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-rw-r--r--trace2/tr2_dst.c84
-rw-r--r--trace2/tr2_sysenv.c3
-rw-r--r--trace2/tr2_sysenv.h2
3 files changed, 89 insertions, 0 deletions
diff --git a/trace2/tr2_dst.c b/trace2/tr2_dst.c
index c698575..a88c466 100644
--- a/trace2/tr2_dst.c
+++ b/trace2/tr2_dst.c
@@ -8,6 +8,19 @@
*/
#define MAX_AUTO_ATTEMPTS 10
+/*
+ * Sentinel file used to detect when we should discard new traces to avoid
+ * writing too many trace files to a directory.
+ */
+#define DISCARD_SENTINEL_NAME "git-trace2-discard"
+
+/*
+ * When set to zero, disables directory file count checks. Otherwise, controls
+ * how many files we can write to a directory before entering discard mode.
+ * This can be overridden via the TR2_SYSENV_MAX_FILES setting.
+ */
+static int tr2env_max_files = 0;
+
static int tr2_dst_want_warning(void)
{
static int tr2env_dst_debug = -1;
@@ -32,6 +45,67 @@ void tr2_dst_trace_disable(struct tr2_dst *dst)
dst->need_close = 0;
}
+/*
+ * Check to make sure we're not overloading the target directory with too many
+ * files. First get the threshold (if present) from the config or envvar. If
+ * it's zero or unset, disable this check. Next check for the presence of a
+ * sentinel file, then check file count. If we are overloaded, create the
+ * sentinel file if it doesn't already exist.
+ *
+ * We expect that some trace processing system is gradually collecting files
+ * from the target directory; after it removes the sentinel file we'll start
+ * writing traces again.
+ */
+static int tr2_dst_too_many_files(const char *tgt_prefix)
+{
+ int file_count = 0, max_files = 0, ret = 0;
+ const char *max_files_var;
+ DIR *dirp;
+ struct strbuf path = STRBUF_INIT, sentinel_path = STRBUF_INIT;
+ struct stat statbuf;
+
+ /* Get the config or envvar and decide if we should continue this check */
+ max_files_var = tr2_sysenv_get(TR2_SYSENV_MAX_FILES);
+ if (max_files_var && *max_files_var && ((max_files = atoi(max_files_var)) >= 0))
+ tr2env_max_files = max_files;
+
+ if (!tr2env_max_files) {
+ ret = 0;
+ goto cleanup;
+ }
+
+ strbuf_addstr(&path, tgt_prefix);
+ if (!is_dir_sep(path.buf[path.len - 1])) {
+ strbuf_addch(&path, '/');
+ }
+
+ /* check sentinel */
+ strbuf_addbuf(&sentinel_path, &path);
+ strbuf_addstr(&sentinel_path, DISCARD_SENTINEL_NAME);
+ if (!stat(sentinel_path.buf, &statbuf)) {
+ ret = 1;
+ goto cleanup;
+ }
+
+ /* check file count */
+ dirp = opendir(path.buf);
+ while (file_count < tr2env_max_files && dirp && readdir(dirp))
+ file_count++;
+ if (dirp)
+ closedir(dirp);
+
+ if (file_count >= tr2env_max_files) {
+ creat(sentinel_path.buf, 0666);
+ ret = 1;
+ goto cleanup;
+ }
+
+cleanup:
+ strbuf_release(&path);
+ strbuf_release(&sentinel_path);
+ return ret;
+}
+
static int tr2_dst_try_auto_path(struct tr2_dst *dst, const char *tgt_prefix)
{
int fd;
@@ -50,6 +124,16 @@ static int tr2_dst_try_auto_path(struct tr2_dst *dst, const char *tgt_prefix)
strbuf_addstr(&path, sid);
base_path_len = path.len;
+ if (tr2_dst_too_many_files(tgt_prefix)) {
+ strbuf_release(&path);
+ if (tr2_dst_want_warning())
+ warning("trace2: not opening %s trace file due to too "
+ "many files in target directory %s",
+ tr2_sysenv_display_name(dst->sysenv_var),
+ tgt_prefix);
+ return 0;
+ }
+
for (attempt_count = 0; attempt_count < MAX_AUTO_ATTEMPTS; attempt_count++) {
if (attempt_count > 0) {
strbuf_setlen(&path, base_path_len);
diff --git a/trace2/tr2_sysenv.c b/trace2/tr2_sysenv.c
index 5958cfc..3c3792e 100644
--- a/trace2/tr2_sysenv.c
+++ b/trace2/tr2_sysenv.c
@@ -49,6 +49,9 @@ static struct tr2_sysenv_entry tr2_sysenv_settings[] = {
"trace2.perftarget" },
[TR2_SYSENV_PERF_BRIEF] = { "GIT_TRACE2_PERF_BRIEF",
"trace2.perfbrief" },
+
+ [TR2_SYSENV_MAX_FILES] = { "GIT_TRACE2_MAX_FILES",
+ "trace2.maxfiles" },
};
/* clang-format on */
diff --git a/trace2/tr2_sysenv.h b/trace2/tr2_sysenv.h
index 8dd82a7..d4364a7 100644
--- a/trace2/tr2_sysenv.h
+++ b/trace2/tr2_sysenv.h
@@ -24,6 +24,8 @@ enum tr2_sysenv_variable {
TR2_SYSENV_PERF,
TR2_SYSENV_PERF_BRIEF,
+ TR2_SYSENV_MAX_FILES,
+
TR2_SYSENV_MUST_BE_LAST
};