This is a debug patch which is only to be used while the lstat_cache()
is in the test stage, and should be removed/reverted before the final
relase.
I think it should be useful to catch these warnings, as I it could be
an indication of that the cache would not be very effective if it is
doing ping-pong by switching between different cache types too many
times.
Also, if someone is experimenting with the lstat_cache(), this patch
will maybe be useful while debugging.
If someone is able to trigger the warning, then send a mail to the GIT
mailing list, containing the first 15 lines of the warning, and a
short description of the GIT commands to trigger the warnings.
I hope someone is willing to use this patch for a while, to be able to
catch possible ping-pong's.
Signed-off-by: Kjetil Barvik <barvik@xxxxxxxxxxxx>
---
symlinks.c | 23 +++++++++++++++++++++++
1 files changed, 23 insertions(+), 0 deletions(-)
diff --git a/symlinks.c b/symlinks.c
index ae57e56..fe4b188 100644
--- a/symlinks.c
+++ b/symlinks.c
@@ -51,6 +51,11 @@ static inline void reset_lstat_cache(void)
*/
}
+#define SWITCHES_BEFORE_WARNING 10
+static unsigned int cache_switches, number_of_warnings;
+static unsigned int current_cache_func, last_cache_func;
+static unsigned int total_calls;
+
#define FL_DIR (1 << 0)
#define FL_NOENT (1 << 1)
#define FL_SYMLINK (1 << 2)
@@ -77,6 +82,7 @@ static int lstat_cache(int len, const char *name,
int match_flags, ret_flags, save_flags, max_len, ret;
struct stat st;
+ total_calls++;
if (cache.track_flags != track_flags ||
cache.prefix_len_stat_func != prefix_len_stat_func) {
/*
@@ -88,6 +94,17 @@ static int lstat_cache(int len, const char *name,
cache.track_flags = track_flags;
cache.prefix_len_stat_func = prefix_len_stat_func;
match_len = last_slash = 0;
+ cache_switches++;
+ if (cache_switches > SWITCHES_BEFORE_WARNING) {
+ if (number_of_warnings < 10 || number_of_warnings % 1000 == 0)
+ printf("warning from %s:%d cache_switches:%u > %u "\
+ "(current:%u last:%u total:%u)\n",
+ __FILE__, __LINE__,
+ cache_switches, SWITCHES_BEFORE_WARNING,
+ current_cache_func, last_cache_func,
+ total_calls);
+ number_of_warnings++;
+ }
} else {
/*
* Check to see if we have a match from the cache for
@@ -214,6 +231,8 @@ void clear_lstat_cache(void)
*/
int has_symlink_leading_path(int len, const char *name)
{
+ last_cache_func = current_cache_func;
+ current_cache_func = 1;
return lstat_cache(len, name,
FL_SYMLINK|FL_DIR, USE_ONLY_LSTAT) &
FL_SYMLINK;
@@ -225,6 +244,8 @@ int has_symlink_leading_path(int len, const char *name)
*/
int has_symlink_or_noent_leading_path(int len, const char *name)
{
+ last_cache_func = current_cache_func;
+ current_cache_func = 2;
return lstat_cache(len, name,
FL_SYMLINK|FL_NOENT|FL_DIR, USE_ONLY_LSTAT) &
(FL_SYMLINK|FL_NOENT);
@@ -239,6 +260,8 @@ int has_symlink_or_noent_leading_path(int len, const char *name)
*/
int has_dirs_only_path(int len, const char *name, int prefix_len)
{
+ last_cache_func = current_cache_func;
+ current_cache_func = 3;
return lstat_cache(len, name,
FL_DIR|FL_FULLPATH, prefix_len) &
FL_DIR;
--
1.6.1.349.g99fa5
--
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