| Message ID | E1YY9qm-0005mA-Jy@gondolin.me.apana.org.au |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
On 03/18/15 at 08:01pm, Herbert Xu wrote: > @@ -935,6 +938,7 @@ int rhashtable_init(struct rhashtable *ht, struct rhashtable_params *params) > > params->min_shift = max_t(size_t, params->min_shift, > ilog2(HASH_MIN_SIZE)); > + params->min_size = max(params->min_size, HASH_MIN_SIZE); > > if (params->nelem_hint) > size = rounded_hashtable_size(params); The only change I would add on top is to ensure that min_size and max_size are a power of two as otherwise the table size used will end up being greater or smaller than specified. I can do that as a follow-up though. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Thomas Graf <tgraf@suug.ch> Date: Wed, 18 Mar 2015 10:55:28 +0000 > On 03/18/15 at 08:01pm, Herbert Xu wrote: >> @@ -935,6 +938,7 @@ int rhashtable_init(struct rhashtable *ht, struct rhashtable_params *params) >> >> params->min_shift = max_t(size_t, params->min_shift, >> ilog2(HASH_MIN_SIZE)); >> + params->min_size = max(params->min_size, HASH_MIN_SIZE); >> >> if (params->nelem_hint) >> size = rounded_hashtable_size(params); > > The only change I would add on top is to ensure that min_size > and max_size are a power of two as otherwise the table size > used will end up being greater or smaller than specified. > I can do that as a follow-up though. Feel free. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Thomas Graf > On 03/18/15 at 08:01pm, Herbert Xu wrote: > > @@ -935,6 +938,7 @@ int rhashtable_init(struct rhashtable *ht, struct rhashtable_params *params) > > > > params->min_shift = max_t(size_t, params->min_shift, > > ilog2(HASH_MIN_SIZE)); > > + params->min_size = max(params->min_size, HASH_MIN_SIZE); > > > > if (params->nelem_hint) > > size = rounded_hashtable_size(params); > > The only change I would add on top is to ensure that min_size > and max_size are a power of two as otherwise the table size > used will end up being greater or smaller than specified. I'd just make sure that 'something sensible' happens if they aren't. You don't really want to error the table creation if some sysctl (etc) that control the sizes isn't a power of 2. David -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h index f16e856..81267fe 100644 --- a/include/linux/rhashtable.h +++ b/include/linux/rhashtable.h @@ -85,6 +85,8 @@ struct rhashtable; * @head_offset: Offset of rhash_head in struct to be hashed * @max_shift: Maximum number of shifts while expanding * @min_shift: Minimum number of shifts while shrinking + * @max_size: Maximum size while expanding + * @min_size: Minimum size while shrinking * @nulls_base: Base value to generate nulls marker * @locks_mul: Number of bucket locks to allocate per cpu (default: 128) * @hashfn: Function to hash key @@ -97,6 +99,8 @@ struct rhashtable_params { size_t head_offset; size_t max_shift; size_t min_shift; + unsigned int max_size; + unsigned int min_size; u32 nulls_base; size_t locks_mul; rht_hashfn_t hashfn; diff --git a/lib/rhashtable.c b/lib/rhashtable.c index 0974003..c4061bb 100644 --- a/lib/rhashtable.c +++ b/lib/rhashtable.c @@ -27,7 +27,7 @@ #include <linux/err.h> #define HASH_DEFAULT_SIZE 64UL -#define HASH_MIN_SIZE 4UL +#define HASH_MIN_SIZE 4U #define BUCKET_LOCKS_PER_CPU 128UL /* Base bits plus 1 bit for nulls marker */ @@ -188,7 +188,8 @@ static bool rht_grow_above_75(const struct rhashtable *ht, { /* Expand table when exceeding 75% load */ return atomic_read(&ht->nelems) > (tbl->size / 4 * 3) && - (!ht->p.max_shift || tbl->size < (1 << ht->p.max_shift)); + (!ht->p.max_shift || tbl->size < (1 << ht->p.max_shift)) && + (!ht->p.max_size || tbl->size < ht->p.max_size); } /** @@ -201,7 +202,8 @@ static bool rht_shrink_below_30(const struct rhashtable *ht, { /* Shrink table beneath 30% load */ return atomic_read(&ht->nelems) < (tbl->size * 3 / 10) && - tbl->size > (1 << ht->p.min_shift); + tbl->size > (1 << ht->p.min_shift) && + tbl->size > ht->p.min_size; } static int rhashtable_rehash_one(struct rhashtable *ht, unsigned old_hash) @@ -873,7 +875,8 @@ EXPORT_SYMBOL_GPL(rhashtable_walk_stop); static size_t rounded_hashtable_size(struct rhashtable_params *params) { return max(roundup_pow_of_two(params->nelem_hint * 4 / 3), - 1UL << params->min_shift); + max(1UL << params->min_shift, + (unsigned long)params->min_size)); } /** @@ -935,6 +938,7 @@ int rhashtable_init(struct rhashtable *ht, struct rhashtable_params *params) params->min_shift = max_t(size_t, params->min_shift, ilog2(HASH_MIN_SIZE)); + params->min_size = max(params->min_size, HASH_MIN_SIZE); if (params->nelem_hint) size = rounded_hashtable_size(params);
This patch adds the parameters max_size and min_size which are meant to replace max_shift and min_shift. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> --- include/linux/rhashtable.h | 4 ++++ lib/rhashtable.c | 12 ++++++++---- 2 files changed, 12 insertions(+), 4 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html