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Make some minor improvements in memory-context infrastructure.

2022年10月14日 15:55:56 +0000 (11:55 -0400)

We lack a version of repalloc() that supports MCXT_ALLOC_NO_OOM
semantics, so invent repalloc_extended() with the usual set of
flags. repalloc_huge() becomes a legacy wrapper for that.

Also, fix dynahash.c so that it can support HASH_ENTER_NULL
requests when using the default palloc-based allocator.
The only reason it didn't do that already was the lack of the
MCXT_ALLOC_NO_OOM option when that code was written, ages ago.

While here, simplify a few overcomplicated tests in mcxt.c.

Discussion: https://postgr.es/m/2982579.1662416866@sss.pgh.pa.us

src/backend/utils/hash/dynahash.c patch | blob | blame | history

src/backend/utils/mmgr/mcxt.c patch | blob | blame | history

src/include/utils/palloc.h patch | blob | blame | history

diff --git a/src/backend/utils/hash/dynahash.c b/src/backend/utils/hash/dynahash.c

index 3babde8d704db76c7a785792101df405dca45dc3..4f62958883569e23e7d736f80fbc1f5a9fe3ed5a 100644 (file)

--- a/src/backend/utils/hash/dynahash.c

+++ b/src/backend/utils/hash/dynahash.c

@@ -289,7 +289,8 @@ static void *

DynaHashAlloc(Size size)

{

Assert(MemoryContextIsValid(CurrentDynaHashCxt));

- return MemoryContextAlloc(CurrentDynaHashCxt, size);

+ return MemoryContextAllocExtended(CurrentDynaHashCxt, size,

+ MCXT_ALLOC_NO_OOM);

}

@@ -939,9 +940,7 @@ calc_bucket(HASHHDR *hctl, uint32 hash_val)

* HASH_ENTER will normally ereport a generic "out of memory" error if

* it is unable to create a new entry. The HASH_ENTER_NULL operation is

- * the same except it will return NULL if out of memory. Note that

- * HASH_ENTER_NULL cannot be used with the default palloc-based allocator,

- * since palloc internally ereports on out-of-memory.

+ * the same except it will return NULL if out of memory.

* If foundPtr isn't NULL, then *foundPtr is set true if we found an

* existing entry in the table, false otherwise. This is needed in the

@@ -1084,12 +1083,8 @@ hash_search_with_hash_value(HTAB *hashp,

}

return NULL;

- case HASH_ENTER_NULL:

- /* ENTER_NULL does not work with palloc-based allocator */

- Assert(hashp->alloc != DynaHashAlloc);

- /* FALL THRU */

case HASH_ENTER:

+ case HASH_ENTER_NULL:

/* Return existing element if found, else create one */

if (currBucket != NULL)

return (void *) ELEMENTKEY(currBucket);

diff --git a/src/backend/utils/mmgr/mcxt.c b/src/backend/utils/mmgr/mcxt.c

index b1a3c74830575f452a7be169202c15da93d42ec6..012517be5c5f07c8f52ac0658edbd252c2ab19f3 100644 (file)

--- a/src/backend/utils/mmgr/mcxt.c

+++ b/src/backend/utils/mmgr/mcxt.c

@@ -1114,8 +1114,8 @@ MemoryContextAllocExtended(MemoryContext context, Size size, int flags)

AssertArg(MemoryContextIsValid(context));

AssertNotInCriticalSection(context);

- if (((flags & MCXT_ALLOC_HUGE) != 0 && !AllocHugeSizeIsValid(size)) ||

- ((flags & MCXT_ALLOC_HUGE) == 0 && !AllocSizeIsValid(size)))

+ if (!((flags & MCXT_ALLOC_HUGE) != 0 ? AllocHugeSizeIsValid(size) :

+ AllocSizeIsValid(size)))

elog(ERROR, "invalid memory alloc request size %zu", size);

context->isReset = false;

@@ -1269,8 +1269,8 @@ palloc_extended(Size size, int flags)

AssertArg(MemoryContextIsValid(context));

AssertNotInCriticalSection(context);

- if (((flags & MCXT_ALLOC_HUGE) != 0 && !AllocHugeSizeIsValid(size)) ||

- ((flags & MCXT_ALLOC_HUGE) == 0 && !AllocSizeIsValid(size)))

+ if (!((flags & MCXT_ALLOC_HUGE) != 0 ? AllocHugeSizeIsValid(size) :

+ AllocSizeIsValid(size)))

elog(ERROR, "invalid memory alloc request size %zu", size);

context->isReset = false;

@@ -1351,6 +1351,50 @@ repalloc(void *pointer, Size size)

return ret;

}

+/*

+ * repalloc_extended

+ * Adjust the size of a previously allocated chunk,

+ * with HUGE and NO_OOM options.

+ */

+void *

+repalloc_extended(void *pointer, Size size, int flags)

+#if defined(USE_ASSERT_CHECKING) || defined(USE_VALGRIND)

+ MemoryContext context = GetMemoryChunkContext(pointer);

+#endif

+ void *ret;

+ if (!((flags & MCXT_ALLOC_HUGE) != 0 ? AllocHugeSizeIsValid(size) :

+ AllocSizeIsValid(size)))

+ elog(ERROR, "invalid memory alloc request size %zu", size);

+ AssertNotInCriticalSection(context);

+ /* isReset must be false already */

+ Assert(!context->isReset);

+ ret = MCXT_METHOD(pointer, realloc) (pointer, size);

+ if (unlikely(ret == NULL))

+ {

+ if ((flags & MCXT_ALLOC_NO_OOM) == 0)

+ {

+ MemoryContext cxt = GetMemoryChunkContext(pointer);

+ MemoryContextStats(TopMemoryContext);

+ ereport(ERROR,

+ (errcode(ERRCODE_OUT_OF_MEMORY),

+ errmsg("out of memory"),

+ errdetail("Failed on request of size %zu in memory context \"%s\".",

+ size, cxt->name)));

+ }

+ return NULL;

+ }

+ VALGRIND_MEMPOOL_CHANGE(context, pointer, ret, size);

+ return ret;

* MemoryContextAllocHuge

* Allocate (possibly-expansive) space within the specified context.

@@ -1394,35 +1438,8 @@ MemoryContextAllocHuge(MemoryContext context, Size size)

void *

repalloc_huge(void *pointer, Size size)

{

-#if defined(USE_ASSERT_CHECKING) || defined(USE_VALGRIND)

- MemoryContext context = GetMemoryChunkContext(pointer);

-#endif

- void *ret;

- if (!AllocHugeSizeIsValid(size))

- elog(ERROR, "invalid memory alloc request size %zu", size);

- AssertNotInCriticalSection(context);

- /* isReset must be false already */

- Assert(!context->isReset);

- ret = MCXT_METHOD(pointer, realloc) (pointer, size);

- if (unlikely(ret == NULL))

- {

- MemoryContext cxt = GetMemoryChunkContext(pointer);

- MemoryContextStats(TopMemoryContext);

- ereport(ERROR,

- (errcode(ERRCODE_OUT_OF_MEMORY),

- errmsg("out of memory"),

- errdetail("Failed on request of size %zu in memory context \"%s\".",

- size, cxt->name)));

- }

- VALGRIND_MEMPOOL_CHANGE(context, pointer, ret, size);

- return ret;

+ /* this one seems not worth its own implementation */

+ return repalloc_extended(pointer, size, MCXT_ALLOC_HUGE);

}

diff --git a/src/include/utils/palloc.h b/src/include/utils/palloc.h

index a0b62aa7b0c7179d7188c0cbd9fd7f33e626032d..8eee0e293857ca839a40487dbd8220c74509293d 100644 (file)

--- a/src/include/utils/palloc.h

+++ b/src/include/utils/palloc.h

@@ -78,6 +78,8 @@ extern void *palloc(Size size);

extern void *palloc0(Size size);

extern void *palloc_extended(Size size, int flags);

extern pg_nodiscard void *repalloc(void *pointer, Size size);

+extern pg_nodiscard void *repalloc_extended(void *pointer,

+ Size size, int flags);

extern void pfree(void *pointer);

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