diff src/http/ngx_http_file_cache.c @ 7670:ccb5ff87ab3e

Cache: introduced min_free cache clearing. Clearing cache based on free space left on a file system is expected to allow better disk utilization in some cases, notably when disk space might be also used for something other than nginx cache (including nginx own temporary files) and while loading cache (when cache size might be inaccurate for a while, effectively disabling max_size cache clearing). Based on a patch by Adam Bambuch.
author Maxim Dounin <mdounin@mdounin.ru>
date Mon, 22 Jun 2020 18:03:00 +0300
parents bddacdaaec9e
children 847fd35f94de
line wrap: on
line diff
--- a/src/http/ngx_http_file_cache.c
+++ b/src/http/ngx_http_file_cache.c
@@ -1959,7 +1959,7 @@ ngx_http_file_cache_manager(void *data)
 {
     ngx_http_file_cache_t  *cache = data;
 
-    off_t       size;
+    off_t       size, free;
     time_t      wait;
     ngx_msec_t  elapsed, next;
     ngx_uint_t  count, watermark;
@@ -1988,7 +1988,19 @@ ngx_http_file_cache_manager(void *data)
                        size, count, (ngx_int_t) watermark);
 
         if (size < cache->max_size && count < watermark) {
-            break;
+
+            if (!cache->min_free) {
+                break;
+            }
+
+            free = ngx_fs_available(cache->path->name.data);
+
+            ngx_log_debug1(NGX_LOG_DEBUG_HTTP, ngx_cycle->log, 0,
+                           "http file cache free: %O", free);
+
+            if (free > cache->min_free) {
+                break;
+            }
         }
 
         wait = ngx_http_file_cache_forced_expire(cache);
@@ -2304,7 +2316,7 @@ ngx_http_file_cache_set_slot(ngx_conf_t 
 {
     char  *confp = conf;
 
-    off_t                   max_size;
+    off_t                   max_size, min_free;
     u_char                 *last, *p;
     time_t                  inactive;
     ssize_t                 size;
@@ -2341,6 +2353,7 @@ ngx_http_file_cache_set_slot(ngx_conf_t 
     name.len = 0;
     size = 0;
     max_size = NGX_MAX_OFF_T_VALUE;
+    min_free = 0;
 
     value = cf->args->elts;
 
@@ -2476,6 +2489,29 @@ ngx_http_file_cache_set_slot(ngx_conf_t 
             continue;
         }
 
+        if (ngx_strncmp(value[i].data, "min_free=", 9) == 0) {
+
+#if (NGX_WIN32 || NGX_HAVE_STATFS || NGX_HAVE_STATVFS)
+
+            s.len = value[i].len - 9;
+            s.data = value[i].data + 9;
+
+            min_free = ngx_parse_offset(&s);
+            if (min_free < 0) {
+                ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
+                                   "invalid min_free value \"%V\"", &value[i]);
+                return NGX_CONF_ERROR;
+            }
+
+#else
+            ngx_conf_log_error(NGX_LOG_WARN, cf, 0,
+                               "min_free is not supported "
+                               "on this platform, ignored");
+#endif
+
+            continue;
+        }
+
         if (ngx_strncmp(value[i].data, "loader_files=", 13) == 0) {
 
             loader_files = ngx_atoi(value[i].data + 13, value[i].len - 13);
@@ -2607,6 +2643,7 @@ ngx_http_file_cache_set_slot(ngx_conf_t 
 
     cache->inactive = inactive;
     cache->max_size = max_size;
+    cache->min_free = min_free;
 
     caches = (ngx_array_t *) (confp + cmd->offset);