[NTOS:MM] Implement PeakCommitment (MmPeakCommitment, MmTotalCommittedPages) (#4650)

And return the corresponding values in SystemPerformanceInformation.
Lockless updating counters suggestion by Thomas Faber.

ntoskrnl/ex/sysinfo.c

@@ -714,13 +714,8 @@ QSI_DEF(SystemPerformanceInformation)
     }
 
     Spi->AvailablePages = (ULONG)MmAvailablePages;
-    /*
+
-     *   Add up all the used "Committed" memory + pagefile.
+    Spi->CommittedPages = MmTotalCommittedPages;
-     *   Not sure this is right. 8^\
-     */
-    Spi->CommittedPages = MiMemoryConsumers[MC_SYSTEM].PagesUsed +
-                          MiMemoryConsumers[MC_USER].PagesUsed +
-                          MiUsedSwapPages;
     /*
      *  Add up the full system total + pagefile.
      *  All this make Taskmgr happy but not sure it is the right numbers.
@@ -728,7 +723,7 @@ QSI_DEF(SystemPerformanceInformation)
      */
     Spi->CommitLimit = MmNumberOfPhysicalPages + MiFreeSwapPages + MiUsedSwapPages;
 
-    Spi->PeakCommitment = 0; /* FIXME */
+    Spi->PeakCommitment = MmPeakCommitment;
     Spi->PageFaultCount = 0; /* FIXME */
     Spi->CopyOnWriteCount = 0; /* FIXME */
     Spi->TransitionCount = 0; /* FIXME */

ntoskrnl/include/internal/mm.h

@@ -866,6 +866,33 @@ NTAPI
 MmDeleteKernelStack(PVOID Stack,
                     BOOLEAN GuiStack);
 
+/* balance.c / pagefile.c******************************************************/
+
+inline VOID UpdateTotalCommittedPages(LONG Delta)
+{
+    /*
+     * Add up all the used "Committed" memory + pagefile.
+     * Not sure this is right. 8^\
+     * MmTotalCommittedPages should be adjusted consistently with
+     * other counters at different places.
+     *
+       MmTotalCommittedPages = MiMemoryConsumers[MC_SYSTEM].PagesUsed +
+                               MiMemoryConsumers[MC_USER].PagesUsed +
+                               MiUsedSwapPages;
+     */
+    
+    /* Update Commitment */
+    SIZE_T TotalCommittedPages = InterlockedExchangeAddSizeT(&MmTotalCommittedPages, Delta) + Delta;
+
+    /* Update Peak = max(Peak, Total) in a lockless way */
+    SIZE_T PeakCommitment = MmPeakCommitment;
+    while (TotalCommittedPages > PeakCommitment &&
+           InterlockedCompareExchangeSizeT(&MmPeakCommitment, TotalCommittedPages, PeakCommitment) != PeakCommitment)
+    {
+        PeakCommitment = MmPeakCommitment;
+    }
+}
+
 /* balance.c *****************************************************************/
 
 CODE_SEG("INIT")

ntoskrnl/mm/balance.c

@@ -81,6 +81,7 @@ MmReleasePageMemoryConsumer(ULONG Consumer, PFN_NUMBER Page)
     }
 
     (void)InterlockedDecrementUL(&MiMemoryConsumers[Consumer].PagesUsed);
+    UpdateTotalCommittedPages(-1);
 
     OldIrql = MiAcquirePfnLock();
 
@@ -284,6 +285,7 @@ MmRequestPageMemoryConsumer(ULONG Consumer, BOOLEAN CanWait,
 
     /* Update the target */
     InterlockedIncrementUL(&MiMemoryConsumers[Consumer].PagesUsed);
+    UpdateTotalCommittedPages(1);
 
     /*
      * Actually allocate the page.

ntoskrnl/mm/pagefile.c

@@ -295,6 +295,7 @@ MmFreeSwapPage(SWAPENTRY Entry)
 
     MiFreeSwapPages++;
     MiUsedSwapPages--;
+    UpdateTotalCommittedPages(-1);
 
     KeReleaseGuardedMutex(&MmPageFileCreationLock);
 }
@@ -329,6 +330,8 @@ MmAllocSwapPage(VOID)
             }
             MiUsedSwapPages++;
             MiFreeSwapPages--;
+            UpdateTotalCommittedPages(1);
+
             KeReleaseGuardedMutex(&MmPageFileCreationLock);
 
             entry = ENTRY_FROM_FILE_OFFSET(i, off + 1);