"size < target_size" in cds_lfht_resize_lazy() which is always true confuses me.
I think we should grow the ht only when we success to increase the resize_target. Signed-off-by: Lai Jiangshan <[email protected]> --- rculfhash.c | 25 +++++++++++++------------ 1 files changed, 13 insertions(+), 12 deletions(-) diff --git a/rculfhash.c b/rculfhash.c index da37e97..e97d854 100644 --- a/rculfhash.c +++ b/rculfhash.c @@ -498,7 +498,7 @@ int get_count_order_ulong(unsigned long x) #endif static -void cds_lfht_resize_lazy(struct cds_lfht *ht, unsigned long size, int growth); +void cds_lfht_resize_lazy_grow(struct cds_lfht *ht, unsigned long size, int growth); static void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size, @@ -659,7 +659,7 @@ void check_resize(struct cds_lfht *ht, unsigned long size, uint32_t chain_len) dbg_printf("WARNING: large chain length: %u.\n", chain_len); if (chain_len >= CHAIN_LEN_RESIZE_THRESHOLD) - cds_lfht_resize_lazy(ht, size, + cds_lfht_resize_lazy_grow(ht, size, get_count_order_u32(chain_len - (CHAIN_LEN_TARGET - 1))); } @@ -706,7 +706,8 @@ int is_end(struct cds_lfht_node *node) } static -unsigned long _uatomic_max(unsigned long *ptr, unsigned long v) +unsigned long _uatomic_xchg_monotonic_increase(unsigned long *ptr, + unsigned long v) { unsigned long old1, old2; @@ -716,7 +717,7 @@ unsigned long _uatomic_max(unsigned long *ptr, unsigned long v) if (old2 >= v) return old2; } while ((old1 = uatomic_cmpxchg(ptr, old2, v)) != old2); - return v; + return old2; } static @@ -1716,11 +1717,9 @@ void _do_cds_lfht_resize(struct cds_lfht *ht) } static -unsigned long resize_target_update(struct cds_lfht *ht, unsigned long size, - int growth_order) +unsigned long resize_target_grow(struct cds_lfht *ht, unsigned long new_size) { - return _uatomic_max(&ht->t.resize_target, - size << growth_order); + return _uatomic_xchg_monotonic_increase(&ht->t.resize_target, new_size); } static @@ -1760,15 +1759,17 @@ void do_resize_cb(struct rcu_head *head) } static -void cds_lfht_resize_lazy(struct cds_lfht *ht, unsigned long size, int growth) +void cds_lfht_resize_lazy_grow(struct cds_lfht *ht, unsigned long size, int growth) { struct rcu_resize_work *work; - unsigned long target_size; + unsigned long target_size = size << growth; + + if (resize_target_grow(ht, target_size) >= target_size) + return; - target_size = resize_target_update(ht, size, growth); /* Store resize_target before read resize_initiated */ cmm_smp_mb(); - if (!CMM_LOAD_SHARED(ht->t.resize_initiated) && size < target_size) { + if (!CMM_LOAD_SHARED(ht->t.resize_initiated)) { uatomic_inc(&ht->in_progress_resize); cmm_smp_mb(); /* increment resize count before load destroy */ if (CMM_LOAD_SHARED(ht->in_progress_destroy)) { -- 1.7.4.4 _______________________________________________ ltt-dev mailing list [email protected] http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev
