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Remove the extra memory context with own arena for sending

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(cherry picked from commit 8d4cc41c291f8a77a723ae8e62533538b3632d50)
This commit is contained in:
Ondřej Surý 2024-06-04 11:21:24 +02:00 committed by Nicki Křížek
parent 3f6b7f57a6
commit 0b1d70ed2a
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GPG key ID: 01623B9B652A20A7
2 changed files with 2 additions and 60 deletions
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61
lib/ns/client.c
View file

@ -354,7 +354,7 @@ client_put_tcp_buffer(ns_client_t *client) {
}
if (client->tcpbuf != client->manager->tcp_buffer) {
isc_mem_put(client->manager->send_mctx, client->tcpbuf,
isc_mem_put(client->manager->mctx, client->tcpbuf,
client->tcpbuf_size);
}
@ -419,7 +419,7 @@ client_sendpkg(ns_client_t *client, isc_buffer_t *buffer) {
* correct size and freeing the big buffer.
*/
unsigned char *new_tcpbuf =
isc_mem_get(client->manager->send_mctx, used);
isc_mem_get(client->manager->mctx, used);
memmove(new_tcpbuf, buffer->base, used);
/*
@ -2511,8 +2511,6 @@ clientmgr_destroy(ns_clientmgr_t *manager) {
isc_task_detach(&manager->task);
ns_server_detach(&manager->sctx);
isc_mem_detach(&manager->send_mctx);
isc_mem_putanddetach(&manager->mctx, manager, sizeof(*manager));
}
@ -2549,61 +2547,6 @@ ns_clientmgr_create(ns_server_t *sctx, isc_taskmgr_t *taskmgr,
ISC_LIST_INIT(manager->recursing);
/*
* We create specialised per-worker memory context specifically
* dedicated and tuned for allocating send buffers as it is a very
* common operation. Not doing so may result in excessive memory
* use in certain workloads.
*
* Please see this thread for more details:
*
* https://github.com/jemalloc/jemalloc/issues/2483
*
* In particular, this information from the jemalloc developers is
* of the most interest:
*
* https://github.com/jemalloc/jemalloc/issues/2483#issuecomment-1639019699
* https://github.com/jemalloc/jemalloc/issues/2483#issuecomment-1698173849
*
* In essence, we use the following memory management strategy:
*
* 1. We use a per-worker memory arena for send buffers memory
* allocation to reduce lock contention (In reality, we create a
* per-client manager arena, but we have one client manager per
* worker).
*
* 2. The automatically created arenas settings remain unchanged
* and may be controlled by users (e.g. by setting the
* "MALLOC_CONF" variable).
*
* 3. We attune the arenas to not use dirty pages cache as the
* cache would have a poor reuse rate, and that is known to
* significantly contribute to excessive memory use.
*
* 4. There is no strict need for the dirty cache, as there is a
* per arena bin for each allocation size, so because we initially
* allocate strictly 64K per send buffer (enough for a DNS
* message), allocations would get directed to one bin (an "object
* pool" or a "slab") maintained within an arena. That is, there
* is an object pool already, specifically to optimise for the
* case of frequent allocations of objects of the given size. The
* object pool should suffice our needs, as we will end up
* recycling the objects from there without the need to back it by
* an additional layer of dirty pages cache. The dirty pages cache
* would have worked better in the case when there are more
* allocation bins involved due to a higher reuse rate (the case
* of a more "generic" memory management).
*/
isc_mem_create_arena(&manager->send_mctx);
isc_mem_setname(manager->send_mctx, "sendbufs");
(void)isc_mem_arena_set_dirty_decay_ms(manager->send_mctx, 0);
/*
* Disable muzzy pages cache too, as versions < 5.2.0 have it
* enabled by default. The muzzy pages cache goes right below the
* dirty pages cache and backs it.
*/
(void)isc_mem_arena_set_muzzy_decay_ms(manager->send_mctx, 0);
manager->magic = MANAGER_MAGIC;
MTRACE("create");

1
lib/ns/include/ns/client.h
View file

@ -144,7 +144,6 @@ struct ns_clientmgr {
unsigned int magic;
isc_mem_t *mctx;
isc_mem_t *send_mctx;
ns_server_t *sctx;
isc_taskmgr_t *taskmgr;
isc_timermgr_t *timermgr;