From: drh <drh@noemail.net>
Date: Sat, 5 Aug 2017 15:49:03 +0000 (+0000)
Subject: Microoptimization in pcache1.c makes the code slightly smaller and faster.
X-Git-Tag: version-3.21.0~186
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=eabb67fb6175d83f54b8039b49bee4f25782e4c6;p=thirdparty%2Fsqlite.git

Microoptimization in pcache1.c makes the code slightly smaller and faster.

FossilOrigin-Name: 422cd9f39403feeacd70133c7a147e23572c75d617ac564344f016ae6611162c
---

diff --git a/manifest b/manifest
index 323396404b..647ccf3274 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Fix\smemory\sleak\sin\sswarmvtab.
-D 2017-08-05T15:30:46.798
+C Microoptimization\sin\spcache1.c\smakes\sthe\scode\sslightly\ssmaller\sand\sfaster.
+D 2017-08-05T15:49:03.201
 F Makefile.in d9873c9925917cca9990ee24be17eb9613a668012c85a343aef7e5536ae266e8
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc 02b469e9dcd5b7ee63fc1fb05babc174260ee4cfa4e0ef2e48c3c6801567a016
@@ -444,7 +444,7 @@ F src/pager.h f2a99646c5533ffe11afa43e9e0bea74054e4efa
 F src/parse.y 52ef3cecd0934e9da4a45b585883a03243ad615d338ad94f44501a05891dcdfa
 F src/pcache.c 62835bed959e2914edd26afadfecce29ece0e870
 F src/pcache.h 521bb9610d38ef17a3cc9b5ddafd4546c2ea67fa3d0e464823d73c2a28d50e11
-F src/pcache1.c 1195a21fe28e223e024f900b2011e80df53793f0356a24caace4188b098540dc
+F src/pcache1.c 0b793738b5dddaf0a645784835c6b5557b1ecfaee339af9c26810c6ecdb273aa
 F src/pragma.c cd6aeda3587be6c5c08f9b2d45eae6068666a03c9d077c8c43cdb85fb0aa70f2
 F src/pragma.h bb83728944b42f6d409c77f5838a8edbdb0fe83046c5496ffc9602b40340a324
 F src/prepare.c 3cbb99757d7295997674972f9dd2331c5c544368854ca08954c9beb1e9b6145a
@@ -1642,7 +1642,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 0f6f6f03deaba2f4bdd168980647136e8ddff4907863b62b3056b8e4665599df
-R f365a6808acdb26589f2df261eade4f9
-U dan
-Z 31ef269ee04dd02f63613adcac211879
+P 002a9c7baccf3417c56ec7d16755ea32fdd70a654ffc75f2fc4624fd2b688aed
+R dcb8fc9ec89330fec69c3eee54be505b
+U drh
+Z 2eca10fcc0a16cb9db9d08ac69a27abe
diff --git a/manifest.uuid b/manifest.uuid
index 543cbef5f2..a598b3c9c8 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-002a9c7baccf3417c56ec7d16755ea32fdd70a654ffc75f2fc4624fd2b688aed
\ No newline at end of file
+422cd9f39403feeacd70133c7a147e23572c75d617ac564344f016ae6611162c
\ No newline at end of file
diff --git a/src/pcache1.c b/src/pcache1.c
index fa0c6a79f2..9c59574ace 100644
--- a/src/pcache1.c
+++ b/src/pcache1.c
@@ -96,7 +96,6 @@ typedef struct PGroup PGroup;
 struct PgHdr1 {
   sqlite3_pcache_page page;      /* Base class. Must be first. pBuf & pExtra */
   unsigned int iKey;             /* Key value (page number) */
-  u8 isPinned;                   /* Page in use, not on the LRU list */
   u8 isBulkLocal;                /* This page from bulk local storage */
   u8 isAnchor;                   /* This is the PGroup.lru element */
   PgHdr1 *pNext;                 /* Next in hash table chain */
@@ -105,6 +104,12 @@ struct PgHdr1 {
   PgHdr1 *pLruPrev;              /* Previous in LRU list of unpinned pages */
 };
 
+/*
+** A page is pinned if it is no on the LRU list
+*/
+#define PAGE_IS_PINNED(p)    ((p)->pLruNext==0)
+#define PAGE_IS_UNPINNED(p)  ((p)->pLruNext!=0)
+
 /* Each page cache (or PCache) belongs to a PGroup.  A PGroup is a set 
 ** of one or more PCaches that are able to recycle each other's unpinned
 ** pages when they are under memory pressure.  A PGroup is an instance of
@@ -557,22 +562,18 @@ static void pcache1ResizeHash(PCache1 *p){
 ** The PGroup mutex must be held when this function is called.
 */
 static PgHdr1 *pcache1PinPage(PgHdr1 *pPage){
-  PCache1 *pCache;
-
   assert( pPage!=0 );
-  assert( pPage->isPinned==0 );
-  pCache = pPage->pCache;
+  assert( PAGE_IS_UNPINNED(pPage) );
   assert( pPage->pLruNext );
   assert( pPage->pLruPrev );
-  assert( sqlite3_mutex_held(pCache->pGroup->mutex) );
+  assert( sqlite3_mutex_held(pPage->pCache->pGroup->mutex) );
   pPage->pLruPrev->pLruNext = pPage->pLruNext;
   pPage->pLruNext->pLruPrev = pPage->pLruPrev;
   pPage->pLruNext = 0;
   pPage->pLruPrev = 0;
-  pPage->isPinned = 1;
   assert( pPage->isAnchor==0 );
-  assert( pCache->pGroup->lru.isAnchor==1 );
-  pCache->nRecyclable--;
+  assert( pPage->pCache->pGroup->lru.isAnchor==1 );
+  pPage->pCache->nRecyclable--;
   return pPage;
 }
 
@@ -610,7 +611,7 @@ static void pcache1EnforceMaxPage(PCache1 *pCache){
       && (p=pGroup->lru.pLruPrev)->isAnchor==0
   ){
     assert( p->pCache->pGroup==pGroup );
-    assert( p->isPinned==0 );
+    assert( PAGE_IS_UNPINNED(p) );
     pcache1PinPage(p);
     pcache1RemoveFromHash(p, 1);
   }
@@ -659,7 +660,7 @@ static void pcache1TruncateUnsafe(
       if( pPage->iKey>=iLimit ){
         pCache->nPage--;
         *pp = pPage->pNext;
-        if( !pPage->isPinned ) pcache1PinPage(pPage);
+        if( PAGE_IS_UNPINNED(pPage) ) pcache1PinPage(pPage);
         pcache1FreePage(pPage);
       }else{
         pp = &pPage->pNext;
@@ -878,7 +879,7 @@ static SQLITE_NOINLINE PgHdr1 *pcache1FetchStage2(
   ){
     PCache1 *pOther;
     pPage = pGroup->lru.pLruPrev;
-    assert( pPage->isPinned==0 );
+    assert( PAGE_IS_UNPINNED(pPage) );
     pcache1RemoveFromHash(pPage, 0);
     pcache1PinPage(pPage);
     pOther = pPage->pCache;
@@ -905,7 +906,6 @@ static SQLITE_NOINLINE PgHdr1 *pcache1FetchStage2(
     pPage->pCache = pCache;
     pPage->pLruPrev = 0;
     pPage->pLruNext = 0;
-    pPage->isPinned = 1;
     *(void **)pPage->page.pExtra = 0;
     pCache->apHash[h] = pPage;
     if( iKey>pCache->iMaxKey ){
@@ -991,7 +991,7 @@ static PgHdr1 *pcache1FetchNoMutex(
   ** Otherwise (page not in hash and createFlag!=0) continue with
   ** subsequent steps to try to create the page. */
   if( pPage ){
-    if( !pPage->isPinned ){
+    if( PAGE_IS_UNPINNED(pPage) ){
       return pcache1PinPage(pPage);
     }else{
       return pPage;
@@ -1066,7 +1066,7 @@ static void pcache1Unpin(
   ** part of the PGroup LRU list.
   */
   assert( pPage->pLruPrev==0 && pPage->pLruNext==0 );
-  assert( pPage->isPinned==1 );
+  assert( PAGE_IS_PINNED(pPage) );
 
   if( reuseUnlikely || pGroup->nCurrentPage>pGroup->nMaxPage ){
     pcache1RemoveFromHash(pPage, 1);
@@ -1077,7 +1077,6 @@ static void pcache1Unpin(
     (pPage->pLruNext = *ppFirst)->pLruPrev = pPage;
     *ppFirst = pPage;
     pCache->nRecyclable++;
-    pPage->isPinned = 0;
   }
 
   pcache1LeaveMutex(pCache->pGroup);
@@ -1221,7 +1220,7 @@ int sqlite3PcacheReleaseMemory(int nReq){
 #ifdef SQLITE_PCACHE_SEPARATE_HEADER
       nFree += sqlite3MemSize(p);
 #endif
-      assert( p->isPinned==0 );
+      assert( PAGE_IS_UNPINNED(p) );
       pcache1PinPage(p);
       pcache1RemoveFromHash(p, 1);
     }
@@ -1245,7 +1244,7 @@ void sqlite3PcacheStats(
   PgHdr1 *p;
   int nRecyclable = 0;
   for(p=pcache1.grp.lru.pLruNext; p && !p->isAnchor; p=p->pLruNext){
-    assert( p->isPinned==0 );
+    assert( PAGE_IS_UNPINNED(p) );
     nRecyclable++;
   }
   *pnCurrent = pcache1.grp.nCurrentPage;