[PATCH] misc: Use allocate_once in getmntent
Florian Weimer
fweimer@redhat.com
Wed Aug 21 14:41:00 GMT 2019
Both the buffer and struct mntent are now allocated on the heap.
This results in a slight reduction of RSS usage.
2019-08-21 Florian Weimer <fweimer@redhat.com>
* misc/mntent.c (struct mntent_buffer): Define.
(mntent_buffer): Adjust type to void *.
(allocate): Adjust for allocate_once.
(deallocate): New function.
(getmntent): Call allocate_once.
diff --git a/misc/mntent.c b/misc/mntent.c
index 980ea40967..8fae6064c6 100644
--- a/misc/mntent.c
+++ b/misc/mntent.c
@@ -18,36 +18,41 @@
#include <mntent.h>
#include <stdlib.h>
-#include <libc-lock.h>
+#include <allocate_once.h>
+
+struct mntent_buffer
+{
+ struct mntent m;
+ char buffer[4096];
+};
/* We don't want to allocate the static buffer all the time since it
- is not always used (in fact, rather infrequently). Accept the
- extra cost of a `malloc'. */
-libc_freeres_ptr (static char *getmntent_buffer);
-
-/* This is the size of the buffer. This is really big. */
-#define BUFFER_SIZE 4096
+ is not always used (in fact, rather infrequently). */
+libc_freeres_ptr (static void *mntent_buffer);
+static void *
+allocate (void *closure)
+{
+ return malloc (sizeof (struct mntent_buffer));
+}
static void
-allocate (void)
+deallocate (void *closure, void *ptr)
{
- getmntent_buffer = (char *) malloc (BUFFER_SIZE);
+ free (ptr);
}
-
struct mntent *
getmntent (FILE *stream)
{
- static struct mntent m;
- __libc_once_define (static, once);
- __libc_once (once, allocate);
-
- if (getmntent_buffer == NULL)
+ struct mntent_buffer *buffer = allocate_once (&mntent_buffer,
+ allocate, deallocate, NULL);
+ if (buffer == NULL)
/* If no core is available we don't have a chance to run the
program successfully and so returning NULL is an acceptable
result. */
return NULL;
- return __getmntent_r (stream, &m, getmntent_buffer, BUFFER_SIZE);
+ return __getmntent_r (stream, &buffer->m,
+ buffer->buffer, sizeof (buffer->buffer));
}
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