From c7f578f6a2163b37a7279bcfb6812e3735c689bd Mon Sep 17 00:00:00 2001
From: Ilya Orlov <iorlov@rzn.dlink.ru>
Date: Sat, 11 Jun 2022 19:47:56 +0300
Subject: [PATCH] [GC] Added option to collect garbage before timeout expires

---
 src/lj_api.c | 66 ++++++++++++++++++++++++++++++++++++++++++++++++++--
 src/lj_str.c |  2 +-
 2 files changed, 65 insertions(+), 3 deletions(-)

diff --git a/src/lj_api.c b/src/lj_api.c
index 8b00436d9b..c9a714c8bc 100644
--- a/src/lj_api.c
+++ b/src/lj_api.c
@@ -26,6 +26,63 @@
 #include "lj_strscan.h"
 #include "lj_strfmt.h"
 
+#include <time.h>
+#if LJ_TARGET_POSIX
+#include <sys/time.h>
+#elif LJ_TARGET_WINDOWS
+#define timercmp(a, b, CMP)                              \
+  (((a)->tv_sec == (b)->tv_sec) ?                        \
+   ((a)->tv_nsec CMP (b)->tv_nsec) :                    \
+   ((a)->tv_sec CMP (b)->tv_sec))
+#define timeradd(a, b, result)                                   \
+  do {                                                                         \
+    (result)->tv_sec = (a)->tv_sec + (b)->tv_sec;         \
+    (result)->tv_nsec = (a)->tv_nsec + (b)->tv_nsec;    \
+    if ((result)->tv_nsec >= 1000000000)                \
+      {                                                 \
+        ++(result)->tv_sec;                             \
+        (result)->tv_nsec -= 1000000000;                \
+      }                                                 \
+  } while (0)
+#endif
+
+static void gc_step_timeout(lua_State *L, uint32_t timeout_usec)
+{
+#if LJ_TARGET_POSIX
+  struct timeval tv_timeout;
+  tv_timeout.tv_sec = 0;
+  tv_timeout.tv_usec = timeout_usec;
+
+  struct timeval tv_current;
+  gettimeofday(&tv_current, NULL);
+
+  timeradd(&tv_current, &tv_timeout, &tv_timeout);
+  while (timercmp(&tv_current, &tv_timeout, <)) {
+    if (lj_gc_step(L) > 0) {
+      break;
+    }
+
+    gettimeofday(&tv_current, NULL);
+  }
+#elif LJ_TARGET_WINDOWS
+  struct timespec tv_timeout;
+  tv_timeout.tv_sec = 0;
+  tv_timeout.tv_nsec = timeout_usec * 1000;
+
+  struct timespec tv_current;
+  timespec_get(&tv_current, TIME_UTC);
+
+  timeradd(&tv_current, &tv_timeout, &tv_timeout);
+  while (timercmp(&tv_current, &tv_timeout, < )) {
+    if (lj_gc_step(L) > 0) {
+      break;
+    }
+
+    timespec_get(&tv_current, TIME_UTC);
+  }
+#endif
+}
+
 /* -- Common helper functions --------------------------------------------- */
 
 #define lj_checkapi_slot(idx) \
@@ -1299,11 +1356,16 @@ LUA_API int lua_gc(lua_State *L, int what, int data)
     g->gc.threshold = (a <= g->gc.total) ? (g->gc.total - a) : 0;
     while (g->gc.total >= g->gc.threshold)
       if (lj_gc_step(L) > 0) {
-	res = 1;
-	break;
+        res = 1;
+        break;
       }
     break;
   }
+  case LUA_GCTIMEOUT: {
+    gc_step_timeout(L, (uint32_t)data);
+    g->gc.threshold = LJ_MAX_MEM;
+    break;
+  }
   case LUA_GCSETPAUSE:
     res = (int)(g->gc.pause);
     g->gc.pause = (MSize)data;
diff --git a/src/lj_str.c b/src/lj_str.c
index f02f2e0f01..a4407fbe6b 100644
--- a/src/lj_str.c
+++ b/src/lj_str.c
@@ -153,7 +153,7 @@ GCstr *lj_str_new(lua_State *L, const char *str, size_t lenx)
   if (LJ_LIKELY((((uintptr_t)str+len-1) & (LJ_PAGESIZE-1)) <= LJ_PAGESIZE-4)) {
     while (o != NULL) {
       GCstr *sx = gco2str(o);
-      if (sx->len == len && str_fastcmp(str, strdata(sx), len) == 0) {
+      if (sx->len == len && strncmp(str, strdata(sx), len) == 0) {
 	/* Resurrect if dead. Can only happen with fixstring() (keywords). */
 	if (isdead(g, o)) flipwhite(o);
 	return sx;  /* Return existing string. */