sys/memory/mtr.c

/*
     Interface to malloc() and free(). This code allows for logging of memory usage and some error checking
*/
#include <petsc/private/petscimpl.h> /*I "petscsys.h" I*/
#include <petscviewer.h>
#if defined(PETSC_HAVE_MALLOC_H)
  #include <malloc.h>
#endif

/*
     These are defined in mal.c and ensure that malloced space is PetscScalar aligned
*/
PETSC_EXTERN PetscErrorCode PetscMallocAlign(size_t, PetscBool, int, const char[], const char[], void **);
PETSC_EXTERN PetscErrorCode PetscFreeAlign(void *, int, const char[], const char[]);
PETSC_EXTERN PetscErrorCode PetscReallocAlign(size_t, int, const char[], const char[], void **);

#define CLASSID_VALUE ((PetscClassId)0xf0e0d0c9)
#define ALREADY_FREED ((PetscClassId)0x0f0e0d9c)

/*  this is the header put at the beginning of each malloc() using for tracking allocated space and checking of allocated space heap */
typedef struct _trSPACE {
  size_t       size, rsize; /* Aligned size and requested size */
  int          id;
  int          lineno;
  const char  *filename;
  const char  *functionname;
  PetscClassId classid;
#if defined(PETSC_USE_DEBUG) && !defined(PETSC_HAVE_THREADSAFETY)
  PetscStack stack;
#endif
  struct _trSPACE *next, *prev;
} TRSPACE;

/* HEADER_BYTES is the number of bytes in a PetscMalloc() header.
   It is sizeof(trSPACE) padded to be a multiple of PETSC_MEMALIGN.
*/
#define HEADER_BYTES ((sizeof(TRSPACE) + (PETSC_MEMALIGN - 1)) & ~(PETSC_MEMALIGN - 1))

/* This union is used to insure that the block passed to the user retains
   a minimum alignment of PETSC_MEMALIGN.
*/
typedef union
{
  TRSPACE sp;
  char    v[HEADER_BYTES];
} TrSPACE;

#define MAXTRMAXMEMS 50
static size_t    TRallocated           = 0;
static int       TRfrags               = 0;
static TRSPACE  *TRhead                = NULL;
static int       TRid                  = 0;
static PetscBool TRdebugLevel          = PETSC_FALSE;
static PetscBool TRdebugIinitializenan = PETSC_FALSE;
static PetscBool TRrequestedSize       = PETSC_FALSE;
static size_t    TRMaxMem              = 0;
static int       NumTRMaxMems          = 0;
static size_t    TRMaxMems[MAXTRMAXMEMS];
static int       TRMaxMemsEvents[MAXTRMAXMEMS];
/*
      Arrays to log information on mallocs for PetscMallocView()
*/
static int          PetscLogMallocMax       = 10000;
static int          PetscLogMalloc          = -1;
static size_t       PetscLogMallocThreshold = 0;
static size_t      *PetscLogMallocLength;
static const char **PetscLogMallocFile, **PetscLogMallocFunction;
static int          PetscLogMallocTrace          = -1;
static size_t       PetscLogMallocTraceThreshold = 0;
static PetscViewer  PetscLogMallocTraceViewer    = NULL;

/*@C
   PetscMallocValidate - Test the memory for corruption.  This can be called at any time between `PetscInitialize()` and `PetscFinalize()`

   Input Parameters:
+  line - line number where call originated.
.  function - name of function calling
-  file - file where function is

   Return value:
   The number of errors detected.

   Options Database Keys:.
+  -malloc_test - turns this feature on when PETSc was not configured with --with-debugging=0
-  -malloc_debug - turns this feature on anytime

   Output Effect:
   Error messages are written to stdout.

   Level: advanced

   Notes:
    This is only run if `PetscMallocSetDebug()` has been called which is set by -malloc_test (if debugging is turned on) or -malloc_debug (any time)

    You should generally use `CHKMEMQ` as a short cut for calling this  routine.

    The Fortran calling sequence is simply `PetscMallocValidate(ierr)`

   No output is generated if there are no problems detected.

   Developers Note:
     Uses the flg TRdebugLevel (set as the first argument to `PetscMallocSetDebug()`) to determine if it should run

.seealso: `CHKMEMQ`
@*/
PetscErrorCode PetscMallocValidate(int line, const char function[], const char file[])
{
  TRSPACE      *head, *lasthead;
  char         *a;
  PetscClassId *nend;

  if (!TRdebugLevel) return PETSC_SUCCESS;
  head     = TRhead;
  lasthead = NULL;
  if (head && head->prev) {
    PetscCall((*PetscErrorPrintf)("PetscMallocValidate: error detected in %s() at %s:%d\n", function, file, line));
    PetscCall((*PetscErrorPrintf)("Root memory header %p has invalid back pointer %p\n", (void *)head, (void *)head->prev));
    return PETSC_ERR_MEMC;
  }
  while (head) {
    if (head->classid != CLASSID_VALUE) {
      PetscCall((*PetscErrorPrintf)("PetscMallocValidate: error detected in %s() at %s:%d\n", function, file, line));
      PetscCall((*PetscErrorPrintf)("Memory at address %p is corrupted\n", (void *)head));
      PetscCall((*PetscErrorPrintf)("Probably write before beginning of or past end of array\n"));
      if (lasthead) {
        a = (char *)(((TrSPACE *)head) + 1);
        PetscCall((*PetscErrorPrintf)("Last intact block [id=%d(%.0f)] at address %p allocated in %s() at %s:%d\n", lasthead->id, (PetscLogDouble)lasthead->size, a, lasthead->functionname, lasthead->filename, lasthead->lineno));
      }
      abort();
      return PETSC_ERR_MEMC;
    }
    a    = (char *)(((TrSPACE *)head) + 1);
    nend = (PetscClassId *)(a + head->size);
    if (*nend != CLASSID_VALUE) {
      PetscCall((*PetscErrorPrintf)("PetscMallocValidate: error detected in %s() at %s:%d\n", function, file, line));
      if (*nend == ALREADY_FREED) {
        PetscCall((*PetscErrorPrintf)("Memory [id=%d(%.0f)] at address %p already freed\n", head->id, (PetscLogDouble)head->size, a));
        return PETSC_ERR_MEMC;
      } else {
        PetscCall((*PetscErrorPrintf)("Memory [id=%d(%.0f)] at address %p is corrupted (probably write past end of array)\n", head->id, (PetscLogDouble)head->size, a));
        PetscCall((*PetscErrorPrintf)("Memory originally allocated in %s() at %s:%d\n", head->functionname, head->filename, head->lineno));
        return PETSC_ERR_MEMC;
      }
    }
    if (head->prev && head->prev != lasthead) {
      PetscCall((*PetscErrorPrintf)("PetscMallocValidate: error detected in %s() at %s:%d\n", function, file, line));
      PetscCall((*PetscErrorPrintf)("Backpointer %p is invalid, should be %p\n", (void *)head->prev, (void *)lasthead));
      PetscCall((*PetscErrorPrintf)("Previous memory originally allocated in %s() at %s:%d\n", lasthead->functionname, lasthead->filename, lasthead->lineno));
      PetscCall((*PetscErrorPrintf)("Memory originally allocated in %s() at %s:%d\n", head->functionname, head->filename, head->lineno));
      return PETSC_ERR_MEMC;
    }
    lasthead = head;
    head     = head->next;
  }
  return PETSC_SUCCESS;
}

/*
    PetscTrMallocDefault - Malloc with tracing.

    Input Parameters:
+   a   - number of bytes to allocate
.   lineno - line number where used.  Use __LINE__ for this
-   filename  - file name where used.  Use __FILE__ for this

    Returns:
    double aligned pointer to requested storage, or null if not  available.
 */
PetscErrorCode PetscTrMallocDefault(size_t a, PetscBool clear, int lineno, const char function[], const char filename[], void **result)
{
  TRSPACE *head;
  char    *inew;
  size_t   nsize;

  PetscFunctionBegin;
  /* Do not try to handle empty blocks */
  if (!a) {
    *result = NULL;
    PetscFunctionReturn(PETSC_SUCCESS);
  }

  PetscCall(PetscMallocValidate(lineno, function, filename));

  nsize = (a + (PETSC_MEMALIGN - 1)) & ~(PETSC_MEMALIGN - 1);
  PetscCall(PetscMallocAlign(nsize + sizeof(TrSPACE) + sizeof(PetscClassId), clear, lineno, function, filename, (void **)&inew));

  head = (TRSPACE *)inew;
  inew += sizeof(TrSPACE);

  if (TRhead) TRhead->prev = head;
  head->next   = TRhead;
  TRhead       = head;
  head->prev   = NULL;
  head->size   = nsize;
  head->rsize  = a;
  head->id     = TRid++;
  head->lineno = lineno;

  head->filename                  = filename;
  head->functionname              = function;
  head->classid                   = CLASSID_VALUE;
  *(PetscClassId *)(inew + nsize) = CLASSID_VALUE;

  TRallocated += TRrequestedSize ? head->rsize : head->size;
  if (TRallocated > TRMaxMem) TRMaxMem = TRallocated;
  if (PetscLogMemory) {
    PetscInt i;
    for (i = 0; i < NumTRMaxMems; i++) {
      if (TRallocated > TRMaxMems[i]) TRMaxMems[i] = TRallocated;
    }
  }
  TRfrags++;

#if defined(PETSC_USE_DEBUG) && !defined(PETSC_HAVE_THREADSAFETY)
  PetscCall(PetscStackCopy(&petscstack, &head->stack));
  /* fix the line number to where the malloc() was called, not the PetscFunctionBegin; */
  head->stack.line[head->stack.currentsize - 2] = lineno;
  #if defined(PETSC_USE_REAL_SINGLE) || defined(PETSC_USE_REAL_DOUBLE)
  if (!clear && TRdebugIinitializenan) {
    size_t     i, n = a / sizeof(PetscReal);
    PetscReal *s = (PetscReal *)inew;
      /* from https://www.doc.ic.ac.uk/~eedwards/compsys/float/nan.html */
    #if defined(PETSC_USE_REAL_SINGLE)
    int nas = 0x7F800002;
    #else
    PetscInt64 nas = 0x7FF0000000000002;
    #endif
    for (i = 0; i < n; i++) memcpy(s + i, &nas, sizeof(PetscReal));
  }
  #endif
#endif

  /*
         Allow logging of all mallocs made.
         TODO: Currently this memory is never freed, it should be freed during PetscFinalize()
  */
  if (PetscLogMalloc > -1 && PetscLogMalloc < PetscLogMallocMax && a >= PetscLogMallocThreshold) {
    if (!PetscLogMalloc) {
      PetscLogMallocLength = (size_t *)malloc(PetscLogMallocMax * sizeof(size_t));
      PetscCheck(PetscLogMallocLength, PETSC_COMM_SELF, PETSC_ERR_MEM, " ");

      PetscLogMallocFile = (const char **)malloc(PetscLogMallocMax * sizeof(char *));
      PetscCheck(PetscLogMallocFile, PETSC_COMM_SELF, PETSC_ERR_MEM, " ");

      PetscLogMallocFunction = (const char **)malloc(PetscLogMallocMax * sizeof(char *));
      PetscCheck(PetscLogMallocFunction, PETSC_COMM_SELF, PETSC_ERR_MEM, " ");
    }
    PetscLogMallocLength[PetscLogMalloc]     = nsize;
    PetscLogMallocFile[PetscLogMalloc]       = filename;
    PetscLogMallocFunction[PetscLogMalloc++] = function;
  }
  if (PetscLogMallocTrace > -1 && a >= PetscLogMallocTraceThreshold) PetscCall(PetscViewerASCIIPrintf(PetscLogMallocTraceViewer, "Alloc %zu %s:%d (%s)\n", a, filename ? filename : "null", lineno, function ? function : "null"));
  *result = (void *)inew;
  PetscFunctionReturn(PETSC_SUCCESS);
}

/*
   PetscTrFreeDefault - Free with tracing.

   Input Parameters:
.   a    - pointer to a block allocated with PetscTrMalloc
.   lineno - line number where used.  Use __LINE__ for this
.   filename  - file name where used.  Use __FILE__ for this
 */
PetscErrorCode PetscTrFreeDefault(void *aa, int lineno, const char function[], const char filename[])
{
  char         *a = (char *)aa;
  TRSPACE      *head;
  char         *ahead;
  size_t        asize;
  PetscClassId *nend;

  PetscFunctionBegin;
  /* Do not try to handle empty blocks */
  if (!a) PetscFunctionReturn(PETSC_SUCCESS);

  PetscCall(PetscMallocValidate(lineno, function, filename));

  ahead = a;
  a     = a - sizeof(TrSPACE);
  head  = (TRSPACE *)a;

  if (head->classid != CLASSID_VALUE) {
    PetscCall((*PetscErrorPrintf)("PetscTrFreeDefault() called from %s() at %s:%d\n", function, filename, lineno));
    PetscCall((*PetscErrorPrintf)("Block at address %p is corrupted; cannot free;\nmay be block not allocated with PetscMalloc()\n", a));
    SETERRQ(PETSC_COMM_SELF, PETSC_ERR_MEMC, "Bad location or corrupted memory");
  }
  nend = (PetscClassId *)(ahead + head->size);
  if (*nend != CLASSID_VALUE) {
    if (*nend == ALREADY_FREED) {
      PetscCall((*PetscErrorPrintf)("PetscTrFreeDefault() called from %s() at %s:%d\n", function, filename, lineno));
      PetscCall((*PetscErrorPrintf)("Block [id=%d(%.0f)] at address %p was already freed\n", head->id, (PetscLogDouble)head->size, a + sizeof(TrSPACE)));
      if (head->lineno > 0 && head->lineno < 50000 /* sanity check */) {
        PetscCall((*PetscErrorPrintf)("Block freed in %s() at %s:%d\n", head->functionname, head->filename, head->lineno));
      } else {
        PetscCall((*PetscErrorPrintf)("Block allocated in %s() at %s:%d\n", head->functionname, head->filename, -head->lineno));
      }
      SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Memory already freed");
    } else {
      /* Damaged tail */
      PetscCall((*PetscErrorPrintf)("PetscTrFreeDefault() called from %s() at %s:%d\n", function, filename, lineno));
      PetscCall((*PetscErrorPrintf)("Block [id=%d(%.0f)] at address %p is corrupted (probably write past end of array)\n", head->id, (PetscLogDouble)head->size, a));
      PetscCall((*PetscErrorPrintf)("Block allocated in %s() at %s:%d\n", head->functionname, head->filename, head->lineno));
      SETERRQ(PETSC_COMM_SELF, PETSC_ERR_MEMC, "Corrupted memory");
    }
  }
  if (PetscLogMallocTrace > -1 && head->rsize >= PetscLogMallocTraceThreshold) {
    PetscCall(PetscViewerASCIIPrintf(PetscLogMallocTraceViewer, "Free  %zu %s:%d (%s)\n", head->rsize, filename ? filename : "null", lineno, function ? function : "null"));
  }
  /* Mark the location freed */
  *nend = ALREADY_FREED;
  /* Save location where freed.  If we suspect the line number, mark as  allocated location */
  if (lineno > 0 && lineno < 50000) {
    head->lineno       = lineno;
    head->filename     = filename;
    head->functionname = function;
  } else {
    head->lineno = -head->lineno;
  }
  asize = TRrequestedSize ? head->rsize : head->size;
  PetscCheck(TRallocated >= asize, PETSC_COMM_SELF, PETSC_ERR_MEMC, "TRallocate is smaller than memory just freed");
  TRallocated -= asize;
  TRfrags--;
  if (head->prev) head->prev->next = head->next;
  else TRhead = head->next;

  if (head->next) head->next->prev = head->prev;
  PetscCall(PetscFreeAlign(a, lineno, function, filename));
  PetscFunctionReturn(PETSC_SUCCESS);
}

/*
  PetscTrReallocDefault - Realloc with tracing.

  Input Parameters:
+ len      - number of bytes to allocate
. lineno   - line number where used.  Use __LINE__ for this
. filename - file name where used.  Use __FILE__ for this
- result - original memory

  Output Parameter:
. result - double aligned pointer to requested storage, or null if not available.

  Level: developer

.seealso: `PetscTrMallocDefault()`, `PetscTrFreeDefault()`
*/
PetscErrorCode PetscTrReallocDefault(size_t len, int lineno, const char function[], const char filename[], void **result)
{
  char         *a = (char *)*result;
  TRSPACE      *head;
  char         *ahead, *inew;
  PetscClassId *nend;
  size_t        nsize;

  PetscFunctionBegin;
  /* Realloc requests zero space so just free the current space */
  if (!len) {
    PetscCall(PetscTrFreeDefault(*result, lineno, function, filename));
    *result = NULL;
    PetscFunctionReturn(PETSC_SUCCESS);
  }
  /* If the original space was NULL just use the regular malloc() */
  if (!*result) {
    PetscCall(PetscTrMallocDefault(len, PETSC_FALSE, lineno, function, filename, result));
    PetscFunctionReturn(PETSC_SUCCESS);
  }

  PetscCall(PetscMallocValidate(lineno, function, filename));

  ahead = a;
  a     = a - sizeof(TrSPACE);
  head  = (TRSPACE *)a;
  inew  = a;

  if (head->classid != CLASSID_VALUE) {
    PetscCall((*PetscErrorPrintf)("PetscTrReallocDefault() called from %s() at %s:%d\n", function, filename, lineno));
    PetscCall((*PetscErrorPrintf)("Block at address %p is corrupted; cannot free;\nmay be block not allocated with PetscMalloc()\n", a));
    SETERRQ(PETSC_COMM_SELF, PETSC_ERR_MEMC, "Bad location or corrupted memory");
  }
  nend = (PetscClassId *)(ahead + head->size);
  if (*nend != CLASSID_VALUE) {
    if (*nend == ALREADY_FREED) {
      PetscCall((*PetscErrorPrintf)("PetscTrReallocDefault() called from %s() at %s:%d\n", function, filename, lineno));
      PetscCall((*PetscErrorPrintf)("Block [id=%d(%.0f)] at address %p was already freed\n", head->id, (PetscLogDouble)head->size, a + sizeof(TrSPACE)));
      if (head->lineno > 0 && head->lineno < 50000 /* sanity check */) {
        PetscCall((*PetscErrorPrintf)("Block freed in %s() at %s:%d\n", head->functionname, head->filename, head->lineno));
      } else {
        PetscCall((*PetscErrorPrintf)("Block allocated in %s() at %s:%d\n", head->functionname, head->filename, -head->lineno));
      }
      SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Memory already freed");
    } else {
      /* Damaged tail */
      PetscCall((*PetscErrorPrintf)("PetscTrReallocDefault() called from %s() at %s:%d\n", function, filename, lineno));
      PetscCall((*PetscErrorPrintf)("Block [id=%d(%.0f)] at address %p is corrupted (probably write past end of array)\n", head->id, (PetscLogDouble)head->size, a));
      PetscCall((*PetscErrorPrintf)("Block allocated in %s() at %s:%d\n", head->functionname, head->filename, head->lineno));
      SETERRQ(PETSC_COMM_SELF, PETSC_ERR_MEMC, "Corrupted memory");
    }
  }

  /* remove original reference to the memory allocated from the PETSc debugging heap */
  TRallocated -= TRrequestedSize ? head->rsize : head->size;
  TRfrags--;
  if (head->prev) head->prev->next = head->next;
  else TRhead = head->next;
  if (head->next) head->next->prev = head->prev;

  nsize = (len + (PETSC_MEMALIGN - 1)) & ~(PETSC_MEMALIGN - 1);
  PetscCall(PetscReallocAlign(nsize + sizeof(TrSPACE) + sizeof(PetscClassId), lineno, function, filename, (void **)&inew));

  head = (TRSPACE *)inew;
  inew += sizeof(TrSPACE);

  if (TRhead) TRhead->prev = head;
  head->next   = TRhead;
  TRhead       = head;
  head->prev   = NULL;
  head->size   = nsize;
  head->rsize  = len;
  head->id     = TRid++;
  head->lineno = lineno;

  head->filename                  = filename;
  head->functionname              = function;
  head->classid                   = CLASSID_VALUE;
  *(PetscClassId *)(inew + nsize) = CLASSID_VALUE;

  TRallocated += TRrequestedSize ? head->rsize : head->size;
  if (TRallocated > TRMaxMem) TRMaxMem = TRallocated;
  if (PetscLogMemory) {
    PetscInt i;
    for (i = 0; i < NumTRMaxMems; i++) {
      if (TRallocated > TRMaxMems[i]) TRMaxMems[i] = TRallocated;
    }
  }
  TRfrags++;

#if defined(PETSC_USE_DEBUG) && !defined(PETSC_HAVE_THREADSAFETY)
  PetscCall(PetscStackCopy(&petscstack, &head->stack));
  /* fix the line number to where the malloc() was called, not the PetscFunctionBegin; */
  head->stack.line[head->stack.currentsize - 2] = lineno;
#endif

  /*
         Allow logging of all mallocs made. This adds a new entry to the list of allocated memory
         and does not remove the previous entry to the list hence this memory is "double counted" in PetscMallocView()
  */
  if (PetscLogMalloc > -1 && PetscLogMalloc < PetscLogMallocMax && len >= PetscLogMallocThreshold) {
    if (!PetscLogMalloc) {
      PetscLogMallocLength = (size_t *)malloc(PetscLogMallocMax * sizeof(size_t));
      PetscCheck(PetscLogMallocLength, PETSC_COMM_SELF, PETSC_ERR_MEM, " ");

      PetscLogMallocFile = (const char **)malloc(PetscLogMallocMax * sizeof(char *));
      PetscCheck(PetscLogMallocFile, PETSC_COMM_SELF, PETSC_ERR_MEM, " ");

      PetscLogMallocFunction = (const char **)malloc(PetscLogMallocMax * sizeof(char *));
      PetscCheck(PetscLogMallocFunction, PETSC_COMM_SELF, PETSC_ERR_MEM, " ");
    }
    PetscLogMallocLength[PetscLogMalloc]     = nsize;
    PetscLogMallocFile[PetscLogMalloc]       = filename;
    PetscLogMallocFunction[PetscLogMalloc++] = function;
  }
  *result = (void *)inew;
  PetscFunctionReturn(PETSC_SUCCESS);
}

/*@C
    PetscMemoryView - Shows the amount of memory currently being used in a communicator.

    Collective

    Input Parameters:
+    viewer - the viewer that defines the communicator
-    message - string printed before values

    Options Database Keys:
+    -malloc_debug - have PETSc track how much memory it has allocated
.    -log_view_memory - print memory usage per event
-    -memory_view - during PetscFinalize() have this routine called

    Level: intermediate

.seealso: `PetscMallocDump()`, `PetscMemoryGetCurrentUsage()`, `PetscMemorySetGetMaximumUsage()`, `PetscMallocView()`
 @*/
PetscErrorCode PetscMemoryView(PetscViewer viewer, const char message[])
{
  PetscLogDouble allocated, allocatedmax, resident, residentmax, gallocated, gallocatedmax, gresident, gresidentmax, maxgallocated, maxgallocatedmax, maxgresident, maxgresidentmax;
  PetscLogDouble mingallocated, mingallocatedmax, mingresident, mingresidentmax;
  MPI_Comm       comm;

  PetscFunctionBegin;
  if (!viewer) viewer = PETSC_VIEWER_STDOUT_WORLD;
  PetscCall(PetscMallocGetCurrentUsage(&allocated));
  PetscCall(PetscMallocGetMaximumUsage(&allocatedmax));
  PetscCall(PetscMemoryGetCurrentUsage(&resident));
  PetscCall(PetscMemoryGetMaximumUsage(&residentmax));
  if (residentmax > 0) residentmax = PetscMax(resident, residentmax);
  PetscCall(PetscObjectGetComm((PetscObject)viewer, &comm));
  PetscCall(PetscViewerASCIIPrintf(viewer, "%s", message));
  if (resident && residentmax && allocated) {
    PetscCallMPI(MPI_Reduce(&residentmax, &gresidentmax, 1, MPIU_PETSCLOGDOUBLE, MPI_SUM, 0, comm));
    PetscCallMPI(MPI_Reduce(&residentmax, &maxgresidentmax, 1, MPIU_PETSCLOGDOUBLE, MPI_MAX, 0, comm));
    PetscCallMPI(MPI_Reduce(&residentmax, &mingresidentmax, 1, MPIU_PETSCLOGDOUBLE, MPI_MIN, 0, comm));
    PetscCall(PetscViewerASCIIPrintf(viewer, "Maximum (over computational time) process memory:        total %5.4e max %5.4e min %5.4e\n", gresidentmax, maxgresidentmax, mingresidentmax));
    PetscCallMPI(MPI_Reduce(&resident, &gresident, 1, MPIU_PETSCLOGDOUBLE, MPI_SUM, 0, comm));
    PetscCallMPI(MPI_Reduce(&resident, &maxgresident, 1, MPIU_PETSCLOGDOUBLE, MPI_MAX, 0, comm));
    PetscCallMPI(MPI_Reduce(&resident, &mingresident, 1, MPIU_PETSCLOGDOUBLE, MPI_MIN, 0, comm));
    PetscCall(PetscViewerASCIIPrintf(viewer, "Current process memory:                                  total %5.4e max %5.4e min %5.4e\n", gresident, maxgresident, mingresident));
    PetscCallMPI(MPI_Reduce(&allocatedmax, &gallocatedmax, 1, MPIU_PETSCLOGDOUBLE, MPI_SUM, 0, comm));
    PetscCallMPI(MPI_Reduce(&allocatedmax, &maxgallocatedmax, 1, MPIU_PETSCLOGDOUBLE, MPI_MAX, 0, comm));
    PetscCallMPI(MPI_Reduce(&allocatedmax, &mingallocatedmax, 1, MPIU_PETSCLOGDOUBLE, MPI_MIN, 0, comm));
    PetscCall(PetscViewerASCIIPrintf(viewer, "Maximum (over computational time) space PetscMalloc()ed: total %5.4e max %5.4e min %5.4e\n", gallocatedmax, maxgallocatedmax, mingallocatedmax));
    PetscCallMPI(MPI_Reduce(&allocated, &gallocated, 1, MPIU_PETSCLOGDOUBLE, MPI_SUM, 0, comm));
    PetscCallMPI(MPI_Reduce(&allocated, &maxgallocated, 1, MPIU_PETSCLOGDOUBLE, MPI_MAX, 0, comm));
    PetscCallMPI(MPI_Reduce(&allocated, &mingallocated, 1, MPIU_PETSCLOGDOUBLE, MPI_MIN, 0, comm));
    PetscCall(PetscViewerASCIIPrintf(viewer, "Current space PetscMalloc()ed:                           total %5.4e max %5.4e min %5.4e\n", gallocated, maxgallocated, mingallocated));
  } else if (resident && residentmax) {
    PetscCallMPI(MPI_Reduce(&residentmax, &gresidentmax, 1, MPIU_PETSCLOGDOUBLE, MPI_SUM, 0, comm));
    PetscCallMPI(MPI_Reduce(&residentmax, &maxgresidentmax, 1, MPIU_PETSCLOGDOUBLE, MPI_MAX, 0, comm));
    PetscCallMPI(MPI_Reduce(&residentmax, &mingresidentmax, 1, MPIU_PETSCLOGDOUBLE, MPI_MIN, 0, comm));
    PetscCall(PetscViewerASCIIPrintf(viewer, "Maximum (over computational time) process memory:        total %5.4e max %5.4e min %5.4e\n", gresidentmax, maxgresidentmax, mingresidentmax));
    PetscCallMPI(MPI_Reduce(&resident, &gresident, 1, MPIU_PETSCLOGDOUBLE, MPI_SUM, 0, comm));
    PetscCallMPI(MPI_Reduce(&resident, &maxgresident, 1, MPIU_PETSCLOGDOUBLE, MPI_MAX, 0, comm));
    PetscCallMPI(MPI_Reduce(&resident, &mingresident, 1, MPIU_PETSCLOGDOUBLE, MPI_MIN, 0, comm));
    PetscCall(PetscViewerASCIIPrintf(viewer, "Current process memory:                                  total %5.4e max %5.4e min %5.4e\n", gresident, maxgresident, mingresident));
  } else if (resident && allocated) {
    PetscCallMPI(MPI_Reduce(&resident, &gresident, 1, MPIU_PETSCLOGDOUBLE, MPI_SUM, 0, comm));
    PetscCallMPI(MPI_Reduce(&resident, &maxgresident, 1, MPIU_PETSCLOGDOUBLE, MPI_MAX, 0, comm));
    PetscCallMPI(MPI_Reduce(&resident, &mingresident, 1, MPIU_PETSCLOGDOUBLE, MPI_MIN, 0, comm));
    PetscCall(PetscViewerASCIIPrintf(viewer, "Current process memory:                                  total %5.4e max %5.4e min %5.4e\n", gresident, maxgresident, mingresident));
    PetscCallMPI(MPI_Reduce(&allocated, &gallocated, 1, MPIU_PETSCLOGDOUBLE, MPI_SUM, 0, comm));
    PetscCallMPI(MPI_Reduce(&allocated, &maxgallocated, 1, MPIU_PETSCLOGDOUBLE, MPI_MAX, 0, comm));
    PetscCallMPI(MPI_Reduce(&allocated, &mingallocated, 1, MPIU_PETSCLOGDOUBLE, MPI_MIN, 0, comm));
    PetscCall(PetscViewerASCIIPrintf(viewer, "Current space PetscMalloc()ed:                           total %5.4e max %5.4e min %5.4e\n", gallocated, maxgallocated, mingallocated));
    PetscCall(PetscViewerASCIIPrintf(viewer, "Run with -memory_view to get maximum memory usage\n"));
  } else if (allocated) {
    PetscCallMPI(MPI_Reduce(&allocated, &gallocated, 1, MPIU_PETSCLOGDOUBLE, MPI_SUM, 0, comm));
    PetscCallMPI(MPI_Reduce(&allocated, &maxgallocated, 1, MPIU_PETSCLOGDOUBLE, MPI_MAX, 0, comm));
    PetscCallMPI(MPI_Reduce(&allocated, &mingallocated, 1, MPIU_PETSCLOGDOUBLE, MPI_MIN, 0, comm));
    PetscCall(PetscViewerASCIIPrintf(viewer, "Current space PetscMalloc()ed:                           total %5.4e max %5.4e min %5.4e\n", gallocated, maxgallocated, mingallocated));
    PetscCall(PetscViewerASCIIPrintf(viewer, "Run with -memory_view to get maximum memory usage\n"));
    PetscCall(PetscViewerASCIIPrintf(viewer, "OS cannot compute process memory\n"));
  } else {
    PetscCall(PetscViewerASCIIPrintf(viewer, "Run with -malloc_debug to get statistics on PetscMalloc() calls\nOS cannot compute process memory\n"));
  }
  PetscCall(PetscViewerFlush(viewer));
  PetscFunctionReturn(PETSC_SUCCESS);
}

/*@
    PetscMallocGetCurrentUsage - gets the current amount of memory used that was allocated with `PetscMalloc()`

    Not Collective

    Output Parameters:
.   space - number of bytes currently allocated

    Level: intermediate

.seealso: `PetscMallocDump()`, `PetscMallocGetMaximumUsage()`, `PetscMemoryGetCurrentUsage()`,
          `PetscMemoryGetMaximumUsage()`
 @*/
PetscErrorCode PetscMallocGetCurrentUsage(PetscLogDouble *space)
{
  PetscFunctionBegin;
  *space = (PetscLogDouble)TRallocated;
  PetscFunctionReturn(PETSC_SUCCESS);
}

/*@
    PetscMallocGetMaximumUsage - gets the maximum amount of memory used that was obtained with `PetscMalloc()` at any time
        during this run, the high water mark.

    Not Collective

    Output Parameters:
.   space - maximum number of bytes ever allocated at one time

    Level: intermediate

.seealso: `PetscMallocDump()`, `PetscMallocView()`, `PetscMallocGetMaximumUsage()`, `PetscMemoryGetCurrentUsage()`,
          `PetscMallocPushMaximumUsage()`
 @*/
PetscErrorCode PetscMallocGetMaximumUsage(PetscLogDouble *space)
{
  PetscFunctionBegin;
  *space = (PetscLogDouble)TRMaxMem;
  PetscFunctionReturn(PETSC_SUCCESS);
}

/*@
    PetscMallocPushMaximumUsage - Adds another event to collect the maximum memory usage over an event

    Not Collective

    Input Parameter:
.   event - an event id; this is just for error checking

    Level: developer

.seealso: `PetscMallocDump()`, `PetscMallocView()`, `PetscMallocGetMaximumUsage()`, `PetscMemoryGetCurrentUsage()`,
          `PetscMallocPopMaximumUsage()`
 @*/
PetscErrorCode PetscMallocPushMaximumUsage(int event)
{
  PetscFunctionBegin;
  if (++NumTRMaxMems > MAXTRMAXMEMS) PetscFunctionReturn(PETSC_SUCCESS);
  TRMaxMems[NumTRMaxMems - 1]       = TRallocated;
  TRMaxMemsEvents[NumTRMaxMems - 1] = event;
  PetscFunctionReturn(PETSC_SUCCESS);
}

/*@
    PetscMallocPopMaximumUsage - collect the maximum memory usage over an event

    Not Collective

    Input Parameter:
.   event - an event id; this is just for error checking

    Output Parameter:
.   mu - maximum amount of memory malloced during this event; high water mark relative to the beginning of the event

    Level: developer

.seealso: `PetscMallocDump()`, `PetscMallocView()`, `PetscMallocGetMaximumUsage()`, `PetscMemoryGetCurrentUsage()`,
          `PetscMallocPushMaximumUsage()`
 @*/
PetscErrorCode PetscMallocPopMaximumUsage(int event, PetscLogDouble *mu)
{
  PetscFunctionBegin;
  *mu = 0;
  if (NumTRMaxMems-- > MAXTRMAXMEMS) PetscFunctionReturn(PETSC_SUCCESS);
  PetscCheck(TRMaxMemsEvents[NumTRMaxMems] == event, PETSC_COMM_SELF, PETSC_ERR_MEMC, "PetscMallocPush/PopMaximumUsage() are not nested");
  *mu = TRMaxMems[NumTRMaxMems];
  PetscFunctionReturn(PETSC_SUCCESS);
}

/*@C
   PetscMallocGetStack - returns a pointer to the stack for the location in the program a call to `PetscMalloc()` was used to obtain that memory

   Collective on `PETSC_COMM_WORLD`

   Input Parameter:
.    ptr - the memory location

   Output Parameter:
.    stack - the stack indicating where the program allocated this memory

   Level: intermediate

.seealso: `PetscMallocGetCurrentUsage()`, `PetscMallocView()`
@*/
PetscErrorCode PetscMallocGetStack(void *ptr, PetscStack **stack)
{
#if defined(PETSC_USE_DEBUG) && !defined(PETSC_HAVE_THREADSAFETY)
  TRSPACE *head;

  PetscFunctionBegin;
  head   = (TRSPACE *)(((char *)ptr) - HEADER_BYTES);
  *stack = &head->stack;
  PetscFunctionReturn(PETSC_SUCCESS);
#else
  *stack = NULL;
  return PETSC_SUCCESS;
#endif
}

/*@C
   PetscMallocDump - Dumps the currently allocated memory blocks to a file. The information
   printed is: size of space (in bytes), address of space, id of space,
   file in which space was allocated, and line number at which it was
   allocated.

   Not Collective

   Input Parameter:
.  fp  - file pointer.  If fp is NULL, stdout is assumed.

   Options Database Key:
.  -malloc_dump <optional filename> - Dumps unfreed memory during call to `PetscFinalize()`

   Level: intermediate

   Fortran Note:
   The calling sequence in Fortran is PetscMallocDump(integer ierr)
   The fp defaults to stdout.

   Notes:
     Uses `MPI_COMM_WORLD` to display rank, because this may be called in `PetscFinalize()` after `PETSC_COMM_WORLD` has been freed.

     When called in `PetscFinalize()` dumps only the allocations that have not been properly freed

     `PetscMallocView()` prints a list of all memory ever allocated

.seealso: `PetscMallocGetCurrentUsage()`, `PetscMallocView()`, `PetscMallocViewSet()`, `PetscMallocValidate()`
@*/
PetscErrorCode PetscMallocDump(FILE *fp)
{
  TRSPACE    *head;
  size_t      libAlloc = 0;
  PetscMPIInt rank;

  PetscFunctionBegin;
  PetscCallMPI(MPI_Comm_rank(MPI_COMM_WORLD, &rank));
  if (!fp) fp = PETSC_STDOUT;
  head = TRhead;
  while (head) {
    libAlloc += TRrequestedSize ? head->rsize : head->size;
    head = head->next;
  }
  if (TRallocated - libAlloc > 0) fprintf(fp, "[%d]Total space allocated %.0f bytes\n", rank, (PetscLogDouble)TRallocated);
  head = TRhead;
  while (head) {
    PetscBool isLib;

    PetscCall(PetscStrcmp(head->functionname, "PetscDLLibraryOpen", &isLib));
    if (!isLib) {
      fprintf(fp, "[%2d] %.0f bytes %s() at %s:%d\n", rank, (PetscLogDouble)(TRrequestedSize ? head->rsize : head->size), head->functionname, head->filename, head->lineno);
#if defined(PETSC_USE_DEBUG) && !defined(PETSC_HAVE_THREADSAFETY)
      PetscCall(PetscStackPrint(&head->stack, fp));
#endif
    }
    head = head->next;
  }
  PetscFunctionReturn(PETSC_SUCCESS);
}

/*@
    PetscMallocViewSet - Activates logging of all calls to `PetscMalloc()` with a minimum size to view

    Not Collective

    Input Parameter:
.   logmin - minimum allocation size to log, or `PETSC_DEFAULT`

    Options Database Key:
+  -malloc_view <optional filename> - Activates `PetscMallocView()` in `PetscFinalize()`
.  -malloc_view_threshold <min> - Sets a minimum size if -malloc_view is used
-  -log_view_memory - view the memory usage also with the -log_view option

    Level: advanced

    Notes:
    Must be called after `PetscMallocSetDebug()`

    Uses `MPI_COMM_WORLD` to determine rank because PETSc communicators may not be available

.seealso: `PetscMallocDump()`, `PetscMallocView()`, `PetscMallocViewSet()`, `PetscMallocTraceSet()`, `PetscMallocValidate()`
@*/
PetscErrorCode PetscMallocViewSet(PetscLogDouble logmin)
{
  PetscFunctionBegin;
  PetscLogMalloc = 0;
  PetscCall(PetscMemorySetGetMaximumUsage());
  if (logmin < 0) logmin = 0.0; /* PETSC_DEFAULT or PETSC_DECIDE */
  PetscLogMallocThreshold = (size_t)logmin;
  PetscFunctionReturn(PETSC_SUCCESS);
}

/*@
    PetscMallocViewGet - Determine whether calls to `PetscMalloc()` are being logged

    Not Collective

    Output Parameter
.   logging - `PETSC_TRUE` if logging is active

    Options Database Key:
.  -malloc_view <optional filename> - Activates `PetscMallocView()`

    Level: advanced

.seealso: `PetscMallocDump()`, `PetscMallocView()`, `PetscMallocTraceGet()`
@*/
PetscErrorCode PetscMallocViewGet(PetscBool *logging)
{
  PetscFunctionBegin;
  *logging = (PetscBool)(PetscLogMalloc >= 0);
  PetscFunctionReturn(PETSC_SUCCESS);
}

/*@
  PetscMallocTraceSet - Trace all calls to `PetscMalloc()`

  Not Collective

  Input Parameters:
+ viewer - The viewer to use for tracing, or NULL to use stdout
. active - Flag to activate or deactivate tracing
- logmin - The smallest memory size that will be logged

  Note:
  The viewer should not be collective.

  Level: advanced

.seealso: `PetscMallocTraceGet()`, `PetscMallocViewGet()`, `PetscMallocDump()`, `PetscMallocView()`
@*/
PetscErrorCode PetscMallocTraceSet(PetscViewer viewer, PetscBool active, PetscLogDouble logmin)
{
  PetscFunctionBegin;
  if (!active) {
    PetscLogMallocTrace = -1;
    PetscFunctionReturn(PETSC_SUCCESS);
  }
  PetscLogMallocTraceViewer = !viewer ? PETSC_VIEWER_STDOUT_SELF : viewer;
  PetscLogMallocTrace       = 0;
  PetscCall(PetscMemorySetGetMaximumUsage());
  if (logmin < 0) logmin = 0.0; /* PETSC_DEFAULT or PETSC_DECIDE */
  PetscLogMallocTraceThreshold = (size_t)logmin;
  PetscFunctionReturn(PETSC_SUCCESS);
}

/*@
  PetscMallocTraceGet - Determine whether all calls to `PetscMalloc()` are being traced

  Not Collective

  Output Parameter:
. logging - `PETSC_TRUE` if logging is active

  Options Database Key:
. -malloc_view <optional filename> - Activates PetscMallocView()

  Level: advanced

.seealso: `PetscMallocTraceSet()`, `PetscMallocViewGet()`, `PetscMallocDump()`, `PetscMallocView()`
@*/
PetscErrorCode PetscMallocTraceGet(PetscBool *logging)
{
  PetscFunctionBegin;
  *logging = (PetscBool)(PetscLogMallocTrace >= 0);
  PetscFunctionReturn(PETSC_SUCCESS);
}

/*@C
    PetscMallocView - Saves the log of all calls to `PetscMalloc()`; also calls
       `PetscMemoryGetMaximumUsage()`

    Not Collective

    Input Parameter:
.   fp - file pointer; or NULL

    Options Database Key:
.  -malloc_view <optional filename> - Activates `PetscMallocView()` in `PetscFinalize()`

    Level: advanced

   Fortran Note:
   The calling sequence in Fortran is PetscMallocView(integer ierr)
   The fp defaults to stdout.

   Notes:
     `PetscMallocDump()` dumps only the currently unfreed memory, this dumps all memory ever allocated

     `PetscMemoryView()` gives a brief summary of current memory usage

.seealso: `PetscMallocGetCurrentUsage()`, `PetscMallocDump()`, `PetscMallocViewSet()`, `PetscMemoryView()`
@*/
PetscErrorCode PetscMallocView(FILE *fp)
{
  PetscInt       i, j, n, *perm;
  size_t        *shortlength;
  int           *shortcount;
  PetscMPIInt    rank;
  PetscBool      match;
  const char   **shortfunction;
  PetscLogDouble rss;

  PetscFunctionBegin;
  PetscCallMPI(MPI_Comm_rank(MPI_COMM_WORLD, &rank));
  PetscCall(PetscFFlush(fp));

  PetscCheck(PetscLogMalloc >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "PetscMallocView() called without call to PetscMallocViewSet() this is often due to\n                      setting the option -malloc_view AFTER PetscInitialize() with PetscOptionsInsert() or PetscOptionsInsertFile()");

  if (!fp) fp = PETSC_STDOUT;
  PetscCall(PetscMemoryGetMaximumUsage(&rss));
  if (rss) {
    (void)fprintf(fp, "[%d] Maximum memory PetscMalloc()ed %.0f maximum size of entire process %.0f\n", rank, (PetscLogDouble)TRMaxMem, rss);
  } else {
    (void)fprintf(fp, "[%d] Maximum memory PetscMalloc()ed %.0f OS cannot compute size of entire process\n", rank, (PetscLogDouble)TRMaxMem);
  }
  if (PetscLogMalloc > 0) {
    shortcount = (int *)malloc(PetscLogMalloc * sizeof(int));
    PetscCheck(shortcount, PETSC_COMM_SELF, PETSC_ERR_MEM, "Out of memory");
    shortlength = (size_t *)malloc(PetscLogMalloc * sizeof(size_t));
    PetscCheck(shortlength, PETSC_COMM_SELF, PETSC_ERR_MEM, "Out of memory");
    shortfunction = (const char **)malloc(PetscLogMalloc * sizeof(char *));
    PetscCheck(shortfunction, PETSC_COMM_SELF, PETSC_ERR_MEM, "Out of memory");
    for (i = 0, n = 0; i < PetscLogMalloc; i++) {
      for (j = 0; j < n; j++) {
        PetscCall(PetscStrcmp(shortfunction[j], PetscLogMallocFunction[i], &match));
        if (match) {
          shortlength[j] += PetscLogMallocLength[i];
          shortcount[j]++;
          goto foundit;
        }
      }
      shortfunction[n] = PetscLogMallocFunction[i];
      shortlength[n]   = PetscLogMallocLength[i];
      shortcount[n]    = 1;
      n++;
    foundit:;
    }

    perm = (PetscInt *)malloc(n * sizeof(PetscInt));
    PetscCheck(perm, PETSC_COMM_SELF, PETSC_ERR_MEM, "Out of memory");
    for (i = 0; i < n; i++) perm[i] = i;
    PetscCall(PetscSortStrWithPermutation(n, (const char **)shortfunction, perm));

    (void)fprintf(fp, "[%d] Memory usage sorted by function\n", rank);
    for (i = 0; i < n; i++) (void)fprintf(fp, "[%d] %d %.0f %s()\n", rank, shortcount[perm[i]], (PetscLogDouble)shortlength[perm[i]], shortfunction[perm[i]]);
    free(perm);
    free(shortlength);
    free(shortcount);
    free((char **)shortfunction);
  }
  PetscCall(PetscFFlush(fp));
  PetscFunctionReturn(PETSC_SUCCESS);
}

/* ---------------------------------------------------------------------------- */

/*@
    PetscMallocSetDebug - Set's PETSc memory debugging

    Not Collective

    Input Parameters:
+   eachcall - checks the entire heap of allocated memory for issues on each call to `PetscMalloc()` and `PetscFree()`, slow
-   initializenan - initializes all memory with NaN to catch use of uninitialized floating point arrays

    Options Database Keys:
+   -malloc_debug <true or false> - turns on or off debugging
.   -malloc_test - turns on all debugging if PETSc was configured with debugging including -malloc_dump, otherwise ignored
.   -malloc_view_threshold t - log only allocations larger than t
.   -malloc_dump <filename> - print a list of all memory that has not been freed
.   -malloc no - (deprecated) same as -malloc_debug no
-   -malloc_log - (deprecated) same as -malloc_view

   Level: developer

    Note:
    This is called in `PetscInitialize()` and should not be called elsewhere

.seealso: `CHKMEMQ()`, `PetscMallocValidate()`, `PetscMallocGetDebug()`
@*/
PetscErrorCode PetscMallocSetDebug(PetscBool eachcall, PetscBool initializenan)
{
  PetscFunctionBegin;
  PetscCheck(PetscTrMalloc != PetscTrMallocDefault, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Cannot call this routine more than once, it can only be called in PetscInitialize()");
  PetscCall(PetscMallocSet(PetscTrMallocDefault, PetscTrFreeDefault, PetscTrReallocDefault));

  TRallocated           = 0;
  TRfrags               = 0;
  TRhead                = NULL;
  TRid                  = 0;
  TRdebugLevel          = eachcall;
  TRMaxMem              = 0;
  PetscLogMallocMax     = 10000;
  PetscLogMalloc        = -1;
  TRdebugIinitializenan = initializenan;
  PetscFunctionReturn(PETSC_SUCCESS);
}

/*@
    PetscMallocGetDebug - Indicates what PETSc memory debugging it is doing.

    Not Collective

    Output Parameters:
+    basic - doing basic debugging
.    eachcall - checks the entire memory heap at each `PetscMalloc()`/`PetscFree()`
-    initializenan - initializes memory with NaN

   Level: intermediate

   Note:
     By default, the debug version always does some debugging unless you run with -malloc_debug no

.seealso: `CHKMEMQ()`, `PetscMallocValidate()`, `PetscMallocSetDebug()`
@*/
PetscErrorCode PetscMallocGetDebug(PetscBool *basic, PetscBool *eachcall, PetscBool *initializenan)
{
  PetscFunctionBegin;
  if (basic) *basic = (PetscTrMalloc == PetscTrMallocDefault) ? PETSC_TRUE : PETSC_FALSE;
  if (eachcall) *eachcall = TRdebugLevel;
  if (initializenan) *initializenan = TRdebugIinitializenan;
  PetscFunctionReturn(PETSC_SUCCESS);
}

/*@
  PetscMallocLogRequestedSizeSet - Whether to log the requested or aligned memory size

  Not Collective

  Input Parameter:
. flg - `PETSC_TRUE` to log the requested memory size

  Options Database Key:
. -malloc_requested_size <bool> - Sets this flag

  Level: developer

.seealso: `PetscMallocLogRequestedSizeGet()`, `PetscMallocViewSet()`
@*/
PetscErrorCode PetscMallocLogRequestedSizeSet(PetscBool flg)
{
  PetscFunctionBegin;
  TRrequestedSize = flg;
  PetscFunctionReturn(PETSC_SUCCESS);
}

/*@
  PetscMallocLogRequestedSizeGet - Whether to log the requested or aligned memory size

  Not Collective

  Output Parameter:
. flg - `PETSC_TRUE` if we log the requested memory size

  Level: developer

.seealso: `PetscMallocLogRequestedSizeSetinalSizeSet()`, `PetscMallocViewSet()`
@*/
PetscErrorCode PetscMallocLogRequestedSizeGet(PetscBool *flg)
{
  PetscFunctionBegin;
  *flg = TRrequestedSize;
  PetscFunctionReturn(PETSC_SUCCESS);
}