spin.c includes pg_sema.h even if unnecessary - Mailing list pgsql-hackers

From Kyotaro HORIGUCHI
Subject spin.c includes pg_sema.h even if unnecessary
Date
Msg-id 20180215.201107.78574525.horiguchi.kyotaro@lab.ntt.co.jp
Whole thread Raw
Responses Re: spin.c includes pg_sema.h even if unnecessary  (Andres Freund <andres@anarazel.de>)
List pgsql-hackers
Ouch! Sorry for the bogus subject of just-submitted mail.
I'll make another thread with the fixed subject.

====
Hello.

As in another mail just before, spin.c seems a bit strange
(without acutual harm).

spin.h doesn't include pg_sema.h when HAVE_SPINLOCKS is defined,
but spin.c always includes it even in the case. The file is
included only to use sizeof(PGSemaphore) to calcualte
SpinlockSemaSize as 0.

The codes that requires PGSempaphore is inactivated when the
symbol is defined in all other places so it seems to me that we
ought to refrain from using it there, too. The attched patch does
that.

regards,

-- 
Kyotaro Horiguchi
NTT Open Source Software Center
diff --git a/src/backend/storage/lmgr/spin.c b/src/backend/storage/lmgr/spin.c
index 6d59a7f..353a3a9 100644
--- a/src/backend/storage/lmgr/spin.c
+++ b/src/backend/storage/lmgr/spin.c
@@ -22,13 +22,15 @@
  */
 #include "postgres.h"
 
-#include "storage/pg_sema.h"
 #include "storage/shmem.h"
 #include "storage/spin.h"
 
 
 #ifndef HAVE_SPINLOCKS
+#define RequredShmemSize (SpinlockSemas() * sizeof(PGSemaphore))
 PGSemaphore *SpinlockSemaArray;
+#else
+#define RequiredShmemSize 0
 #endif
 
 /*
@@ -38,7 +40,7 @@ PGSemaphore *SpinlockSemaArray;
 Size
 SpinlockSemaSize(void)
 {
-    return SpinlockSemas() * sizeof(PGSemaphore);
+    return RequiredShmemSize;
 }
 
 #ifdef HAVE_SPINLOCKS

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