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.
diff --git a/src/http/ngx_http_cache.h b/src/http/ngx_http_cache.h
index f9e9664..cd0b4bb 100644
--- a/src/http/ngx_http_cache.h
+++ b/src/http/ngx_http_cache.h
@@ -160,6 +160,7 @@
ngx_path_t *path;
+ off_t min_free;
off_t max_size;
size_t bsize;
diff --git a/src/http/ngx_http_file_cache.c b/src/http/ngx_http_file_cache.c
index ecdf11e..e985f27 100644
--- a/src/http/ngx_http_file_cache.c
+++ b/src/http/ngx_http_file_cache.c
@@ -1959,7 +1959,7 @@
{
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 @@
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 @@
{
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 @@
name.len = 0;
size = 0;
max_size = NGX_MAX_OFF_T_VALUE;
+ min_free = 0;
value = cf->args->elts;
@@ -2476,6 +2489,29 @@
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 @@
cache->inactive = inactive;
cache->max_size = max_size;
+ cache->min_free = min_free;
caches = (ngx_array_t *) (confp + cmd->offset);
diff --git a/src/os/unix/ngx_files.c b/src/os/unix/ngx_files.c
index 7e8e58f..1c82a8e 100644
--- a/src/os/unix/ngx_files.c
+++ b/src/os/unix/ngx_files.c
@@ -884,6 +884,19 @@
return (size_t) fs.f_bsize;
}
+
+off_t
+ngx_fs_available(u_char *name)
+{
+ struct statfs fs;
+
+ if (statfs((char *) name, &fs) == -1) {
+ return NGX_MAX_OFF_T_VALUE;
+ }
+
+ return (off_t) fs.f_bavail * fs.f_bsize;
+}
+
#elif (NGX_HAVE_STATVFS)
size_t
@@ -908,6 +921,19 @@
return (size_t) fs.f_frsize;
}
+
+off_t
+ngx_fs_available(u_char *name)
+{
+ struct statvfs fs;
+
+ if (statvfs((char *) name, &fs) == -1) {
+ return NGX_MAX_OFF_T_VALUE;
+ }
+
+ return (off_t) fs.f_bavail * fs.f_frsize;
+}
+
#else
size_t
@@ -916,4 +942,11 @@
return 512;
}
+
+off_t
+ngx_fs_available(u_char *name)
+{
+ return NGX_MAX_OFF_T_VALUE;
+}
+
#endif
diff --git a/src/os/unix/ngx_files.h b/src/os/unix/ngx_files.h
index 3e36984..d084713 100644
--- a/src/os/unix/ngx_files.h
+++ b/src/os/unix/ngx_files.h
@@ -349,6 +349,7 @@
#endif
size_t ngx_fs_bsize(u_char *name);
+off_t ngx_fs_available(u_char *name);
#if (NGX_HAVE_OPENAT)
diff --git a/src/os/win32/ngx_files.c b/src/os/win32/ngx_files.c
index 0b131b5..3017b45 100644
--- a/src/os/win32/ngx_files.c
+++ b/src/os/win32/ngx_files.c
@@ -658,6 +658,19 @@
}
+off_t
+ngx_fs_available(u_char *name)
+{
+ ULARGE_INTEGER navail;
+
+ if (GetDiskFreeSpaceEx((const char *) name, &navail, NULL, NULL) == 0) {
+ return NGX_MAX_OFF_T_VALUE;
+ }
+
+ return (off_t) navail.QuadPart;
+}
+
+
static ngx_int_t
ngx_win32_check_filename(u_char *name, u_short *u, size_t len)
{
diff --git a/src/os/win32/ngx_files.h b/src/os/win32/ngx_files.h
index 6eb720e..a10839b 100644
--- a/src/os/win32/ngx_files.h
+++ b/src/os/win32/ngx_files.h
@@ -259,6 +259,7 @@
#define ngx_directio_off_n "ngx_directio_off_n"
size_t ngx_fs_bsize(u_char *name);
+off_t ngx_fs_available(u_char *name);
#define ngx_stdout GetStdHandle(STD_OUTPUT_HANDLE)
