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This commit is contained in:
Witold Kręcicki
2020-02-10 10:44:35 +01:00
parent 96ff385777
commit c9e6c59bc2
1 changed files with 81 additions and 31 deletions
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lib/dns/lowac.c
+81 -31
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@@ -17,7 +17,7 @@
#include <ck_ht.h>
#include <ck_fifo.h>
#include <ck_queue.h>
#define fprintf(...) {}
#define MAXIMUM_PKT_SIZE 1024
#define LENTRY_MAGIC ISC_MAGIC('L', 'o', 'w', 'E')
@@ -33,7 +33,6 @@ struct dns_lowac_entry {
unsigned char *blob;
uint32_t blobsize;
isc_refcount_t refcount;
/*
* Set to 'true' when we enqueue this entry on remq.
* Nothing serious will happen if we enqueue the entry
@@ -41,22 +40,33 @@ struct dns_lowac_entry {
* It's not locked in any way as it can only change
* from false to true during runtime.
*/
bool remq_enqueued;
bool remq_enqueued;
isc_refcount_t rqrefcount;
bool inht;
atomic_int_fast64_t lastusage;
};
struct dns_lowac {
bool running;
ck_ht_t ht;
isc_mem_t * mctx;
isc_interval_t expiry;
isc_thread_t thread;
int count;
ck_ht_iterator_t htit;
ck_fifo_mpmc_t inq;
ck_fifo_mpmc_t remq;
isc_mem_t * mctx;
isc_thread_t thread;
isc_interval_t expiry; /* Time after which records expire */
bool running; /* We're not shut down */
bool accepting; /* We're accepting packets into cache */
ck_ht_t ht; /* Cache hash table */
ck_ht_iterator_t htit; /* Hashtable maintenance iterator */
ck_fifo_mpmc_t inq; /* Packet input queue */
ck_fifo_mpmc_t remq; /* Removal queue */
atomic_int_fast64_t now; /* Epoch time, updated at every loop */
int count;
};
static void *
@@ -122,14 +132,16 @@ dequeue_input_entry(dns_lowac_t*lowac) {
entry->inht = true;
if (ck_ht_put_spmc(&lowac->ht, entry->hash,
&htentry) == false) {
abort();
printf("oddness but might happen\n");
/* We can do it safely as it never was in
* hashtable */
RUNTIME_CHECK(isc_refcount_decrement(&entry->
refcount) ==
0);
1);
free_entry(lowac, entry);
} else {
fprintf(stderr, "XXXInsert %p %d\n", entry, lowac->count);
lowac->count++;
}
} else {
@@ -144,7 +156,8 @@ dequeue_input_entry(dns_lowac_t*lowac) {
entry->inht = true;
RUNTIME_CHECK(ck_ht_set_spmc(&lowac->ht, entry->hash,
&htentry) == true);
lowac->count++;
/*
* We don't need to increment refcount since we
* have not decremented it
@@ -155,6 +168,8 @@ dequeue_input_entry(dns_lowac_t*lowac) {
(sizeof(
ck_fifo_mpmc_entry_t)));
oldentry->remq_enqueued = true;
isc_refcount_increment(&oldentry->rqrefcount);
fprintf(stderr, "XXXenq %p %d\n", oldentry, __LINE__);
ck_fifo_mpmc_enqueue(&lowac->remq, qentry,
oldentry);
}
@@ -175,16 +190,18 @@ expire_entries(dns_lowac_t *lowac) {
ck_ht_iterator_init(&lowac->htit);
iterok = ck_ht_next(&lowac->ht, &lowac->htit, &htitentry);
}
while (iterok && htitentry != NULL && iterated < 256) {
while (iterok && htitentry != NULL && iterated < 2048) {
dns_lowac_entry_t *entry = ck_ht_entry_value(htitentry);
REQUIRE(VALID_LENTRY(entry));
if (isc_time_compare(&entry->expire, &now) < 0) {
if (!ck_ht_remove_spmc(&lowac->ht, entry->hash, htitentry)) {
abort();
/*
* Very unlikely, but can happen when we're between generations.
* TODO verify that it's ok at all, maybe we're using the iterator wrong?
*/
isc_refcount_increment(&entry->refcount);
fprintf(stderr, "INCREF %d %p\n", __LINE__, entry);
} else {
dns_lowac_entry_t *ent2 = ck_ht_entry_value(htitentry);
RUNTIME_CHECK(ent2 == entry);
@@ -199,6 +216,8 @@ expire_entries(dns_lowac_t *lowac) {
(sizeof(
ck_fifo_mpmc_entry_t)));
entry->remq_enqueued = true;
isc_refcount_increment(&entry->rqrefcount);
fprintf(stderr, "XXXenq %p %d\n", entry, __LINE__);
ck_fifo_mpmc_enqueue(&lowac->remq, qentry, entry);
}
htitentry = NULL;
@@ -231,6 +250,8 @@ cleanup_entries(dns_lowac_t *lowac) {
{
REQUIRE(VALID_LENTRY(entry));
int rc = isc_refcount_decrement(&entry->refcount);
int rqrc = isc_refcount_decrement(&entry->rqrefcount);
fprintf(stderr, "DECREF %d %p %d\n", __LINE__, entry, lowac->count);
if (entry->inht) {
/*
* Remove entry from the hashtable, we'll remove the
@@ -242,19 +263,33 @@ cleanup_entries(dns_lowac_t *lowac) {
entry->hash,
&htentry) == true);
entry->inht = false;
isc_refcount_increment(&entry->refcount);
isc_refcount_increment(&entry->rqrefcount);
/* We don't increment refcount - it was at 2 (remq + ht), it stays at 1 (remq) */
fprintf(stderr, "INCREF %d %p\n", __LINE__, entry);
fprintf(stderr, "XXXenq %p %d\n", entry, __LINE__);
ck_fifo_mpmc_enqueue(&lowac->remq, qentry, entry);
} else {
if (rc > 1) {
/* Requeue if still in use */
isc_refcount_increment(&entry->refcount);
ck_fifo_mpmc_enqueue(&lowac->remq, qentry,
entry);
/* Requeue if still in use and there's no other request in queue */
/* TODO that's completely wrong, if we have two instances in the queue they will always have rc > 1 !!! */
if (rqrc == 0) {
int p1 = isc_refcount_increment(&entry->rqrefcount);
int p2 = isc_refcount_increment(&entry->refcount);
fprintf(stderr, "INCREF %d %p %d %d\n", __LINE__, entry, p1, p2);
fprintf(stderr, "XXXenq %p %d\n", entry, __LINE__);
ck_fifo_mpmc_enqueue(&lowac->remq, qentry,
entry);
} else {
isc_mem_put(lowac->mctx, qentry,
sizeof(*qentry));
}
fprintf(stderr, "IGNREF %d %p\n", __LINE__, entry);
} else {
isc_mem_put(lowac->mctx, qentry,
sizeof(*qentry));
removed++;
free_entry(lowac, entry);
fprintf(stderr, "XXXFree %p %d\n", entry, lowac->count);
lowac->count--;
}
}
@@ -272,7 +307,7 @@ rthread(void *d) {
expire_entries(lowac);
int removed = cleanup_entries(lowac);
if (removed < 256) {
usleep(10000);
usleep(1000);
} else {
RUNTIME_CHECK(ck_ht_gc(&lowac->ht, 128,
isc_random32()));
@@ -284,6 +319,17 @@ rthread(void *d) {
dns_lowac_t*
dns_lowac_create(isc_mem_t *mctx) {
dns_lowac_t *lowac = isc_mem_get(mctx, sizeof(dns_lowac_t));
isc_interval_set(&lowac->expiry, 600, 0);
lowac->count = 0;
lowac->running = true;
if (ck_ht_init(&lowac->ht,
CK_HT_MODE_BYTESTRING | CK_HT_WORKLOAD_DELETE,
ht_hash_wrapper,
&my_allocator, 32, isc_random32()) == false) {
abort();
}
ck_fifo_mpmc_entry_t *inq_stub =
isc_mem_get(mctx, sizeof(ck_fifo_mpmc_entry_t));
ck_fifo_mpmc_entry_t *remq_stub =
@@ -291,16 +337,11 @@ dns_lowac_create(isc_mem_t *mctx) {
ck_fifo_mpmc_init(&lowac->inq, inq_stub);
ck_fifo_mpmc_init(&lowac->remq, remq_stub);
lowac->count = 0;
lowac->running = true;
if (ck_ht_init(&lowac->ht,
CK_HT_MODE_BYTESTRING | CK_HT_WORKLOAD_DELETE,
ht_hash_wrapper,
&my_allocator, 32, isc_random32()) == false) {
abort();
}
lowac->mctx = NULL;
isc_mem_attach(mctx, &lowac->mctx);
isc_interval_set(&lowac->expiry, 120, 0);
isc_thread_create(rthread, lowac, &lowac->thread);
return (lowac);
}
@@ -329,8 +370,11 @@ dns_lowac_destroy(dns_lowac_t *lowac) {
&entry,
&fentry))
{
if (isc_refcount_decrement(&entry->refcount) == 0) {
if (isc_refcount_decrement(&entry->refcount) == 1) {
fprintf(stderr, "DECREF %d %p\n", __LINE__, entry);
free_entry(lowac, entry);
} else {
fprintf(stderr, "Non-unreferenced entry in remq %p\n", entry);
}
isc_mem_put(lowac->mctx, fentry, sizeof(*fentry));
}
@@ -373,6 +417,7 @@ dns_lowac_put(dns_lowac_t *lowac, dns_name_t *name, char*packet, int size) {
memcpy(entry->blob, packet, size);
entry->blobsize = size;
isc_refcount_init(&entry->refcount, 1);
isc_refcount_init(&entry->rqrefcount, 0);
isc_time_nowplusinterval(&entry->expire, &lowac->expiry);
entry->remq_enqueued = false;
entry->inht = false;
@@ -405,10 +450,12 @@ dns_lowac_get(dns_lowac_t *lowac, dns_name_t *name, unsigned char *blob,
dns_lowac_entry_t *entry = ck_ht_entry_value(&htentry);
REQUIRE(VALID_LENTRY(entry));
int oldrc = isc_refcount_increment(&entry->refcount);
fprintf(stderr, "INCREF %d %p\n", __LINE__, entry, oldrc);
RUNTIME_CHECK(oldrc > 0);
if (entry->remq_enqueued) {
/* This entry is being removed, bail */
isc_refcount_decrement(&entry->refcount);
fprintf(stderr, "DECREF %d %p\n", __LINE__, entry);
return (ISC_R_NOTFOUND);
}
isc_time_t now;
@@ -418,6 +465,8 @@ dns_lowac_get(dns_lowac_t *lowac, dns_name_t *name, unsigned char *blob,
isc_mem_get(lowac->mctx,
(sizeof(ck_fifo_mpmc_entry_t)));
entry->remq_enqueued = true;
isc_refcount_increment(&entry->rqrefcount);
fprintf(stderr, "XXXenq %p %d\n", entry, __LINE__);
ck_fifo_mpmc_enqueue(&lowac->remq, qentry, entry);
return (ISC_R_NOTFOUND);
}
@@ -431,6 +480,7 @@ dns_lowac_get(dns_lowac_t *lowac, dns_name_t *name, unsigned char *blob,
*blobsize = entry->blobsize;
}
isc_refcount_decrement(&entry->refcount);
fprintf(stderr, "DECREF %d %p\n", __LINE__, entry);
return (ISC_R_SUCCESS);
}
return (ISC_R_FAILURE);