Merge branch 'jk/drop-release-pack-memory'

xmalloc() used to have a mechanism to ditch memory and address
space resources as the last resort upon seeing an allocation
failure from the underlying malloc(), which made the code complex
and thread-unsafe with dubious benefit, as major memory resource
users already do limit their uses with various other mechanisms.
It has been simplified away.

* jk/drop-release-pack-memory:
  packfile: drop release_pack_memory()

builtin/pack-objects.c

@@ -2342,15 +2342,6 @@ static void find_deltas(struct object_entry **list, unsigned *list_size,
 	free(array);
 }
 
-static void try_to_free_from_threads(size_t size)
-{
-	packing_data_lock(&to_pack);
-	release_pack_memory(size);
-	packing_data_unlock(&to_pack);
-}
-
-static try_to_free_t old_try_to_free_routine;
-
 /*
  * The main object list is split into smaller lists, each is handed to
  * one worker.
@@ -2391,12 +2382,10 @@ static void init_threaded_search(void)
 	pthread_mutex_init(&cache_mutex, NULL);
 	pthread_mutex_init(&progress_mutex, NULL);
 	pthread_cond_init(&progress_cond, NULL);
-	old_try_to_free_routine = set_try_to_free_routine(try_to_free_from_threads);
 }
 
 static void cleanup_threaded_search(void)
 {
-	set_try_to_free_routine(old_try_to_free_routine);
 	pthread_cond_destroy(&progress_cond);
 	pthread_mutex_destroy(&cache_mutex);
 	pthread_mutex_destroy(&progress_mutex);

git-compat-util.h

@@ -818,9 +818,6 @@ const char *inet_ntop(int af, const void *src, char *dst, size_t size);
 int git_atexit(void (*handler)(void));
 #endif
 
-typedef void (*try_to_free_t)(size_t);
-try_to_free_t set_try_to_free_routine(try_to_free_t);
-
 static inline size_t st_add(size_t a, size_t b)
 {
 	if (unsigned_add_overflows(a, b))

packfile.c

@@ -287,13 +287,6 @@ static int unuse_one_window(struct packed_git *current)
 	return 0;
 }
 
-void release_pack_memory(size_t need)
-{
-	size_t cur = pack_mapped;
-	while (need >= (cur - pack_mapped) && unuse_one_window(NULL))
-		; /* nothing */
-}
-
 void close_pack_windows(struct packed_git *p)
 {
 	while (p->windows) {
@@ -710,23 +703,12 @@ void unuse_pack(struct pack_window **w_cursor)
 	}
 }
 
-static void try_to_free_pack_memory(size_t size)
-{
-	release_pack_memory(size);
-}
-
 struct packed_git *add_packed_git(const char *path, size_t path_len, int local)
 {
-	static int have_set_try_to_free_routine;
 	struct stat st;
 	size_t alloc;
 	struct packed_git *p;
 
-	if (!have_set_try_to_free_routine) {
-		have_set_try_to_free_routine = 1;
-		set_try_to_free_routine(try_to_free_pack_memory);
-	}
-
 	/*
 	 * Make sure a corresponding .pack file exists and that
 	 * the index looks sane.

sha1-file.c

@@ -952,12 +952,8 @@ void *xmmap_gently(void *start, size_t length,
 
 	mmap_limit_check(length);
 	ret = mmap(start, length, prot, flags, fd, offset);
-	if (ret == MAP_FAILED) {
-		if (!length)
-			return NULL;
-		release_pack_memory(length);
-		ret = mmap(start, length, prot, flags, fd, offset);
-	}
+	if (ret == MAP_FAILED && !length)
+		ret = NULL;
 	return ret;
 }
 

trace.c

@@ -88,8 +88,6 @@ static int prepare_trace_line(const char *file, int line,
 	if (!trace_want(key))
 		return 0;
 
-	set_try_to_free_routine(NULL);	/* is never reset */
-
 	/* unit tests may want to disable additional trace output */
 	if (trace_want(&trace_bare))
 		return 1;

wrapper.c

@@ -4,12 +4,6 @@
 #include "cache.h"
 #include "config.h"
 
-static void do_nothing(size_t size)
-{
-}
-
-static void (*try_to_free_routine)(size_t size) = do_nothing;
-
 static int memory_limit_check(size_t size, int gentle)
 {
 	static size_t limit = 0;
@@ -30,24 +24,11 @@ static int memory_limit_check(size_t size, int gentle)
 	return 0;
 }
 
-try_to_free_t set_try_to_free_routine(try_to_free_t routine)
-{
-	try_to_free_t old = try_to_free_routine;
-	if (!routine)
-		routine = do_nothing;
-	try_to_free_routine = routine;
-	return old;
-}
-
 char *xstrdup(const char *str)
 {
 	char *ret = strdup(str);
-	if (!ret) {
-		try_to_free_routine(strlen(str) + 1);
-		ret = strdup(str);
-		if (!ret)
-			die("Out of memory, strdup failed");
-	}
+	if (!ret)
+		die("Out of memory, strdup failed");
 	return ret;
 }
 
@@ -61,19 +42,13 @@ static void *do_xmalloc(size_t size, int gentle)
 	if (!ret && !size)
 		ret = malloc(1);
 	if (!ret) {
-		try_to_free_routine(size);
-		ret = malloc(size);
-		if (!ret && !size)
-			ret = malloc(1);
-		if (!ret) {
-			if (!gentle)
-				die("Out of memory, malloc failed (tried to allocate %lu bytes)",
-				    (unsigned long)size);
-			else {
-				error("Out of memory, malloc failed (tried to allocate %lu bytes)",
-				      (unsigned long)size);
-				return NULL;
-			}
+		if (!gentle)
+			die("Out of memory, malloc failed (tried to allocate %lu bytes)",
+			    (unsigned long)size);
+		else {
+			error("Out of memory, malloc failed (tried to allocate %lu bytes)",
+			      (unsigned long)size);
+			return NULL;
 		}
 	}
 #ifdef XMALLOC_POISON
@@ -138,14 +113,8 @@ void *xrealloc(void *ptr, size_t size)
 	ret = realloc(ptr, size);
 	if (!ret && !size)
 		ret = realloc(ptr, 1);
-	if (!ret) {
-		try_to_free_routine(size);
-		ret = realloc(ptr, size);
-		if (!ret && !size)
-			ret = realloc(ptr, 1);
-		if (!ret)
-			die("Out of memory, realloc failed");
-	}
+	if (!ret)
+		die("Out of memory, realloc failed");
 	return ret;
 }
 
@@ -160,14 +129,8 @@ void *xcalloc(size_t nmemb, size_t size)
 	ret = calloc(nmemb, size);
 	if (!ret && (!nmemb || !size))
 		ret = calloc(1, 1);
-	if (!ret) {
-		try_to_free_routine(nmemb * size);
-		ret = calloc(nmemb, size);
-		if (!ret && (!nmemb || !size))
-			ret = calloc(1, 1);
-		if (!ret)
-			die("Out of memory, calloc failed");
-	}
+	if (!ret)
+		die("Out of memory, calloc failed");
 	return ret;
 }