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1931. [bug] Per-client mctx could require a huge amount of memory,

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particularly for a busy caching server. [RT #15519]
This commit is contained in:
Mark Andrews
2005-10-16 23:21:25 +00:00
parent 984d4cc894
commit d08c5dfcd4
2 changed files with 78 additions and 19 deletions
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3
CHANGES
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@@ -1,4 +1,5 @@
1931. [placeholder] rt15519
1931. [bug] Per-client mctx could require a huge amount of memory,
particularly for a busy caching server. [RT #15519]
1930. [port] HPUX: ia64 support. [RT #15473]

94
bin/named/client.c
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@@ -15,7 +15,7 @@
* PERFORMANCE OF THIS SOFTWARE.
*/
/* $Id: client.c,v 1.231 2005/09/28 04:50:15 marka Exp $ */
/* $Id: client.c,v 1.232 2005/10/16 23:21:25 marka Exp $ */
#include <config.h>
@@ -90,6 +90,24 @@
#define SEND_BUFFER_SIZE 4096
#define RECV_BUFFER_SIZE 4096
#ifdef ISC_PLATFORM_USETHREADS
#define NMCTXS 100
/*%<
* Number of 'mctx pools' for clients. (Should this be configurable?)
* When enabling threads, we use a pool of memory contexts shared by
* client objects, since concurrent access to a shared context would cause
* heavy contentions. The above constant is expected to be enough for
* completely avoiding contentions among threads for an authoritative-only
* server.
*/
#else
#define NMCTXS 0
/*%<
* If named with built without thread, simply share manager's context. Using
* a separate context in this case would simply waste memory.
*/
#endif
/*% nameserver client manager structure */
struct ns_clientmgr {
/* Unlocked. */
@@ -103,6 +121,11 @@ struct ns_clientmgr {
client_list_t active; /*%< Active clients */
client_list_t recursing; /*%< Recursing clients */
client_list_t inactive; /*%< To be recycled */
#if NMCTXS > 0
/*%< mctx pool for clients. */
unsigned int nextmctx;
isc_mem_t * mctxpool[NMCTXS];
#endif
};
#define MANAGER_MAGIC ISC_MAGIC('N', 'S', 'C', 'm')
@@ -1674,6 +1697,38 @@ client_timeout(isc_task_t *task, isc_event_t *event) {
(void)exit_check(client);
}
static isc_result_t
get_clientmctx(ns_clientmgr_t *manager, isc_mem_t **mctxp) {
isc_mem_t *clientmctx;
#if NMCTX > 0
isc_result_t result;
#endif
/*
* Caller must be holding the manager lock.
*/
#if NMCTX > 0
INSIST(manager->nextmctx < NMCTXS);
clientmctx = manager->mctxpool[manager->nextmctx];
if (clientmctx == NULL) {
result = isc_mem_create(0, 0, &clientmctx);
if (result != ISC_R_SUCCESS)
return (result);
manager->mctxpool[manager->nextmctx] = clientmctx;
manager->nextmctx++;
if (manager->nextmctx == NMCTXS)
manager->nextmctx = 0;
}
#else
clientmctx = manager->mctx;
#endif
isc_mem_attach(clientmctx, mctxp);
return (ISC_R_SUCCESS);
}
static isc_result_t
client_create(ns_clientmgr_t *manager, ns_client_t **clientp) {
ns_client_t *client;
@@ -1690,25 +1745,9 @@ client_create(ns_clientmgr_t *manager, ns_client_t **clientp) {
REQUIRE(clientp != NULL && *clientp == NULL);
#ifdef ISC_PLATFORM_USETHREADS
/*
* When enabling threads, we use a separate memory context for each
* client, since concurrent access to a shared context would cause
* heavy contentions. We also specify the NOLOCK flag on creation,
* since we are very sure that multiple threads will never get access
* to the context simultaneously.
*/
result = isc_mem_create2(0, 0, &mctx,
ISC_MEMFLAG_DEFAULT | ISC_MEMFLAG_NOLOCK);
result = get_clientmctx(manager, &mctx);
if (result != ISC_R_SUCCESS)
return (result);
#else
/*
* Otherwise, simply share manager's context. Using a separate context
* in this case would simply waste memory.
*/
isc_mem_attach(manager->mctx, &mctx);
#endif
client = isc_mem_get(mctx, sizeof(*client));
if (client == NULL) {
@@ -2106,12 +2145,23 @@ ns_client_replace(ns_client_t *client) {
static void
clientmgr_destroy(ns_clientmgr_t *manager) {
#if NMCTXS > 0
int i;
#endif
REQUIRE(ISC_LIST_EMPTY(manager->active));
REQUIRE(ISC_LIST_EMPTY(manager->inactive));
REQUIRE(ISC_LIST_EMPTY(manager->recursing));
MTRACE("clientmgr_destroy");
#if NMCTXS > 0
for (i = 0; i < NMCTXS; i++) {
if (manager->mctxpool[i] != NULL)
isc_mem_detach(&manager->mctxpool[i]);
}
#endif
DESTROYLOCK(&manager->lock);
manager->magic = 0;
isc_mem_put(manager->mctx, manager, sizeof(*manager));
@@ -2123,6 +2173,9 @@ ns_clientmgr_create(isc_mem_t *mctx, isc_taskmgr_t *taskmgr,
{
ns_clientmgr_t *manager;
isc_result_t result;
#if NMCTXS > 0
int i;
#endif
manager = isc_mem_get(mctx, sizeof(*manager));
if (manager == NULL)
@@ -2139,6 +2192,11 @@ ns_clientmgr_create(isc_mem_t *mctx, isc_taskmgr_t *taskmgr,
ISC_LIST_INIT(manager->active);
ISC_LIST_INIT(manager->inactive);
ISC_LIST_INIT(manager->recursing);
#if NMCTXS > 0
manager->nextmctx = 0;
for (i = 0; i < NMCTXS; i++)
manager->mctxpool[i] = NULL; /* will be created on-demand */
#endif
manager->magic = MANAGER_MAGIC;
MTRACE("create");