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authorThomas Graf <tgraf@suug.ch>2014-11-13 13:45:46 +0100
committerDavid S. Miller <davem@davemloft.net>2014-11-13 15:18:40 -0500
commit6eba82248ef47fd478f940a418429e3ec95cb3db (patch)
tree77e82bd157c6b164347f02ba6c33e5abe4860f86 /lib
parent64bb7e9949c03bff9463c40bfa740f611fb5500d (diff)
rhashtable: Drop gfp_flags arg in insert/remove functions
Reallocation is only required for shrinking and expanding and both rely on a mutex for synchronization and callers of rhashtable_init() are in non atomic context. Therefore, no reason to continue passing allocation hints through the API. Instead, use GFP_KERNEL and add __GFP_NOWARN | __GFP_NORETRY to allow for silent fall back to vzalloc() without the OOM killer jumping in as pointed out by Eric Dumazet and Eric W. Biederman. Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'lib')
-rw-r--r--lib/rhashtable.c41
1 files changed, 17 insertions, 24 deletions
diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index 4b4b53bfa08b..25e4c213b08a 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -107,13 +107,13 @@ static u32 head_hashfn(const struct rhashtable *ht,
return obj_hashfn(ht, rht_obj(ht, he), hsize);
}
-static struct bucket_table *bucket_table_alloc(size_t nbuckets, gfp_t flags)
+static struct bucket_table *bucket_table_alloc(size_t nbuckets)
{
struct bucket_table *tbl;
size_t size;
size = sizeof(*tbl) + nbuckets * sizeof(tbl->buckets[0]);
- tbl = kzalloc(size, flags);
+ tbl = kzalloc(size, GFP_KERNEL | __GFP_NOWARN);
if (tbl == NULL)
tbl = vzalloc(size);
@@ -200,7 +200,6 @@ static void hashtable_chain_unzip(const struct rhashtable *ht,
/**
* rhashtable_expand - Expand hash table while allowing concurrent lookups
* @ht: the hash table to expand
- * @flags: allocation flags
*
* A secondary bucket array is allocated and the hash entries are migrated
* while keeping them on both lists until the end of the RCU grace period.
@@ -211,7 +210,7 @@ static void hashtable_chain_unzip(const struct rhashtable *ht,
* The caller must ensure that no concurrent table mutations take place.
* It is however valid to have concurrent lookups if they are RCU protected.
*/
-int rhashtable_expand(struct rhashtable *ht, gfp_t flags)
+int rhashtable_expand(struct rhashtable *ht)
{
struct bucket_table *new_tbl, *old_tbl = rht_dereference(ht->tbl, ht);
struct rhash_head *he;
@@ -223,7 +222,7 @@ int rhashtable_expand(struct rhashtable *ht, gfp_t flags)
if (ht->p.max_shift && ht->shift >= ht->p.max_shift)
return 0;
- new_tbl = bucket_table_alloc(old_tbl->size * 2, flags);
+ new_tbl = bucket_table_alloc(old_tbl->size * 2);
if (new_tbl == NULL)
return -ENOMEM;
@@ -281,7 +280,6 @@ EXPORT_SYMBOL_GPL(rhashtable_expand);
/**
* rhashtable_shrink - Shrink hash table while allowing concurrent lookups
* @ht: the hash table to shrink
- * @flags: allocation flags
*
* This function may only be called in a context where it is safe to call
* synchronize_rcu(), e.g. not within a rcu_read_lock() section.
@@ -289,7 +287,7 @@ EXPORT_SYMBOL_GPL(rhashtable_expand);
* The caller must ensure that no concurrent table mutations take place.
* It is however valid to have concurrent lookups if they are RCU protected.
*/
-int rhashtable_shrink(struct rhashtable *ht, gfp_t flags)
+int rhashtable_shrink(struct rhashtable *ht)
{
struct bucket_table *ntbl, *tbl = rht_dereference(ht->tbl, ht);
struct rhash_head __rcu **pprev;
@@ -300,7 +298,7 @@ int rhashtable_shrink(struct rhashtable *ht, gfp_t flags)
if (ht->shift <= ht->p.min_shift)
return 0;
- ntbl = bucket_table_alloc(tbl->size / 2, flags);
+ ntbl = bucket_table_alloc(tbl->size / 2);
if (ntbl == NULL)
return -ENOMEM;
@@ -341,7 +339,6 @@ EXPORT_SYMBOL_GPL(rhashtable_shrink);
* rhashtable_insert - insert object into hash hash table
* @ht: hash table
* @obj: pointer to hash head inside object
- * @flags: allocation flags (table expansion)
*
* Will automatically grow the table via rhashtable_expand() if the the
* grow_decision function specified at rhashtable_init() returns true.
@@ -349,8 +346,7 @@ EXPORT_SYMBOL_GPL(rhashtable_shrink);
* The caller must ensure that no concurrent table mutations occur. It is
* however valid to have concurrent lookups if they are RCU protected.
*/
-void rhashtable_insert(struct rhashtable *ht, struct rhash_head *obj,
- gfp_t flags)
+void rhashtable_insert(struct rhashtable *ht, struct rhash_head *obj)
{
struct bucket_table *tbl = rht_dereference(ht->tbl, ht);
u32 hash;
@@ -363,7 +359,7 @@ void rhashtable_insert(struct rhashtable *ht, struct rhash_head *obj,
ht->nelems++;
if (ht->p.grow_decision && ht->p.grow_decision(ht, tbl->size))
- rhashtable_expand(ht, flags);
+ rhashtable_expand(ht);
}
EXPORT_SYMBOL_GPL(rhashtable_insert);
@@ -372,14 +368,13 @@ EXPORT_SYMBOL_GPL(rhashtable_insert);
* @ht: hash table
* @obj: pointer to hash head inside object
* @pprev: pointer to previous element
- * @flags: allocation flags (table expansion)
*
* Identical to rhashtable_remove() but caller is alreayd aware of the element
* in front of the element to be deleted. This is in particular useful for
* deletion when combined with walking or lookup.
*/
void rhashtable_remove_pprev(struct rhashtable *ht, struct rhash_head *obj,
- struct rhash_head __rcu **pprev, gfp_t flags)
+ struct rhash_head __rcu **pprev)
{
struct bucket_table *tbl = rht_dereference(ht->tbl, ht);
@@ -390,7 +385,7 @@ void rhashtable_remove_pprev(struct rhashtable *ht, struct rhash_head *obj,
if (ht->p.shrink_decision &&
ht->p.shrink_decision(ht, tbl->size))
- rhashtable_shrink(ht, flags);
+ rhashtable_shrink(ht);
}
EXPORT_SYMBOL_GPL(rhashtable_remove_pprev);
@@ -398,7 +393,6 @@ EXPORT_SYMBOL_GPL(rhashtable_remove_pprev);
* rhashtable_remove - remove object from hash table
* @ht: hash table
* @obj: pointer to hash head inside object
- * @flags: allocation flags (table expansion)
*
* Since the hash chain is single linked, the removal operation needs to
* walk the bucket chain upon removal. The removal operation is thus
@@ -410,8 +404,7 @@ EXPORT_SYMBOL_GPL(rhashtable_remove_pprev);
* The caller must ensure that no concurrent table mutations occur. It is
* however valid to have concurrent lookups if they are RCU protected.
*/
-bool rhashtable_remove(struct rhashtable *ht, struct rhash_head *obj,
- gfp_t flags)
+bool rhashtable_remove(struct rhashtable *ht, struct rhash_head *obj)
{
struct bucket_table *tbl = rht_dereference(ht->tbl, ht);
struct rhash_head __rcu **pprev;
@@ -429,7 +422,7 @@ bool rhashtable_remove(struct rhashtable *ht, struct rhash_head *obj,
continue;
}
- rhashtable_remove_pprev(ht, he, pprev, flags);
+ rhashtable_remove_pprev(ht, he, pprev);
return true;
}
@@ -576,7 +569,7 @@ int rhashtable_init(struct rhashtable *ht, struct rhashtable_params *params)
if (params->nelem_hint)
size = rounded_hashtable_size(params);
- tbl = bucket_table_alloc(size, GFP_KERNEL);
+ tbl = bucket_table_alloc(size);
if (tbl == NULL)
return -ENOMEM;
@@ -713,7 +706,7 @@ static int __init test_rhashtable(struct rhashtable *ht)
obj->ptr = TEST_PTR;
obj->value = i * 2;
- rhashtable_insert(ht, &obj->node, GFP_KERNEL);
+ rhashtable_insert(ht, &obj->node);
}
rcu_read_lock();
@@ -724,7 +717,7 @@ static int __init test_rhashtable(struct rhashtable *ht)
for (i = 0; i < TEST_NEXPANDS; i++) {
pr_info(" Table expansion iteration %u...\n", i);
- rhashtable_expand(ht, GFP_KERNEL);
+ rhashtable_expand(ht);
rcu_read_lock();
pr_info(" Verifying lookups...\n");
@@ -734,7 +727,7 @@ static int __init test_rhashtable(struct rhashtable *ht)
for (i = 0; i < TEST_NEXPANDS; i++) {
pr_info(" Table shrinkage iteration %u...\n", i);
- rhashtable_shrink(ht, GFP_KERNEL);
+ rhashtable_shrink(ht);
rcu_read_lock();
pr_info(" Verifying lookups...\n");
@@ -749,7 +742,7 @@ static int __init test_rhashtable(struct rhashtable *ht)
obj = rhashtable_lookup(ht, &key);
BUG_ON(!obj);
- rhashtable_remove(ht, &obj->node, GFP_KERNEL);
+ rhashtable_remove(ht, &obj->node);
kfree(obj);
}

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