greenplumn mcxt 源码
greenplumn mcxt 代码
文件路径：/src/backend/utils/mmgr/mcxt.c
/*-------------------------------------------------------------------------
*
* mcxt.c
* POSTGRES memory context management code.
*
* This module handles context management operations that are independent
* of the particular kind of context being operated on. It calls
* context-type-specific operations via the function pointers in a
* context's MemoryContextMethods struct.
*
*
* Portions Copyright (c) 2007-2008, Greenplum inc
* Portions Copyright (c) 2012-Present VMware, Inc. or its affiliates.
* Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/backend/utils/mmgr/mcxt.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "mb/pg_wchar.h"
#include "miscadmin.h"
#include "utils/memdebug.h"
#include "utils/memutils.h"
#include "cdb/cdbvars.h" /* coredump_on_memerror */
#include "inttypes.h"
#ifdef CDB_PALLOC_CALLER_ID
#define CDB_MCXT_WHERE(context) (context)->callerFile, (context)->callerLine
#else
#define CDB_MCXT_WHERE(context) __FILE__, __LINE__
#endif
#if defined(CDB_PALLOC_TAGS) && !defined(CDB_PALLOC_CALLER_ID)
#error "If CDB_PALLOC_TAGS is defined, CDB_PALLOC_CALLER_ID must be defined too"
#endif
/*****************************************************************************
* GLOBAL MEMORY *
*****************************************************************************/
/*
* CurrentMemoryContext
* Default memory context for allocations.
*/
MemoryContext CurrentMemoryContext = NULL;
/*
* Standard top-level contexts. For a description of the purpose of each
* of these contexts, refer to src/backend/utils/mmgr/README
*/
MemoryContext TopMemoryContext = NULL;
MemoryContext ErrorContext = NULL;
MemoryContext PostmasterContext = NULL;
MemoryContext CacheMemoryContext = NULL;
MemoryContext MessageContext = NULL;
MemoryContext TopTransactionContext = NULL;
MemoryContext CurTransactionContext = NULL;
MemoryContext DispatcherContext = NULL;
MemoryContext InterconnectContext = NULL;
MemoryContext OptimizerMemoryContext = NULL;
/* This is a transient link to the active portal's memory context: */
MemoryContext PortalContext = NULL;
static void MemoryContextCallResetCallbacks(MemoryContext context);
static void MemoryContextStatsInternal(MemoryContext context, int level,
bool print, int max_children,
MemoryContextCounters *totals);
static void MemoryContextStatsPrint(MemoryContext context, void *passthru,
const char *stats_string);
/*
* 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.
*/
/*
* GPDB_94_MERGE_FIXME: Disabled temporarily, we were unsafe things in GPDB.
* Fix all the failures and re-enable this later.
*/
#if 0
#define AssertNotInCriticalSection(context) \
Assert(CritSectionCount == 0 || (context)->allowInCritSection)
#else
#define AssertNotInCriticalSection(context)
#endif
/*****************************************************************************
* 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 is the parent of all others.
*/
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);
}
/*
* MemoryContextReset
* Release all space allocated within a context and delete all its
* descendant contexts (but not the named context itself).
*/
void
MemoryContextReset(MemoryContext context)
{
AssertArg(MemoryContextIsValid(context));
/* save a function call in common case where there are no children */
if (context->firstchild != NULL)
MemoryContextDeleteChildren(context);
/* save a function call if no pallocs since startup or last reset */
if (!context->isReset)
MemoryContextResetOnly(context);
}
/*
* MemoryContextResetOnly
* Release all space allocated within a context.
* Nothing is done to the context's descendant contexts.
*/
void
MemoryContextResetOnly(MemoryContext context)
{
AssertArg(MemoryContextIsValid(context));
/* Nothing to do if no pallocs since startup or last reset */
if (!context->isReset)
{
MemoryContextCallResetCallbacks(context);
/*
* If context->ident points into the context's memory, it will become
* a dangling pointer. We could prevent that by setting it to NULL
* here, but that would break valid coding patterns that keep the
* ident elsewhere, e.g. in a parent context. Another idea is to use
* MemoryContextContains(), but we don't require ident strings to be
* in separately-palloc'd chunks, so that risks false positives. So
* for now we assume the programmer got it right.
*/
context->methods->reset(context);
context->isReset = true;
VALGRIND_DESTROY_MEMPOOL(context);
VALGRIND_CREATE_MEMPOOL(context, 0, false);
}
}
/*
* MemoryContextResetChildren
* Release all space allocated within a context's descendants,
* but don't delete the contexts themselves. The named context
* itself is not touched.
*/
void
MemoryContextResetChildren(MemoryContext context)
{
MemoryContext child;
AssertArg(MemoryContextIsValid(context));
for (child = context->firstchild; child != NULL; child = child->nextchild)
{
MemoryContextResetChildren(child);
MemoryContextResetOnly(child);
}
}
/*
* MemoryContextDelete
* Delete a context and its descendants, and release all space
* allocated therein.
*
* The type-specific delete routine removes all storage for the context,
* but we have to recurse to handle the children.
* We must also delink the context from its parent, if it has one.
*/
void
MemoryContextDeleteImpl(MemoryContext context, const char* sfile, const char *func, int sline)
{
MemoryContext parent;
AssertArg(MemoryContextIsValid(context));
/* We had better not be deleting TopMemoryContext ... */
Assert(context != TopMemoryContext);
/* And not CurrentMemoryContext, either */
Assert(context != CurrentMemoryContext);
#ifdef CDB_PALLOC_CALLER_ID
context->callerFile = sfile;
context->callerLine = sline;
#endif
/* save a function call in common case where there are no children */
if (context->firstchild != NULL)
MemoryContextDeleteChildren(context);
/*
* It's not entirely clear whether 'tis better to do this before or after
* delinking the context; but an error in a callback will likely result in
* leaking the whole context (if it's not a root context) if we do it
* after, so let's do it before.
*/
MemoryContextCallResetCallbacks(context);
/*
* We delink the context from its parent before deleting it, so that if
* there's an error we won't have deleted/busted contexts still attached
* to the context tree. Better a leak than a crash.
*/
parent = MemoryContextGetParent(context);
MemoryContextSetParent(context, NULL);
/*
* Also reset the context's ident pointer, in case it points into the
* context. This would only matter if someone tries to get stats on the
* (already unlinked) context, which is unlikely, but let's be safe.
*/
context->ident = NULL;
context->methods->delete_context(context, parent);
VALGRIND_DESTROY_MEMPOOL(context);
}
/*
* MemoryContextDeleteChildren
* Delete all the descendants of the named context and release all
* space allocated therein. The named context itself is not touched.
*/
void
MemoryContextDeleteChildren(MemoryContext context)
{
AssertArg(MemoryContextIsValid(context));
/*
* MemoryContextDelete will delink the child from me, so just iterate as
* long as there is a child.
*/
while (context->firstchild != NULL)
MemoryContextDelete(context->firstchild);
}
/*
* MemoryContextRegisterResetCallback
* Register a function to be called before next context reset/delete.
* Such callbacks will be called in reverse order of registration.
*
* The caller is responsible for allocating a MemoryContextCallback struct
* to hold the info about this callback request, and for filling in the
* "func" and "arg" fields in the struct to show what function to call with
* what argument. Typically the callback struct should be allocated within
* the specified context, since that means it will automatically be freed
* when no longer needed.
*
* There is no API for deregistering a callback once registered. If you
* want it to not do anything anymore, adjust the state pointed to by its
* "arg" to indicate that.
*/
void
MemoryContextRegisterResetCallback(MemoryContext context,
MemoryContextCallback *cb)
{
AssertArg(MemoryContextIsValid(context));
/* Push onto head so this will be called before older registrants. */
cb->next = context->reset_cbs;
context->reset_cbs = cb;
/* Mark the context as non-reset (it probably is already). */
context->isReset = false;
}
/*
* MemoryContextCallResetCallbacks
* Internal function to call all registered callbacks for context.
*/
static void
MemoryContextCallResetCallbacks(MemoryContext context)
{
MemoryContextCallback *cb;
/*
* We pop each callback from the list before calling. That way, if an
* error occurs inside the callback, we won't try to call it a second time
* in the likely event that we reset or delete the context later.
*/
while ((cb = context->reset_cbs) != NULL)
{
context->reset_cbs = cb->next;
cb->func(cb->arg);
}
}
/*
* MemoryContextSetIdentifier
* Set the identifier string for a memory context.
*
* An identifier can be provided to help distinguish among different contexts
* of the same kind in memory context stats dumps. The identifier string
* must live at least as long as the context it is for; typically it is
* allocated inside that context, so that it automatically goes away on
* context deletion. Pass id = NULL to forget any old identifier.
*/
void
MemoryContextSetIdentifier(MemoryContext context, const char *id)
{
AssertArg(MemoryContextIsValid(context));
context->ident = id;
}
/*
* MemoryContextSetParent
* Change a context to belong to a new parent (or no parent).
*
* We provide this as an API function because it is sometimes useful to
* change a context's lifespan after creation. For example, a context
* might be created underneath a transient context, filled with data,
* and then reparented underneath CacheMemoryContext to make it long-lived.
* In this way no special effort is needed to get rid of the context in case
* a failure occurs before its contents are completely set up.
*
* Callers often assume that this function cannot fail, so don't put any
* elog(ERROR) calls in it.
*
* A possible caller error is to reparent a context under itself, creating
* a loop in the context graph. We assert here that context != new_parent,
* but checking for multi-level loops seems more trouble than it's worth.
*/
void
MemoryContextSetParent(MemoryContext context, MemoryContext new_parent)
{
AssertArg(MemoryContextIsValid(context));
AssertArg(context != new_parent);
/* Fast path if it's got correct parent already */
if (new_parent == context->parent)
return;
/* update memory accounting */
AllocSetTransferAccounting(context, new_parent);
/* Delink from existing parent, if any */
if (context->parent)
{
MemoryContext parent = context->parent;
if (context->prevchild != NULL)
context->prevchild->nextchild = context->nextchild;
else
{
Assert(parent->firstchild == context);
parent->firstchild = context->nextchild;
}
if (context->nextchild != NULL)
context->nextchild->prevchild = context->prevchild;
}
/* And relink */
if (new_parent)
{
AssertArg(MemoryContextIsValid(new_parent));
context->parent = new_parent;
context->prevchild = NULL;
context->nextchild = new_parent->firstchild;
if (new_parent->firstchild != NULL)
new_parent->firstchild->prevchild = context;
new_parent->firstchild = context;
}
else
{
context->parent = NULL;
context->prevchild = NULL;
context->nextchild = NULL;
}
}
/*
* MemoryContextAllowInCriticalSection
* Allow/disallow allocations in this memory context within a critical
* section.
*
* Normally, memory allocations are not allowed within a critical section,
* because a failure would lead to PANIC. There are a few exceptions to
* that, like allocations related to debugging code that is not supposed to
* be enabled in production. This function can be used to exempt specific
* memory contexts from the assertion in palloc().
*/
void
MemoryContextAllowInCriticalSection(MemoryContext context, bool allow)
{
AssertArg(MemoryContextIsValid(context));
context->allowInCritSection = allow;
}
/*
* GetMemoryChunkSpace
* Given a currently-allocated chunk, determine the total space
* it occupies (including all memory-allocation overhead).
*
* This is useful for measuring the total space occupied by a set of
* allocated chunks.
*/
Size
GetMemoryChunkSpace(void *pointer)
{
MemoryContext context = GetMemoryChunkContext(pointer);
return context->methods->get_chunk_space(context, pointer);
}
/*
* MemoryContextGetParent
* Get the parent context (if any) of the specified context
*/
MemoryContext
MemoryContextGetParent(MemoryContext context)
{
AssertArg(MemoryContextIsValid(context));
return context->parent;
}
/*
* MemoryContextIsEmpty
* Is a memory context empty of any allocated space?
*/
bool
MemoryContextIsEmpty(MemoryContext context)
{
AssertArg(MemoryContextIsValid(context));
/*
* For now, we consider a memory context nonempty if it has any children;
* perhaps this should be changed later.
*/
if (context->firstchild != NULL)
return false;
/* Otherwise use the type-specific inquiry */
return context->methods->is_empty(context);
}
/*
* MemoryContextError
* Report failure of a memory context operation. Does not return.
*/
void
MemoryContextError(int errorcode, MemoryContext context,
const char *sfile, int sline,
const char *fmt, ...)
{
va_list args;
char buf[200];
/*
* Don't use elog, as we might have a malloc problem.
* Also, don't use write_log, as this method might be
* called from syslogger, which does not support
* write_log calls
*/
write_stderr("Logging memory usage for memory context error");
MemoryContextStats(TopMemoryContext);
if(coredump_on_memerror)
{
/*
* Turn memory context into a SIGSEGV, so will generate
* a core dump.
*
* XXX What is the right way of doing this?
*/
((void(*)()) NULL)();
}
if(errorcode != ERRCODE_OUT_OF_MEMORY && errorcode != ERRCODE_INTERNAL_ERROR)
{
Assert(!"Memory context error: unknown error code.");
}
/* Format caller's message. */
va_start(args, fmt);
vsnprintf(buf, sizeof(buf)-32, fmt, args);
va_end(args);
/*
* This might fail if we run out of memory at the system level
* (i.e., malloc returned null), and the system is running so
* low in memory that ereport cannot format its parameter.
* However, we already dumped our usage information using
* write_stderr, so we are gonna take a chance by calling ereport.
* If we fail, we at least have OOM message in the log. If we succeed,
* we will also have the detail error code and location of the error.
* Note, ereport should switch to ErrorContext which should have
* some preallocated memory to handle this message. Therefore,
* our chance of success is quite high
*/
ereport(ERROR, (errcode(errorcode),
errmsg("%s (context '%s') (%s:%d)",
buf,
context->name,
sfile ? sfile : "",
sline)
));
/* not reached */
abort();
} /* MemoryContextError */
void
MemoryContextDeclareAccountingRoot(MemoryContext context)
{
AssertArg(MemoryContextIsValid(context));
return (*context->methods->declare_accounting_root) (context);
}
/*
* MemoryContextGetCurrentSpace
* Return the number of bytes currently occupied by the memory context.
*
* This is the amount of space obtained from the lower-level source of the
* memory (e.g. malloc) and not yet released back to that source. Includes
* overhead and free space held and managed within this context by the
* context-type-specific memory manager.
*/
Size
MemoryContextGetCurrentSpace(MemoryContext context)
{
AssertArg(MemoryContextIsValid(context));
return (*context->methods->get_current_usage) (context);
} /* MemoryContextGetCurrentSpace */
/*
* MemoryContextGetPeakSpace
* Return the peak number of bytes occupied by the memory context.
*
* This is the maximum value reached by MemoryContextGetCurrentSpace() since
* the context was created, or since reset by MemoryContextSetPeakSpace().
*/
Size
MemoryContextGetPeakSpace(MemoryContext context)
{
AssertArg(MemoryContextIsValid(context));
return (*context->methods->get_peak_usage) (context);
} /* MemoryContextGetPeakSpace */
/*
* MemoryContextSetPeakSpace
* Resets the peak space statistic to the space currently occupied or
* the specified value, whichever is greater. Returns the former peak
* space value.
*
* Can be used to observe local maximum usage over an interval and then to
* restore the overall maximum.
*/
Size
MemoryContextSetPeakSpace(MemoryContext context, Size nbytes)
{
AssertArg(MemoryContextIsValid(context));
return (*context->methods->set_peak_usage) (context, nbytes);
} /* MemoryContextSetPeakSpace */
/*
* Find the memory allocated to blocks for this memory context. If recurse is
* true, also include children.
*/
int64
MemoryContextMemAllocated(MemoryContext context, bool recurse)
{
int64 total = context->mem_allocated;
AssertArg(MemoryContextIsValid(context));
if (recurse)
{
MemoryContext child = context->firstchild;
for (child = context->firstchild;
child != NULL;
child = child->nextchild)
total += MemoryContextMemAllocated(child, true);
}
return total;
}
/*
* MemoryContextStats
* Print statistics about the named context and all its descendants.
*
* This is just a debugging utility, so it's not very fancy. However, we do
* make some effort to summarize when the output would otherwise be very long.
* The statistics are sent to stderr.
*/
void
MemoryContextStats(MemoryContext context)
{
/* A hard-wired limit on the number of children is usually good enough */
MemoryContextStatsDetail(context, 100);
}
/*
* MemoryContextStatsDetail
*
* Entry point for use if you want to vary the number of child contexts shown.
*/
void
MemoryContextStatsDetail(MemoryContext context, int max_children)
{
MemoryContextCounters grand_totals;
memset(&grand_totals, 0, sizeof(grand_totals));
MemoryContextStatsInternal(context, 0, true, max_children, &grand_totals);
fprintf(stderr,
"Grand total: %zu bytes in %zd blocks; %zu free (%zd chunks); %zu used\n",
grand_totals.totalspace, grand_totals.nblocks,
grand_totals.freespace, grand_totals.freechunks,
grand_totals.totalspace - grand_totals.freespace);
}
/*
* MemoryContextStatsInternal
* One recursion level for MemoryContextStats
*
* Print this context if print is true, but in any case accumulate counts into
* *totals (if given).
*/
static void
MemoryContextStatsInternal(MemoryContext context, int level,
bool print, int max_children,
MemoryContextCounters *totals)
{
MemoryContextCounters local_totals;
MemoryContext child;
int ichild;
AssertArg(MemoryContextIsValid(context));
/* Examine the context itself */
context->methods->stats(context,
print ? MemoryContextStatsPrint : NULL,
(void *) &level,
totals);
/*
* Examine children. If there are more than max_children of them, we do
* not print the rest explicitly, but just summarize them.
*/
memset(&local_totals, 0, sizeof(local_totals));
for (child = context->firstchild, ichild = 0;
child != NULL;
child = child->nextchild, ichild++)
{
if (ichild < max_children)
MemoryContextStatsInternal(child, level + 1,
print, max_children,
totals);
else
MemoryContextStatsInternal(child, level + 1,
false, max_children,
&local_totals);
}
/* Deal with excess children */
if (ichild > max_children)
{
if (print)
{
int i;
for (i = 0; i <= level; i++)
fprintf(stderr, " ");
fprintf(stderr,
"%d more child contexts containing %zu total in %zd blocks; %zu free (%zd chunks); %zu used\n",
ichild - max_children,
local_totals.totalspace,
local_totals.nblocks,
local_totals.freespace,
local_totals.freechunks,
local_totals.totalspace - local_totals.freespace);
}
if (totals)
{
totals->nblocks += local_totals.nblocks;
totals->freechunks += local_totals.freechunks;
totals->totalspace += local_totals.totalspace;
totals->freespace += local_totals.freespace;
}
}
}
/*
* MemoryContextStatsPrint
* Print callback used by MemoryContextStatsInternal
*
* For now, the passthru pointer just points to "int level"; later we might
* make that more complicated.
*/
static void
MemoryContextStatsPrint(MemoryContext context, void *passthru,
const char *stats_string)
{
int level = *(int *) passthru;
const char *name = context->name;
const char *ident = context->ident;
int i;
/*
* It seems preferable to label dynahash contexts with just the hash table
* name. Those are already unique enough, so the "dynahash" part isn't
* very helpful, and this way is more consistent with pre-v11 practice.
*/
if (ident && strcmp(name, "dynahash") == 0)
{
name = ident;
ident = NULL;
}
for (i = 0; i < level; i++)
fprintf(stderr, " ");
fprintf(stderr, "%s: %s", name, stats_string);
if (ident)
{
/*
* Some contexts may have very long identifiers (e.g., SQL queries).
* Arbitrarily truncate at 100 bytes, but be careful not to break
* multibyte characters. Also, replace ASCII control characters, such
* as newlines, with spaces.
*/
int idlen = strlen(ident);
bool truncated = false;
if (idlen > 100)
{
idlen = pg_mbcliplen(ident, idlen, 100);
truncated = true;
}
fprintf(stderr, ": ");
while (idlen-- > 0)
{
unsigned char c = *ident++;
if (c < ' ')
c = ' ';
fputc(c, stderr);
}
if (truncated)
fprintf(stderr, "...");
}
fputc('\n', stderr);
}
/*
* MemoryContextCheck
* Check all chunks in the named context.
*
* This is just a debugging utility, so it's not fancy.
*/
#ifdef MEMORY_CONTEXT_CHECKING
void
MemoryContextCheck(MemoryContext context)
{
MemoryContext child;
AssertArg(MemoryContextIsValid(context));
context->methods->check(context);
for (child = context->firstchild; child != NULL; child = child->nextchild)
MemoryContextCheck(child);
}
#endif
/*
* MemoryContextContains
* Detect whether an allocated chunk of memory belongs to a given
* context or not.
*
* Caution: this test is reliable as long as 'pointer' does point to
* a chunk of memory allocated from *some* context. If 'pointer' points
* at memory obtained in some other way, there is a small chance of a
* false-positive result, since the bits right before it might look like
* a valid chunk header by chance.
*/
bool
MemoryContextContains(MemoryContext context, void *pointer)
{
MemoryContext ptr_context;
/*
* In GPDB, pointer is not guaranteed to always be palloc aligned. Due to
* our use of MemTuples, the pointer may instead point into the palloc'd
* region to an attr offset. Therefore we cannot assume the MemoryContext
* from which the pointer was palloc'd exists in the bytes immediately in
* front of the pointer.
*
* Instead use MemoryContextContainsGenericAllocation() which correctly
* handles the above scenario.
*/
Assert(false);
/*
* NB: Can't use GetMemoryChunkContext() here - that performs assertions
* that aren't acceptable here since we might be passed memory not
* allocated by any memory context.
*
* Try to detect bogus pointers handed to us, poorly though we can.
* Presumably, a pointer that isn't MAXALIGNED isn't pointing at an
* allocated chunk.
*/
if (pointer == NULL || pointer != (void *) MAXALIGN(pointer))
return false;
/*
* OK, it's probably safe to look at the context.
*/
ptr_context = *(MemoryContext *) (((char *) pointer) - sizeof(void *));
return ptr_context == context;
}
/*
* MemoryContextContainsGenericAllocation
*
* Detects whether a generic (may or may not be allocated by palloc) chunk of
* memory belongs to a given context or not. Note, the "generic" means it will
* be ready to handle chunks not allocated using palloc, not at the start of an
* allocated region, and not necessarily aligned.
*
* Currently only supports AllocSet, will error out if called on any other type
* of MemoryContext (AllocSlab, ALlocGenerate, custom)
*
* Note for new callers: This will iterate through the linked list of blocks in the
* context provided; at present there are no functions calling it which would
* be expected to have more than 1 block allocated (or possibly a handful
* of blocks, if there are multiple large aggregate/window functions run
* simultaneously in the same query). If there were some reason why a new
* caller might pass a context with a large number of blocks (hundreds,
* thousands?) and needs to call this frequently, checking for potential
* performance implications before proceeding is recommended.
*/
bool
MemoryContextContainsGenericAllocation(MemoryContext context, void *pointer)
{
if (context->type != T_AllocSetContext)
MemoryContextError(ERRCODE_INTERNAL_ERROR,
context, CDB_MCXT_WHERE(context),
"MemoryContextContainsGenericAllocation is not available for type %u",
context->type);
return AllocSetContains(context, pointer);
}
/*--------------------
* MemoryContextCreate
* Context-type-independent part of context creation.
*
* This is only intended to be called by context-type-specific
* context creation routines, not by the unwashed masses.
*
* The memory context creation procedure goes like this:
* 1. Context-type-specific routine makes some initial space allocation,
* including enough space for the context header. If it fails,
* it can ereport() with no damage done.
* 2. Context-type-specific routine sets up all type-specific fields of
* the header (those beyond MemoryContextData proper), as well as any
* other management fields it needs to have a fully valid context.
* Usually, failure in this step is impossible, but if it's possible
* the initial space allocation should be freed before ereport'ing.
* 3. Context-type-specific routine calls MemoryContextCreate() to fill in
* the generic header fields and link the context into the context tree.
* 4. We return to the context-type-specific routine, which finishes
* up type-specific initialization. This routine can now do things
* that might fail (like allocate more memory), so long as it's
* sure the node is left in a state that delete will handle.
*
* node: the as-yet-uninitialized common part of the context header node.
* tag: NodeTag code identifying the memory context type.
* methods: context-type-specific methods (usually statically allocated).
* parent: parent context, or NULL if this will be a top-level context.
* name: name of context (must be statically allocated).
*
* Context routines generally assume that MemoryContextCreate can't fail,
* so this can contain Assert but not elog/ereport.
*/
void
MemoryContextCreate(MemoryContext node,
NodeTag tag,
const MemoryContextMethods *methods,
MemoryContext parent,
const char *name)
{
// GPDB_94_MERGE_FIXME: same as AssertNotInCriticalSection
#if 0
/* Creating new memory contexts is not allowed in a critical section */
Assert(CritSectionCount == 0);
#endif
/* Initialize all standard fields of memory context header */
node->type = tag;
node->isReset = true;
node->methods = methods;
node->parent = parent;
node->firstchild = NULL;
node->mem_allocated = 0;
node->prevchild = NULL;
node->name = name;
node->ident = NULL;
node->reset_cbs = NULL;
/* OK to link node into context tree */
if (parent)
{
node->nextchild = parent->firstchild;
if (parent->firstchild != NULL)
parent->firstchild->prevchild = node;
parent->firstchild = node;
/* inherit allowInCritSection flag from parent */
node->allowInCritSection = parent->allowInCritSection;
}
else
{
node->nextchild = NULL;
node->allowInCritSection = false;
}
VALGRIND_CREATE_MEMPOOL(node, 0, false);
}
/*
* MemoryContextAlloc
* Allocate space within the specified context.
*
* This could be turned into a macro, but we'd have to import
* nodes/memnodes.h into postgres.h which seems a bad idea.
*/
void *
MemoryContextAlloc(MemoryContext context, Size size)
{
void *ret;
AssertArg(MemoryContextIsValid(context));
AssertNotInCriticalSection(context);
#ifdef CDB_PALLOC_CALLER_ID
context->callerFile = sfile;
context->callerLine = sline;
#endif
if (!AllocSizeIsValid(size))
MemoryContextError(ERRCODE_INTERNAL_ERROR,
context, CDB_MCXT_WHERE(context),
"invalid memory alloc request size %lu",
(unsigned long)size);
context->isReset = false;
ret = context->methods->alloc(context, size);
if (unlikely(ret == NULL))
{
MemoryContextStats(TopMemoryContext);
/*
* Here, and elsewhere in this module, we show the target context's
* "name" but not its "ident" (if any) in user-visible error messages.
* The "ident" string might contain security-sensitive data, such as
* values in SQL commands.
*/
ereport(ERROR,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("out of memory"),
errdetail("Failed on request of size %zu in memory context \"%s\".",
size, context->name)));
}
VALGRIND_MEMPOOL_ALLOC(context, ret, size);
return ret;
}
/*
* MemoryContextAllocZero
* Like MemoryContextAlloc, but clears allocated memory
*
* We could just call MemoryContextAlloc then clear the memory, but this
* is a very common combination, so we provide the combined operation.
*/
void *
MemoryContextAllocZero(MemoryContext context, Size size)
{
void *ret;
AssertArg(MemoryContextIsValid(context));
AssertNotInCriticalSection(context);
#ifdef CDB_PALLOC_CALLER_ID
context->callerFile = sfile;
context->callerLine = sline;
#endif
if (!AllocSizeIsValid(size))
MemoryContextError(ERRCODE_INTERNAL_ERROR,
context, CDB_MCXT_WHERE(context),
"invalid memory alloc request size %lu",
(unsigned long)size);
context->isReset = false;
ret = context->methods->alloc(context, size);
if (unlikely(ret == NULL))
{
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, context->name)));
}
VALGRIND_MEMPOOL_ALLOC(context, ret, size);
MemSetAligned(ret, 0, size);
return ret;
}
/*
* MemoryContextAllocZeroAligned
* MemoryContextAllocZero where length is suitable for MemSetLoop
*
* This might seem overly specialized, but it's not because newNode()
* is so often called with compile-time-constant sizes.
*/
void *
MemoryContextAllocZeroAligned(MemoryContext context, Size size)
{
void *ret;
AssertArg(MemoryContextIsValid(context));
AssertNotInCriticalSection(context);
#ifdef CDB_PALLOC_CALLER_ID
context->callerFile = sfile;
context->callerLine = sline;
#endif
if (!AllocSizeIsValid(size))
MemoryContextError(ERRCODE_INTERNAL_ERROR,
context, CDB_MCXT_WHERE(context),
"invalid memory alloc request size %lu",
(unsigned long)size);
context->isReset = false;
ret = context->methods->alloc(context, size);
if (unlikely(ret == NULL))
{
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, context->name)));
}
VALGRIND_MEMPOOL_ALLOC(context, ret, size);
MemSetLoop(ret, 0, size);
return ret;
}
/*
* MemoryContextAllocExtended
* Allocate space within the specified context using the given flags.
*/
void *
MemoryContextAllocExtended(MemoryContext context, Size size, int flags)
{
void *ret;
AssertArg(MemoryContextIsValid(context));
AssertNotInCriticalSection(context);
if (((flags & MCXT_ALLOC_HUGE) != 0 && !AllocHugeSizeIsValid(size)) ||
((flags & MCXT_ALLOC_HUGE) == 0 && !AllocSizeIsValid(size)))
elog(ERROR, "invalid memory alloc request size %zu", size);
context->isReset = false;
ret = context->methods->alloc(context, size);
if (unlikely(ret == NULL))
{
if ((flags & MCXT_ALLOC_NO_OOM) == 0)
{
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, context->name)));
}
return NULL;
}
VALGRIND_MEMPOOL_ALLOC(context, ret, size);
if ((flags & MCXT_ALLOC_ZERO) != 0)
MemSetAligned(ret, 0, size);
return ret;
}
void *
palloc(Size size)
{
/* duplicates MemoryContextAlloc to avoid increased overhead */
void *ret;
MemoryContext context = CurrentMemoryContext;
AssertArg(MemoryContextIsValid(context));
AssertNotInCriticalSection(context);
if (!AllocSizeIsValid(size))
elog(ERROR, "invalid memory alloc request size %zu", size);
context->isReset = false;
ret = context->methods->alloc(context, size);
if (unlikely(ret == NULL))
{
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, context->name)));
}
VALGRIND_MEMPOOL_ALLOC(context, ret, size);
return ret;
}
void *
palloc0(Size size)
{
/* duplicates MemoryContextAllocZero to avoid increased overhead */
void *ret;
MemoryContext context = CurrentMemoryContext;
AssertArg(MemoryContextIsValid(context));
AssertNotInCriticalSection(context);
if (!AllocSizeIsValid(size))
elog(ERROR, "invalid memory alloc request size %zu", size);
context->isReset = false;
ret = context->methods->alloc(context, size);
if (unlikely(ret == NULL))
{
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, context->name)));
}
VALGRIND_MEMPOOL_ALLOC(context, ret, size);
MemSetAligned(ret, 0, size);
return ret;
}
void *
palloc_extended(Size size, int flags)
{
/* duplicates MemoryContextAllocExtended to avoid increased overhead */
void *ret;
MemoryContext context = CurrentMemoryContext;
AssertArg(MemoryContextIsValid(context));
AssertNotInCriticalSection(context);
if (((flags & MCXT_ALLOC_HUGE) != 0 && !AllocHugeSizeIsValid(size)) ||
((flags & MCXT_ALLOC_HUGE) == 0 && !AllocSizeIsValid(size)))
elog(ERROR, "invalid memory alloc request size %zu", size);
context->isReset = false;
ret = context->methods->alloc(context, size);
if (unlikely(ret == NULL))
{
if ((flags & MCXT_ALLOC_NO_OOM) == 0)
{
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, context->name)));
}
return NULL;
}
VALGRIND_MEMPOOL_ALLOC(context, ret, size);
if ((flags & MCXT_ALLOC_ZERO) != 0)
MemSetAligned(ret, 0, size);
return ret;
}
/*
* pfree
* Release an allocated chunk.
*/
void
pfree(void *pointer)
{
MemoryContext context = GetMemoryChunkContext(pointer);
context->methods->free_p(context, pointer);
VALGRIND_MEMPOOL_FREE(context, pointer);
}
/*
* repalloc
* Adjust the size of a previously allocated chunk.
*/
void *
repalloc(void *pointer, Size size)
{
MemoryContext context = GetMemoryChunkContext(pointer);
void *ret;
if (!AllocSizeIsValid(size))
elog(ERROR, "invalid memory alloc request size %zu", size);
AssertNotInCriticalSection(context);
/* isReset must be false already */
Assert(!context->isReset);
ret = context->methods->realloc(context, pointer, size);
if (unlikely(ret == NULL))
{
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, context->name)));
}
VALGRIND_MEMPOOL_CHANGE(context, pointer, ret, size);
return ret;
}
/*
* MemoryContextAllocHuge
* Allocate (possibly-expansive) space within the specified context.
*
* See considerations in comment at MaxAllocHugeSize.
*/
void *
MemoryContextAllocHuge(MemoryContext context, Size size)
{
void *ret;
AssertArg(MemoryContextIsValid(context));
AssertNotInCriticalSection(context);
if (!AllocHugeSizeIsValid(size))
elog(ERROR, "invalid memory alloc request size %zu", size);
context->isReset = false;
ret = context->methods->alloc(context, size);
if (unlikely(ret == NULL))
{
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, context->name)));
}
VALGRIND_MEMPOOL_ALLOC(context, ret, size);
return ret;
}
/*
* repalloc_huge
* Adjust the size of a previously allocated chunk, permitting a large
* value. The previous allocation need not have been "huge".
*/
void *
repalloc_huge(void *pointer, Size size)
{
MemoryContext context = GetMemoryChunkContext(pointer);
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 = context->methods->realloc(context, pointer, size);
if (unlikely(ret == NULL))
{
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, context->name)));
}
VALGRIND_MEMPOOL_CHANGE(context, pointer, ret, size);
return ret;
}
/*
* MemoryContextStrdup
* Like strdup(), but allocate from the specified context
*/
char *
MemoryContextStrdup(MemoryContext context, const char *string)
{
char *nstr;
Size len = strlen(string) + 1;
nstr = (char *) MemoryContextAlloc(context, len);
memcpy(nstr, string, len);
return nstr;
}
char *
pstrdup(const char *in)
{
return MemoryContextStrdup(CurrentMemoryContext, in);
}
/*
* pnstrdup
* Like pstrdup(), but append null byte to a
* not-necessarily-null-terminated input string.
*/
char *
pnstrdup(const char *in, Size len)
{
char *out;
len = strnlen(in, len);
out = palloc(len + 1);
memcpy(out, in, len);
out[len] = '\0';
return out;
}
/*
* Make copy of string with all trailing newline characters removed.
*/
char *
pchomp(const char *in)
{
size_t n;
n = strlen(in);
while (n > 0 && in[n - 1] == '\n')
n--;
return pnstrdup(in, n);
}
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