AquariusXu

Hi All, I have a question about MmTrimAllSystemPagableMemory() function. Winodws Internal says: Force IRQL Checking One of the most common device driver bugs occurs when a driver accesses pageable data or code when the processor on which the device driver is executing is at an elevated IRQL. As explained in Chapter 3, the memory manager can't service a page fault when the IRQL is DPC/dispatch level or above. The system often doesn't detect instances of a device driver accessing pageable data when the processor is executing at a high IRQL level because the pageable data being accessed happens to be physically resident at the time. At other times, however, the data might be paged out, which results in a system crash with the stop code IRQL_NOT_LESS_OR_EQUAL (that is, the IRQL wasn't less than or equal to the level required for the operation attempted—in this case, accessing pageable memory). Although testing device drivers for this kind of bug is usually difficult, Driver Verifier makes it easy. If you select the Force IRQL Checking option, Driver Verifier forces all kernel-mode pageable code and data out of the system working set whenever a device driver under verification raises the IRQL. The internal function that does this is MmTrimAllSystemPagableMemory. With this setting enabled, whenever a device driver under verification accesses pageable memory when the IRQL is elevated, the system instantly detects the violation and the resulting system crash identifies the faulty driver. However I checked the Driver verifier's setting, it doesn't enable ''force IRQL checking'', but this function is still be called, are there any other usage of this function?? What does this function do, when it is called?? Thanks AquariusXu ==Y(滕),Apple.i.M== XCR