http: maintain curl sessions

Allow curl sessions to be kept alive (ie. not ended with
curl_easy_cleanup()) even after the request is completed, the number of
which is determined by the configuration setting http.minSessions.

Add a count for curl sessions, and update it, across slots, when
starting and ending curl sessions.

Signed-off-by: Tay Ray Chuan <rctay89@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/config.txt b/Documentation/config.txt
index a8e0876a2add7bb53d3194b1f5e0a2031dd19a42..b77d66da25bfb098c84f249cde721734e04b1b9d 100644 (file)
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -1132,6 +1132,12 @@ http.maxRequests::
        How many HTTP requests to launch in parallel. Can be overridden
        by the 'GIT_HTTP_MAX_REQUESTS' environment variable. Default is 5.
 
+http.minSessions::
+       The number of curl sessions (counted across slots) to be kept across
+       requests. They will not be ended with curl_easy_cleanup() until
+       http_cleanup() is invoked. If USE_CURL_MULTI is not defined, this
+       value will be capped at 1. Defaults to 1.
+
 http.postBuffer::
        Maximum size in bytes of the buffer used by smart HTTP
        transports when POSTing data to the remote system.

diff --git a/http.c b/http.c
index ed6414a2aaa4e0f6cf7672a089f49060aad62bfb..fb0a97b3f9a49da1d21330cb35054698109a695f 100644 (file)
--- a/http.c
+++ b/http.c
@@ -7,6 +7,8 @@ int active_requests;
 int http_is_verbose;
 size_t http_post_buffer = 16 * LARGE_PACKET_MAX;
 
+static int min_curl_sessions = 1;
+static int curl_session_count;
 #ifdef USE_CURL_MULTI
 static int max_requests = -1;
 static CURLM *curlm;
@@ -152,6 +154,14 @@ static int http_options(const char *var, const char *value, void *cb)
                        ssl_cert_password_required = 1;
                return 0;
        }
+       if (!strcmp("http.minsessions", var)) {
+               min_curl_sessions = git_config_int(var, value);
+#ifndef USE_CURL_MULTI
+               if (min_curl_sessions > 1)
+                       min_curl_sessions = 1;
+#endif
+               return 0;
+       }
 #ifdef USE_CURL_MULTI
        if (!strcmp("http.maxrequests", var)) {
                max_requests = git_config_int(var, value);
@@ -372,6 +382,7 @@ void http_init(struct remote *remote)
        if (curl_ssl_verify == -1)
                curl_ssl_verify = 1;
 
+       curl_session_count = 0;
 #ifdef USE_CURL_MULTI
        if (max_requests < 1)
                max_requests = DEFAULT_MAX_REQUESTS;
@@ -480,6 +491,7 @@ struct active_request_slot *get_active_slot(void)
 #else
                slot->curl = curl_easy_duphandle(curl_default);
 #endif
+               curl_session_count++;
        }
 
        active_requests++;
@@ -558,9 +570,11 @@ void fill_active_slots(void)
        }
 
        while (slot != NULL) {
-               if (!slot->in_use && slot->curl != NULL) {
+               if (!slot->in_use && slot->curl != NULL
+                       && curl_session_count > min_curl_sessions) {
                        curl_easy_cleanup(slot->curl);
                        slot->curl = NULL;
+                       curl_session_count--;
                }
                slot = slot->next;
        }
@@ -633,12 +647,13 @@ static void closedown_active_slot(struct active_request_slot *slot)
 void release_active_slot(struct active_request_slot *slot)
 {
        closedown_active_slot(slot);
-       if (slot->curl) {
+       if (slot->curl && curl_session_count > min_curl_sessions) {
 #ifdef USE_CURL_MULTI
                curl_multi_remove_handle(curlm, slot->curl);
 #endif
                curl_easy_cleanup(slot->curl);
                slot->curl = NULL;
+               curl_session_count--;
        }
 #ifdef USE_CURL_MULTI
        fill_active_slots();