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authorDave Barach <dave@barachs.net>2018-02-07 13:14:06 -0500
committerDamjan Marion <dmarion.lists@gmail.com>2018-02-08 10:02:16 +0000
commite7d212fe41de88863884dc24dff9e24e5f37b421 (patch)
tree4d38c30d330de2ce27207bdcee537f7874f62574 /src/vppinfra/bihash_template.c
parentdb3c480e375bd7eb22c27887590c8dca07293719 (diff)
Minimize bihash memory consumption
Reference-count the number of entries in each bucket. If the reference count goes to zero, free the backing store. Add long-term churn-testing to test_bihash_template.c, thanks to Andrew Yourtchenko for the initial implementation. Change-Id: I4fbd9229cacfaba8027a85cbf87b74afdead6e39 Signed-off-by: Dave Barach <dave@barachs.net>
Diffstat (limited to 'src/vppinfra/bihash_template.c')
-rw-r--r--src/vppinfra/bihash_template.c55
1 files changed, 46 insertions, 9 deletions
diff --git a/src/vppinfra/bihash_template.c b/src/vppinfra/bihash_template.c
index 3f25b02d5df..2b40af31d6f 100644
--- a/src/vppinfra/bihash_template.c
+++ b/src/vppinfra/bihash_template.c
@@ -290,6 +290,7 @@ int BV (clib_bihash_add_del)
*v->kvp = *add_v;
tmp_b.as_u64 = 0;
tmp_b.offset = BV (clib_bihash_get_offset) (h, v);
+ tmp_b.refcnt = 1;
b->as_u64 = tmp_b.as_u64;
goto unlock;
@@ -329,6 +330,7 @@ int BV (clib_bihash_add_del)
clib_memcpy (&(v->kvp[i]), add_v, sizeof (*add_v));
CLIB_MEMORY_BARRIER ();
b->as_u64 = h->saved_bucket.as_u64;
+ b->refcnt++;
goto unlock;
}
}
@@ -342,8 +344,17 @@ int BV (clib_bihash_add_del)
{
memset (&(v->kvp[i]), 0xff, sizeof (*(add_v)));
CLIB_MEMORY_BARRIER ();
- b->as_u64 = h->saved_bucket.as_u64;
- goto unlock;
+ if (PREDICT_TRUE (h->saved_bucket.refcnt > 1))
+ {
+ h->saved_bucket.refcnt -= 1;
+ b->as_u64 = h->saved_bucket.as_u64;
+ goto unlock;
+ }
+ else
+ {
+ tmp_b.as_u64 = 0;
+ goto free_old_bucket;
+ }
}
}
rv = -3;
@@ -411,18 +422,18 @@ int BV (clib_bihash_add_del)
goto try_resplit;
expand_ok:
- /* Keep track of the number of linear-scan buckets */
- if (tmp_b.linear_search ^ mark_bucket_linear)
- h->linear_buckets += (mark_bucket_linear == 1) ? 1 : -1;
-
tmp_b.log2_pages = new_log2_pages;
tmp_b.offset = BV (clib_bihash_get_offset) (h, save_new_v);
tmp_b.linear_search = mark_bucket_linear;
+ tmp_b.refcnt = h->saved_bucket.refcnt + 1;
+
+free_old_bucket:
CLIB_MEMORY_BARRIER ();
b->as_u64 = tmp_b.as_u64;
v = BV (clib_bihash_get_value) (h, h->saved_bucket.offset);
- BV (value_free) (h, v, old_log2_pages);
+
+ BV (value_free) (h, v, h->saved_bucket.log2_pages);
unlock:
BV (clib_bihash_reset_cache) (b);
@@ -541,6 +552,8 @@ u8 *BV (format_bihash) (u8 * s, va_list * args)
BVT (clib_bihash_value) * v;
int i, j, k;
u64 active_elements = 0;
+ u64 active_buckets = 0;
+ u64 linear_buckets = 0;
s = format (s, "Hash table %s\n", h->name ? h->name : (u8 *) "(unnamed)");
@@ -554,6 +567,11 @@ u8 *BV (format_bihash) (u8 * s, va_list * args)
continue;
}
+ active_buckets++;
+
+ if (b->linear_search)
+ linear_buckets++;
+
if (verbose)
{
s = format (s, "[%d]: heap offset %d, len %d, linear %d\n", i,
@@ -593,11 +611,30 @@ u8 *BV (format_bihash) (u8 * s, va_list * args)
}
}
- s = format (s, " %lld active elements\n", active_elements);
+ s = format (s, " %lld active elements %lld active buckets\n",
+ active_elements, active_buckets);
s = format (s, " %d free lists\n", vec_len (h->freelists));
- s = format (s, " %d linear search buckets\n", h->linear_buckets);
+
+ for (i = 0; i < vec_len (h->freelists); i++)
+ {
+ u32 nfree = 0;
+ BVT (clib_bihash_value) * free_elt;
+
+ free_elt = h->freelists[i];
+ while (free_elt)
+ {
+ nfree++;
+ free_elt = free_elt->next_free;
+ }
+
+ s = format (s, " [len %d] %u free elts\n", 1 << i, nfree);
+ }
+
+ s = format (s, " %lld linear search buckets\n", linear_buckets);
s = format (s, " %lld cache hits, %lld cache misses\n",
h->cache_hits, h->cache_misses);
+ if (h->mheap)
+ s = format (s, " mheap: %U", format_mheap, h->mheap, 0 /* verbose */ );
return s;
}