On 2015-08-12 10:18:12 -0400, Tom Lane wrote:
> Andres Freund <and...@anarazel.de> writes:
> > On 2015-07-01 12:55:48 -0300, Alvaro Herrera wrote:
> >> Tom Lane wrote:
> >>> I'm thinking we really ought to mount a campaign to replace some of these
> >>> macros with inlined-if-possible functions.
>
> >> My guess is that changing a very small amount of them will do a large
> >> enough portion of the job.
>
> > I think it'd be good to convert the macros in bufpage.h and bufmgr.h
> > that either currently have multiple evaluation hazards, or have a
> > AssertMacro() in them. The former for obvious reasons, the latter
> > because that immediately makes them rather large (on and it implies
> > multiple evaluation hazards anyway).
>
> > That'd mean inlining PageSetPageSizeAndVersion(), PageGetSpecialSize(),
> > PageGetSpecialPointer(), PageGetItem(), PageGetMaxOffsetNumber(),
> > PageIsPrunable(), PageSetPrunable(), PageClearPrunable(),
> > BufferIsValid(), BufferGetBlock(), BufferGetPageSize().
>
> Sounds reasonable to me. If you do this, I'll see whether pademelon
> can be adjusted to build using the minimum macro expansion buffer
> size specified by the C standard.
Here's the patch attached.
There's two more macros on the list that I had missed:
PageXLogRecPtrSet(), PageXLogRecPtrGet(). Unfortunately *Set() requires
to pas a pointer to the PageXLogRecPtr - there's only two callers tho.
We could instead just leave these, or add an indirecting macro. Seems
fine to me though.
With it applied pg compiles without the warning I saw before:
/home/andres/src/postgresql/src/backend/access/brin/brin_pageops.c:778:5:
warning: string literal of length 7732 exceeds maximum length 4095
that ISO C99 compilers are required to support [-Woverlength-strings]
Assert(BRIN_IS_REGULAR_PAGE(BufferGetPage(oldbuf)));
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We could obviously be more aggressive and convert all the applicable
defines, but they are already readable and have no multiple eval
hazards, so I'm not inclined to that.
Andres
>From 8203fd286c276051060a6fe8c98c8b576c644f14 Mon Sep 17 00:00:00 2001
From: Andres Freund <and...@anarazel.de>
Date: Thu, 13 Aug 2015 01:37:44 +0200
Subject: [PATCH] Change some buffer and page related macros to inline
functions.
Firstly some of these macros could recursively expand to string literals
larger than the minimum required to be supported by an environment by
the C standard. That's primarily due to included assertions. Secondly
some macros had multiple evaluation hazards.
This required one minor API change in that PageXLogRecPtrSet now takes a
pointer to a PageXLogRecPtr instead the value directly. There shouldn't
be callers to it out there...
Discussion: 4407.1435763...@sss.pgh.pa.us
---
src/include/access/gist.h | 2 +-
src/include/storage/bufmgr.h | 29 +++++-----
src/include/storage/bufpage.h | 124 ++++++++++++++++++++++++++----------------
3 files changed, 95 insertions(+), 60 deletions(-)
diff --git a/src/include/access/gist.h b/src/include/access/gist.h
index 81e559b..33eb9d3 100644
--- a/src/include/access/gist.h
+++ b/src/include/access/gist.h
@@ -142,7 +142,7 @@ typedef struct GISTENTRY
#define GistClearFollowRight(page) ( GistPageGetOpaque(page)->flags &= ~F_FOLLOW_RIGHT)
#define GistPageGetNSN(page) ( PageXLogRecPtrGet(GistPageGetOpaque(page)->nsn))
-#define GistPageSetNSN(page, val) ( PageXLogRecPtrSet(GistPageGetOpaque(page)->nsn, val))
+#define GistPageSetNSN(page, val) ( PageXLogRecPtrSet(&GistPageGetOpaque(page)->nsn, val))
/*
* Vector of GISTENTRY structs; user-defined methods union and picksplit
diff --git a/src/include/storage/bufmgr.h b/src/include/storage/bufmgr.h
index ec0a254..235264c 100644
--- a/src/include/storage/bufmgr.h
+++ b/src/include/storage/bufmgr.h
@@ -96,11 +96,12 @@ extern PGDLLIMPORT int32 *LocalRefCount;
* even in non-assert-enabled builds can be significant. Thus, we've
* now demoted the range checks to assertions within the macro itself.
*/
-#define BufferIsValid(bufnum) \
-( \
- AssertMacro((bufnum) <= NBuffers && (bufnum) >= -NLocBuffer), \
- (bufnum) != InvalidBuffer \
-)
+static inline bool
+BufferIsValid(Buffer bufnum)
+{
+ AssertArg(bufnum <= NBuffers && bufnum >= -NLocBuffer);
+ return bufnum != InvalidBuffer;
+}
/*
* BufferGetBlock
@@ -109,14 +110,16 @@ extern PGDLLIMPORT int32 *LocalRefCount;
* Note:
* Assumes buffer is valid.
*/
-#define BufferGetBlock(buffer) \
-( \
- AssertMacro(BufferIsValid(buffer)), \
- BufferIsLocal(buffer) ? \
- LocalBufferBlockPointers[-(buffer) - 1] \
- : \
- (Block) (BufferBlocks + ((Size) ((buffer) - 1)) * BLCKSZ) \
-)
+static inline Block
+BufferGetBlock(Buffer buffer)
+{
+ AssertArg(BufferIsValid(buffer));
+
+ if (BufferIsLocal(buffer))
+ return LocalBufferBlockPointers[-buffer - 1];
+ else
+ return (Block) (BufferBlocks + ((Size) (buffer - 1)) * BLCKSZ);
+}
/*
* BufferGetPageSize
diff --git a/src/include/storage/bufpage.h b/src/include/storage/bufpage.h
index a2f78ee..4d104b8 100644
--- a/src/include/storage/bufpage.h
+++ b/src/include/storage/bufpage.h
@@ -14,6 +14,7 @@
#ifndef BUFPAGE_H
#define BUFPAGE_H
+#include "access/transam.h"
#include "access/xlogdefs.h"
#include "storage/block.h"
#include "storage/item.h"
@@ -93,10 +94,18 @@ typedef struct
uint32 xrecoff; /* low bits */
} PageXLogRecPtr;
-#define PageXLogRecPtrGet(val) \
- ((uint64) (val).xlogid << 32 | (val).xrecoff)
-#define PageXLogRecPtrSet(ptr, lsn) \
- ((ptr).xlogid = (uint32) ((lsn) >> 32), (ptr).xrecoff = (uint32) (lsn))
+static inline XLogRecPtr
+PageXLogRecPtrGet(PageXLogRecPtr pageptr)
+{
+ return ((uint64) pageptr.xlogid) << 32 | pageptr.xrecoff;
+}
+
+static inline void
+PageXLogRecPtrSet(PageXLogRecPtr *pageptr, XLogRecPtr lsn)
+{
+ pageptr->xlogid = (uint32) (lsn >> 32);
+ pageptr->xrecoff = (uint32) lsn;
+}
/*
* disk page organization
@@ -197,7 +206,7 @@ typedef PageHeaderData *PageHeader;
#define PG_DATA_CHECKSUM_VERSION 1
/* ----------------------------------------------------------------
- * page support macros
+ * page support macros & inline functions
* ----------------------------------------------------------------
*/
@@ -279,12 +288,13 @@ typedef PageHeaderData *PageHeader;
* We could support setting these two values separately, but there's
* no real need for it at the moment.
*/
-#define PageSetPageSizeAndVersion(page, size, version) \
-( \
- AssertMacro(((size) & 0xFF00) == (size)), \
- AssertMacro(((version) & 0x00FF) == (version)), \
- ((PageHeader) (page))->pd_pagesize_version = (size) | (version) \
-)
+static inline void
+PageSetPageSizeAndVersion(Page page, Size size, int version)
+{
+ Assert((size & 0xFF00) == size);
+ Assert((version & 0x00FF) == version);
+ ((PageHeader) page)->pd_pagesize_version = size | version;
+}
/* ----------------
* page special data macros
@@ -294,20 +304,26 @@ typedef PageHeaderData *PageHeader;
* PageGetSpecialSize
* Returns size of special space on a page.
*/
-#define PageGetSpecialSize(page) \
- ((uint16) (PageGetPageSize(page) - ((PageHeader)(page))->pd_special))
+static inline uint16
+PageGetSpecialSize(Page page)
+{
+ return (uint16) (PageGetPageSize(page) - ((PageHeader) page)->pd_special);
+}
/*
* PageGetSpecialPointer
* Returns pointer to special space on a page.
*/
-#define PageGetSpecialPointer(page) \
-( \
- AssertMacro(PageIsValid(page)), \
- AssertMacro(((PageHeader) (page))->pd_special <= BLCKSZ), \
- AssertMacro(((PageHeader) (page))->pd_special >= SizeOfPageHeaderData), \
- (char *) ((char *) (page) + ((PageHeader) (page))->pd_special) \
-)
+static inline char *
+PageGetSpecialPointer(Page page)
+{
+ PageHeader ph = (PageHeader) page;
+
+ Assert(PageIsValid(page));
+ Assert(ph->pd_special <= BLCKSZ);
+ Assert(ph->pd_special >= SizeOfPageHeaderData);
+ return ((char *) page) + ph->pd_special;
+}
/*
* PageGetItem
@@ -317,12 +333,13 @@ typedef PageHeaderData *PageHeader;
* This does not change the status of any of the resources passed.
* The semantics may change in the future.
*/
-#define PageGetItem(page, itemId) \
-( \
- AssertMacro(PageIsValid(page)), \
- AssertMacro(ItemIdHasStorage(itemId)), \
- (Item)(((char *)(page)) + ItemIdGetOffset(itemId)) \
-)
+static inline Item
+PageGetItem(Page page, ItemId itemId)
+{
+ Assert(PageIsValid(page));
+ Assert(ItemIdHasStorage(itemId));
+ return (Item)(((char *) page) + ItemIdGetOffset(itemId));
+}
/*
* PageGetMaxOffsetNumber
@@ -334,19 +351,24 @@ typedef PageHeaderData *PageHeader;
* return zero to ensure sane behavior. Accept double evaluation
* of the argument so that we can ensure this.
*/
-#define PageGetMaxOffsetNumber(page) \
- (((PageHeader) (page))->pd_lower <= SizeOfPageHeaderData ? 0 : \
- ((((PageHeader) (page))->pd_lower - SizeOfPageHeaderData) \
- / sizeof(ItemIdData)))
+static inline LocationIndex
+PageGetMaxOffsetNumber(Page page)
+{
+ PageHeader ph = (PageHeader) page;
+
+ if (ph->pd_lower <= SizeOfPageHeaderData)
+ return 0;
+ else
+ return (ph->pd_lower - SizeOfPageHeaderData) / sizeof(ItemIdData);
+}
/*
- * Additional macros for access to page headers. (Beware multiple evaluation
- * of the arguments!)
+ * Additional page header accessors
*/
#define PageGetLSN(page) \
PageXLogRecPtrGet(((PageHeader) (page))->pd_lsn)
#define PageSetLSN(page, lsn) \
- PageXLogRecPtrSet(((PageHeader) (page))->pd_lsn, lsn)
+ PageXLogRecPtrSet(&((PageHeader) (page))->pd_lsn, lsn)
#define PageHasFreeLinePointers(page) \
(((PageHeader) (page))->pd_flags & PD_HAS_FREE_LINES)
@@ -369,19 +391,29 @@ typedef PageHeaderData *PageHeader;
#define PageClearAllVisible(page) \
(((PageHeader) (page))->pd_flags &= ~PD_ALL_VISIBLE)
-#define PageIsPrunable(page, oldestxmin) \
-( \
- AssertMacro(TransactionIdIsNormal(oldestxmin)), \
- TransactionIdIsValid(((PageHeader) (page))->pd_prune_xid) && \
- TransactionIdPrecedes(((PageHeader) (page))->pd_prune_xid, oldestxmin) \
-)
-#define PageSetPrunable(page, xid) \
-do { \
- Assert(TransactionIdIsNormal(xid)); \
- if (!TransactionIdIsValid(((PageHeader) (page))->pd_prune_xid) || \
- TransactionIdPrecedes(xid, ((PageHeader) (page))->pd_prune_xid)) \
- ((PageHeader) (page))->pd_prune_xid = (xid); \
-} while (0)
+static inline bool
+PageIsPrunable(Page page, TransactionId oldestxmin)
+{
+ TransactionId prune_xid = ((PageHeader) page)->pd_prune_xid;
+
+ Assert(TransactionIdIsNormal(oldestxmin));
+
+ return TransactionIdIsValid(prune_xid) &&
+ TransactionIdPrecedes(prune_xid, oldestxmin);
+}
+
+static inline void
+PageSetPrunable(Page page, TransactionId xid)
+{
+ PageHeader ph = (PageHeader) page;
+
+ Assert(TransactionIdIsNormal(xid));
+
+ if (!TransactionIdIsValid(ph->pd_prune_xid) ||
+ TransactionIdPrecedes(xid, ph->pd_prune_xid))
+ ph->pd_prune_xid = xid;
+}
+
#define PageClearPrunable(page) \
(((PageHeader) (page))->pd_prune_xid = InvalidTransactionId)
--
2.3.0.149.gf3f4077.dirty
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