C++ (Cpp) IsLowMemory Examples

Example #1

File: balloon.c Project: bloomier/kvm-guest-drivers-windows

VOID
BalloonFill(
    IN WDFOBJECT WdfDevice,
    IN size_t num)
{
    PMDL                pPageMdl;
    PHYSICAL_ADDRESS    LowAddress;
    PHYSICAL_ADDRESS    HighAddress;
    PPAGE_LIST_ENTRY    pNewPageListEntry;
    PDEVICE_CONTEXT     devCtx = GetDeviceContext(WdfDevice);
    ULONG               pages_per_request = PAGE_SIZE/sizeof(PFN_NUMBER);

    TraceEvents(TRACE_LEVEL_INFORMATION, DBG_HW_ACCESS, "--> %s\n", __FUNCTION__);

    LowAddress.QuadPart = 0;
    HighAddress.QuadPart = (ULONGLONG)-1;

    num = min(num, pages_per_request);
    TraceEvents(TRACE_LEVEL_INFORMATION, DBG_HW_ACCESS, "--> BalloonFill num = %d\n", num);

    for (devCtx->num_pfns = 0; devCtx->num_pfns < num; devCtx->num_pfns++)
    {
        if(IsLowMemory(WdfDevice))
        {
           TraceEvents(TRACE_LEVEL_WARNING, DBG_HW_ACCESS,
                "LowMemoryCondition event was set to signaled,allocations stops, BalPageCount=%d\n", devCtx->num_pages);
           break;
        }
        pPageMdl = MmAllocatePagesForMdl(
                                        LowAddress,
                                        HighAddress,
                                        LowAddress,
                                        PAGE_SIZE
                                        );
        if (pPageMdl == NULL)
        {
            TraceEvents(TRACE_LEVEL_WARNING, DBG_HW_ACCESS,
                 "Balloon MDL Page Allocation Failed!!!, BalPageCount=%d\n", devCtx->num_pages);
            break;
        }

        if (MmGetMdlByteCount(pPageMdl) != PAGE_SIZE)
        {
            TraceEvents(TRACE_LEVEL_WARNING, DBG_HW_ACCESS,
                 "Balloon MDL Page Allocation < PAGE_SIZE =%d, Failed!!!, BalPageCount=%d\n",MmGetMdlByteCount(pPageMdl), devCtx->num_pages);
            MmFreePagesFromMdl(pPageMdl);
            ExFreePool(pPageMdl);
            break;
        }

        pNewPageListEntry = (PPAGE_LIST_ENTRY)ExAllocateFromNPagedLookasideList(&devCtx->LookAsideList);
        if (pNewPageListEntry == NULL)
        {
            TraceEvents(TRACE_LEVEL_ERROR, DBG_HW_ACCESS, "List Entry Allocation Failed!!!\n");
            MmFreePagesFromMdl(pPageMdl);
            ExFreePool(pPageMdl);
            break;
        }

        pNewPageListEntry->PageMdl = pPageMdl;
        pNewPageListEntry->PagePfn = devCtx->pfns_table[devCtx->num_pfns] = *MmGetMdlPfnArray(pPageMdl);

        PushEntryList(&devCtx->PageListHead, &(pNewPageListEntry->SingleListEntry));
        devCtx->num_pages++;
    }

    if (devCtx->num_pfns > 0)
    {
        BalloonTellHost(WdfDevice, devCtx->InfVirtQueue);
    }
}

Example #2

File: balloon.c Project: represent-communications/kvm-guest-drivers-windows

VOID
BalloonFill(
    IN WDFOBJECT WdfDevice,
    IN size_t num)
{
    PDEVICE_CONTEXT ctx = GetDeviceContext(WdfDevice);
    PHYSICAL_ADDRESS LowAddress;
    PHYSICAL_ADDRESS HighAddress;
    PHYSICAL_ADDRESS SkipBytes;
    PPAGE_LIST_ENTRY pNewPageListEntry;
    PMDL pPageMdl;

    TraceEvents(TRACE_LEVEL_VERBOSE, DBG_HW_ACCESS, "--> %s\n", __FUNCTION__);

    ctx->num_pfns = 0;

    if (IsLowMemory(WdfDevice))
    {
        TraceEvents(TRACE_LEVEL_WARNING, DBG_HW_ACCESS,
            "Low memory. Allocated pages: %d\n", ctx->num_pages);
        return;
    }

    num = min(num, PAGE_SIZE / sizeof(PFN_NUMBER));
    TraceEvents(TRACE_LEVEL_INFORMATION, DBG_HW_ACCESS,
        "Inflate balloon with %d pages.\n", num);

    LowAddress.QuadPart = 0;
    HighAddress.QuadPart = (ULONGLONG)-1;
    SkipBytes.QuadPart = 0;

#if (NTDDI_VERSION < NTDDI_WS03SP1)
    pPageMdl = MmAllocatePagesForMdl(LowAddress, HighAddress, SkipBytes,
        num * PAGE_SIZE);
#else
    pPageMdl = MmAllocatePagesForMdlEx(LowAddress, HighAddress, SkipBytes,
        num * PAGE_SIZE, MmNonCached, MM_DONT_ZERO_ALLOCATION);
#endif

    if (pPageMdl == NULL)
    {
        TraceEvents(TRACE_LEVEL_WARNING, DBG_HW_ACCESS,
            "Failed to allocate pages.\n");
        return;
    }

    if (MmGetMdlByteCount(pPageMdl) != (num * PAGE_SIZE))
    {
        TraceEvents(TRACE_LEVEL_WARNING, DBG_HW_ACCESS,
            "Not all requested memory was allocated (%d/%d).\n",
            MmGetMdlByteCount(pPageMdl), num * PAGE_SIZE);
        MmFreePagesFromMdl(pPageMdl);
        ExFreePool(pPageMdl);
        return;
    }

    pNewPageListEntry = (PPAGE_LIST_ENTRY)ExAllocateFromNPagedLookasideList(
        &ctx->LookAsideList);

    if (pNewPageListEntry == NULL)
    {
        TraceEvents(TRACE_LEVEL_ERROR, DBG_HW_ACCESS,
            "Failed to allocate list entry.\n");
        MmFreePagesFromMdl(pPageMdl);
        ExFreePool(pPageMdl);
        return;
    }

    pNewPageListEntry->PageMdl = pPageMdl;
    PushEntryList(&ctx->PageListHead, &(pNewPageListEntry->SingleListEntry));

    ctx->num_pfns = num;
    ctx->num_pages += ctx->num_pfns;

    RtlCopyMemory(ctx->pfns_table, MmGetMdlPfnArray(pPageMdl),
        ctx->num_pfns * sizeof(PFN_NUMBER));

    BalloonTellHost(WdfDevice, ctx->InfVirtQueue);

    TraceEvents(TRACE_LEVEL_VERBOSE, DBG_HW_ACCESS, "<-- %s\n", __FUNCTION__);
}