kmalloc_array(size, sizeof(spinlock_t),
-						   gfp);
-		if (!tbl->locks)
-			return -ENOMEM;
-		for (i = 0; i < size; i++)
-			spin_lock_init(&tbl->locks[i]);
-	}
-	tbl->locks_mask = size - 1;
-
-	return 0;
-}
-
 static void bucket_table_free(const struct bucket_table *tbl)
 {
 	if (tbl)
-		kvfree(tbl->locks);
+		free_bucket_spinlocks(tbl->locks);
 
 	kvfree(tbl);
 }
@@ -131,7 +91,9 @@  static struct bucket_table *bucket_table_alloc(struct rhashtable *ht,
 
 	tbl->size = nbuckets;
 
-	if (alloc_bucket_locks(ht, tbl, gfp) < 0) {
+	/* Never allocate more than 0.5 locks per bucket */
+	if (alloc_bucket_spinlocks(&tbl->locks, &tbl->locks_mask,
+				   tbl->size >> 1, ht->p.locks_mul, gfp)) {
 		bucket_table_free(tbl);
 		return NULL;
 	}