551023 - The documentation for VMPI_getPrivateResidentPageCount is unreasonable

Status: RESOLVED WONTFIX

(Tamarin Graveyard :: Virtual Machine, defect)

Description

[Lars T Hansen]

The documentation for VMPI_getPrivateResidentPageCount states:

/**
 * Method to retrieve number of VM pages in virtual address space of a process
 * @return number of pages
 * @see VMPI_getVMPageSize()
 */

Obviously the name of the function is evocative, but the documentation appears to allow a wide range of behaviors, including returning the constant 1048576 on 32-bit systems with 4KB pages.

A more reasonable constraint would be that the function return the number of mapped and committed pages that's not shared with other entities (processes / parent process).  I don't know how that would work in a plugin setting, and I don't know if it can be efficiently implemented on all platforms.  (Guessing it can't.)  The documentation should state that the call is actually surfaced as the privateMemory method on some Flash object - can't tell you which one right now - and should also state what the function can get away with in terms of imprecision, if the platform or setting does not allow for a precise implementation.

Also see bug #518351.

Comment 1

[Sylvestre Ledru [:Sylvestre]]

Tamarin isn't maintained anymore. WONTFIX remaining bugs.