Add palloc_extended for frontend and backend.

This commit also adds pg_malloc_extended for frontend. These interfaces
can be used to control at a lower level memory allocation using an interface
similar to MemoryContextAllocExtended. For example, the callers can specify
MCXT_ALLOC_NO_OOM if they want to suppress the "out of memory" error while
allocating the memory and handle a NULL return value.

Michael Paquier, reviewed by me.

1 files changed, 15 insertions, 1 deletions

diff --git a/src/include/common/fe_memutils.h b/src/include/common/fe_memutils.h
index db7cb3e3318..51f12eb8251 100644
--- a/src/include/common/fe_memutils.h
+++ b/src/include/common/fe_memutils.h
@@ -9,10 +9,23 @@
 #ifndef FE_MEMUTILS_H
 #define FE_MEMUTILS_H
 
-/* "Safe" memory allocation functions --- these exit(1) on failure */
+/*
+ * Flags for pg_malloc_extended and palloc_extended, deliberately named
+ * the same as the backend flags.
+ */
+#define MCXT_ALLOC_HUGE			0x01	/* allow huge allocation (> 1 GB)
+										 * not actually used for frontends */
+#define MCXT_ALLOC_NO_OOM		0x02	/* no failure if out-of-memory */
+#define MCXT_ALLOC_ZERO			0x04	/* zero allocated memory */
+
+/*
+ * "Safe" memory allocation functions --- these exit(1) on failure
+ * (except pg_malloc_extended with MCXT_ALLOC_NO_OOM)
+ */
 extern char *pg_strdup(const char *in);
 extern void *pg_malloc(size_t size);
 extern void *pg_malloc0(size_t size);
+extern void *pg_malloc_extended(size_t size, int flags);
 extern void *pg_realloc(void *pointer, size_t size);
 extern void pg_free(void *pointer);
 
@@ -20,6 +33,7 @@ extern void pg_free(void *pointer);
 extern char *pstrdup(const char *in);
 extern void *palloc(Size size);
 extern void *palloc0(Size size);
+extern void *palloc_extended(Size size, int flags);
 extern void *repalloc(void *pointer, Size size);
 extern void pfree(void *pointer);