static void MemoryContextStatsInternal()

in src/postgres/src_backend_utils_mmgr_mcxt.c [90:162]

• 20 lines of code
• 2 McCabe index (conditional complexity)

static void MemoryContextStatsInternal(MemoryContext context, int level,
						   bool print, int max_children,
						   MemoryContextCounters *totals);

/*
 * You should not do memory allocations within a critical section, because
 * an out-of-memory error will be escalated to a PANIC. To enforce that
 * rule, the allocation functions Assert that.
 */
#define AssertNotInCriticalSection(context) \
	Assert(CritSectionCount == 0 || (context)->allowInCritSection)

/*****************************************************************************
 *	  EXPORTED ROUTINES														 *
 *****************************************************************************/


/*
 * MemoryContextInit
 *		Start up the memory-context subsystem.
 *
 * This must be called before creating contexts or allocating memory in
 * contexts.  TopMemoryContext and ErrorContext are initialized here;
 * other contexts must be created afterwards.
 *
 * In normal multi-backend operation, this is called once during
 * postmaster startup, and not at all by individual backend startup
 * (since the backends inherit an already-initialized context subsystem
 * by virtue of being forked off the postmaster).  But in an EXEC_BACKEND
 * build, each process must do this for itself.
 *
 * In a standalone backend this must be called during backend startup.
 */
void
MemoryContextInit(void)
{
	AssertState(TopMemoryContext == NULL);

	/*
	 * First, initialize TopMemoryContext, which will hold the MemoryContext
	 * nodes for all other contexts.  (There is special-case code in
	 * MemoryContextCreate() to handle this call.)
	 */
	TopMemoryContext = AllocSetContextCreate((MemoryContext) NULL,
											 "TopMemoryContext",
											 ALLOCSET_DEFAULT_SIZES);

	/*
	 * Not having any other place to point CurrentMemoryContext, make it point
	 * to TopMemoryContext.  Caller should change this soon!
	 */
	CurrentMemoryContext = TopMemoryContext;

	/*
	 * Initialize ErrorContext as an AllocSetContext with slow growth rate ---
	 * we don't really expect much to be allocated in it. More to the point,
	 * require it to contain at least 8K at all times. This is the only case
	 * where retained memory in a context is *essential* --- we want to be
	 * sure ErrorContext still has some memory even if we've run out
	 * elsewhere! Also, allow allocations in ErrorContext within a critical
	 * section. Otherwise a PANIC will cause an assertion failure in the error
	 * reporting code, before printing out the real cause of the failure.
	 *
	 * This should be the last step in this function, as elog.c assumes memory
	 * management works once ErrorContext is non-null.
	 */
	ErrorContext = AllocSetContextCreate(TopMemoryContext,
										 "ErrorContext",
										 8 * 1024,
										 8 * 1024,
										 8 * 1024);
	MemoryContextAllowInCriticalSection(ErrorContext, true);
}