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Netindex cleanup calls synchronize_rcu() by batches

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This commit is contained in:
Maria Matejka 2024-06-12 14:47:20 +02:00
parent 95d8329043
commit bd05dd7304
2 changed files with 54 additions and 35 deletions
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87
lib/netindex.c
View File

@ -10,7 +10,6 @@
#include "lib/netindex_private.h"
#define NETINDEX_INIT_BLOCK_SIZE 128
struct netindex netindex_in_progress;
#define NETINDEX_KEY(n) (n)->hash, (n)->addr
#define NETINDEX_NEXT(n) (n)->next
@ -90,6 +89,39 @@ netindex_hash_new(pool *sp, event_list *cleanup_target, u8 type)
return SKIP_BACK(netindex_hash, priv, nh);
}
static uint
netindex_hash_cleanup_removed(struct netindex_hash_private *nh, struct netindex * _Atomic *block, struct netindex **removed, uint cnt)
{
synchronize_rcu();
uint kept = 0;
for (uint q = 0; q < cnt; q++)
{
struct netindex *ni = removed[q];
/* Now no reader can possibly still have the old pointer,
* unless somebody found it inbetween and ref'd it. */
if (!lfuc_finished(&ni->uc))
{
/* Collision, return the netindex back. */
ASSERT_DIE(NULL == atomic_exchange_explicit(&block[ni->index], ni, memory_order_acq_rel));
SPINHASH_INSERT(nh->hash, NETINDEX, ni);
kept++;
continue;
}
/* Now the netindex is definitely obsolete, we can free it */
hmap_clear(&nh->id_map, ni->index);
if (nh->slab)
sl_free(ni);
else
mb_free(ni);
}
return kept;
}
static void
netindex_hash_cleanup(void *_nh)
{
@ -103,6 +135,10 @@ netindex_hash_cleanup(void *_nh)
uint bs = atomic_load_explicit(&nh->block_size, memory_order_relaxed);
struct netindex * _Atomic *block = atomic_load_explicit(&nh->block, memory_order_relaxed);
#define REMOVED_MAX 256
struct netindex *removed[REMOVED_MAX];
uint removed_cnt = 0;
for (uint i = 0; i < bs; i++)
{
struct netindex *ni = atomic_load_explicit(&block[i], memory_order_acquire);
@ -120,34 +156,26 @@ netindex_hash_cleanup(void *_nh)
continue;
}
/* Looks finished, try removing temporarily */
ASSERT_DIE(ni == atomic_exchange_explicit(&block[i], &netindex_in_progress, memory_order_acq_rel));
synchronize_rcu();
/* Now no reader can possibly still have the old pointer,
* unless somebody found it inbetween and ref'd it. */
if (!lfuc_finished(&ni->uc))
{
/* Collision, return the netindex to the block. */
ASSERT_DIE(&netindex_in_progress == atomic_exchange_explicit(&block[i], ni, memory_order_acq_rel));
kept++;
continue;
}
/* Now the netindex is definitely obsolete, set block to NULL */
ASSERT_DIE(&netindex_in_progress == atomic_exchange_explicit(&block[i], NULL, memory_order_acq_rel));
/* And free it from other structures */
/* Looks finished, try dropping */
ASSERT_DIE(ni == atomic_exchange_explicit(&block[i], NULL, memory_order_acq_rel));
SPINHASH_REMOVE(nh->hash, NETINDEX, ni);
hmap_clear(&nh->id_map, ni->index);
if (nh->slab)
sl_free(ni);
else
mb_free(ni);
/* Store into the removed-block */
removed[removed_cnt++] = ni;
/* If removed-block is full, flush it */
if (removed_cnt == REMOVED_MAX)
{
kept += netindex_hash_cleanup_removed(nh, block, removed, removed_cnt);
removed_cnt = 0;
}
}
/* Flush remaining netindexes */
if (removed_cnt)
kept += netindex_hash_cleanup_removed(nh, block, removed, removed_cnt);
/* Return now unless we're deleted */
if (kept || !nh->deleted_event)
{
UNLOCK_DOMAIN(attrs, dom);
@ -209,11 +237,7 @@ net_validate_index(netindex_hash *h, struct netindex *ni)
ASSERT_DIE(ni->index < bs);
struct netindex *bni = atomic_load_explicit(&block[ni->index], memory_order_acquire);
if (bni == ni)
return 1;
ASSERT_DIE(bni == &netindex_in_progress);
return 0;
return (bni == ni);
}
static struct netindex *
@ -320,8 +344,5 @@ net_resolve_index(netindex_hash *h, u32 i)
if (ni == NULL)
return NULL;
if (ni == &netindex_in_progress)
RCU_RETRY(u);
return net_lock_revive_unlock(h, ni);
}

2
lib/netindex_private.h
View File

@ -38,8 +38,6 @@ typedef union netindex_hash {
struct netindex_hash_private priv;
} netindex_hash;
extern struct netindex netindex_in_progress;
LOBJ_UNLOCK_CLEANUP(netindex_hash, attrs);
#define NH_LOCK(h, hp) LOBJ_LOCK(h, hp, netindex_hash, attrs)