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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2018-11-07 12:19:29 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2018-11-07 12:20:17 +0000 |
commit | a64a253794ac64cb40befee54db53bde17dd0d49 (patch) | |
tree | c1024acc5f6e508814b944d99f112259bb28b1be /web/server/web_client_cache.c | |
parent | New upstream version 1.10.0+dfsg (diff) | |
download | netdata-upstream/1.11.0+dfsg.tar.xz netdata-upstream/1.11.0+dfsg.zip |
New upstream version 1.11.0+dfsgupstream/1.11.0+dfsg
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | web/server/web_client_cache.c | 231 |
1 files changed, 231 insertions, 0 deletions
diff --git a/web/server/web_client_cache.c b/web/server/web_client_cache.c new file mode 100644 index 000000000..ab470560e --- /dev/null +++ b/web/server/web_client_cache.c @@ -0,0 +1,231 @@ +// SPDX-License-Identifier: GPL-3.0-or-later + +#define WEB_SERVER_INTERNALS 1 +#include "web_client_cache.h" + +// ---------------------------------------------------------------------------- +// allocate and free web_clients + +static void web_client_zero(struct web_client *w) { + // zero everything about it - but keep the buffers + + // remember the pointers to the buffers + BUFFER *b1 = w->response.data; + BUFFER *b2 = w->response.header; + BUFFER *b3 = w->response.header_output; + + // empty the buffers + buffer_flush(b1); + buffer_flush(b2); + buffer_flush(b3); + + freez(w->user_agent); + + // zero everything + memset(w, 0, sizeof(struct web_client)); + + // restore the pointers of the buffers + w->response.data = b1; + w->response.header = b2; + w->response.header_output = b3; +} + +static void web_client_free(struct web_client *w) { + buffer_free(w->response.header_output); + buffer_free(w->response.header); + buffer_free(w->response.data); + freez(w->user_agent); + freez(w); +} + +static struct web_client *web_client_alloc(void) { + struct web_client *w = callocz(1, sizeof(struct web_client)); + w->response.data = buffer_create(NETDATA_WEB_RESPONSE_INITIAL_SIZE); + w->response.header = buffer_create(NETDATA_WEB_RESPONSE_HEADER_SIZE); + w->response.header_output = buffer_create(NETDATA_WEB_RESPONSE_HEADER_SIZE); + return w; +} + +// ---------------------------------------------------------------------------- +// web clients caching + +// When clients connect and disconnect, avoid allocating and releasing memory. +// Instead, when new clients get connected, reuse any memory previously allocated +// for serving web clients that are now disconnected. + +// The size of the cache is adaptive. It caches the structures of 2x +// the number of currently connected clients. + +// Comments per server: +// SINGLE-THREADED : 1 cache is maintained +// MULTI-THREADED : 1 cache is maintained +// STATIC-THREADED : 1 cache for each thred of the web server + +__thread struct clients_cache web_clients_cache = { + .pid = 0, + .used = NULL, + .used_count = 0, + .avail = NULL, + .avail_count = 0, + .allocated = 0, + .reused = 0 +}; + +inline void web_client_cache_verify(int force) { +#ifdef NETDATA_INTERNAL_CHECKS + static __thread size_t count = 0; + count++; + + if(unlikely(force || count > 1000)) { + count = 0; + + struct web_client *w; + size_t used = 0, avail = 0; + for(w = web_clients_cache.used; w ; w = w->next) used++; + for(w = web_clients_cache.avail; w ; w = w->next) avail++; + + info("web_client_cache has %zu (%zu) used and %zu (%zu) available clients, allocated %zu, reused %zu (hit %zu%%)." + , used, web_clients_cache.used_count + , avail, web_clients_cache.avail_count + , web_clients_cache.allocated + , web_clients_cache.reused + , (web_clients_cache.allocated + web_clients_cache.reused)?(web_clients_cache.reused * 100 / (web_clients_cache.allocated + web_clients_cache.reused)):0 + ); + } +#else + if(unlikely(force)) { + info("web_client_cache has %zu used and %zu available clients, allocated %zu, reused %zu (hit %zu%%)." + , web_clients_cache.used_count + , web_clients_cache.avail_count + , web_clients_cache.allocated + , web_clients_cache.reused + , (web_clients_cache.allocated + web_clients_cache.reused)?(web_clients_cache.reused * 100 / (web_clients_cache.allocated + web_clients_cache.reused)):0 + ); + } +#endif +} + +// destroy the cache and free all the memory it uses +void web_client_cache_destroy(void) { +#ifdef NETDATA_INTERNAL_CHECKS + if(unlikely(web_clients_cache.pid != 0 && web_clients_cache.pid != gettid())) + error("Oops! wrong thread accessing the cache. Expected %d, found %d", (int)web_clients_cache.pid, (int)gettid()); + + web_client_cache_verify(1); +#endif + + netdata_thread_disable_cancelability(); + + struct web_client *w, *t; + + w = web_clients_cache.used; + while(w) { + t = w; + w = w->next; + web_client_free(t); + } + web_clients_cache.used = NULL; + web_clients_cache.used_count = 0; + + w = web_clients_cache.avail; + while(w) { + t = w; + w = w->next; + web_client_free(t); + } + web_clients_cache.avail = NULL; + web_clients_cache.avail_count = 0; + + netdata_thread_enable_cancelability(); +} + +struct web_client *web_client_get_from_cache_or_allocate() { + +#ifdef NETDATA_INTERNAL_CHECKS + if(unlikely(web_clients_cache.pid == 0)) + web_clients_cache.pid = gettid(); + + if(unlikely(web_clients_cache.pid != 0 && web_clients_cache.pid != gettid())) + error("Oops! wrong thread accessing the cache. Expected %d, found %d", (int)web_clients_cache.pid, (int)gettid()); +#endif + + netdata_thread_disable_cancelability(); + + struct web_client *w = web_clients_cache.avail; + + if(w) { + // get it from avail + if (w == web_clients_cache.avail) web_clients_cache.avail = w->next; + if(w->prev) w->prev->next = w->next; + if(w->next) w->next->prev = w->prev; + web_clients_cache.avail_count--; + web_client_zero(w); + web_clients_cache.reused++; + } + else { + // allocate it + w = web_client_alloc(); + web_clients_cache.allocated++; + } + + // link it to used web clients + if (web_clients_cache.used) web_clients_cache.used->prev = w; + w->next = web_clients_cache.used; + w->prev = NULL; + web_clients_cache.used = w; + web_clients_cache.used_count++; + + // initialize it + w->id = web_client_connected(); + w->mode = WEB_CLIENT_MODE_NORMAL; + + netdata_thread_enable_cancelability(); + + return w; +} + +void web_client_release(struct web_client *w) { +#ifdef NETDATA_INTERNAL_CHECKS + if(unlikely(web_clients_cache.pid != 0 && web_clients_cache.pid != gettid())) + error("Oops! wrong thread accessing the cache. Expected %d, found %d", (int)web_clients_cache.pid, (int)gettid()); + + if(unlikely(w->running)) + error("%llu: releasing web client from %s port %s, but it still running.", w->id, w->client_ip, w->client_port); +#endif + + debug(D_WEB_CLIENT_ACCESS, "%llu: Closing web client from %s port %s.", w->id, w->client_ip, w->client_port); + + web_server_log_connection(w, "DISCONNECTED"); + web_client_request_done(w); + web_client_disconnected(); + + netdata_thread_disable_cancelability(); + + if(web_server_mode != WEB_SERVER_MODE_STATIC_THREADED) { + if (w->ifd != -1) close(w->ifd); + if (w->ofd != -1 && w->ofd != w->ifd) close(w->ofd); + w->ifd = w->ofd = -1; + } + + // unlink it from the used + if (w == web_clients_cache.used) web_clients_cache.used = w->next; + if(w->prev) w->prev->next = w->next; + if(w->next) w->next->prev = w->prev; + web_clients_cache.used_count--; + + if(web_clients_cache.avail_count >= 2 * web_clients_cache.used_count) { + // we have too many of them - free it + web_client_free(w); + } + else { + // link it to the avail + if (web_clients_cache.avail) web_clients_cache.avail->prev = w; + w->next = web_clients_cache.avail; + w->prev = NULL; + web_clients_cache.avail = w; + web_clients_cache.avail_count++; + } + + netdata_thread_enable_cancelability(); +} + |