Sorry I didn't reply sooner. Have fun :) geir
Paulex Yang wrote: > Thank you for all your attention on this:), because seems no one > objects, I'm going to assign HARMONY-982 to myself, and start to extend > the portlib. > > Paulex Yang wrote: >> Sorry I forgot to add the prefix just now. >> >> Paulex Yang wrote: >>> Hi, all >>> >>> I raise HARMONY-982 >>> (https://issues.apache.org/jira/browse/HARMONY-982) about the portlib >>> extension on mmap. And here goes my proposal about the extension, >>> comments are welcome. >>> >>> Currently portlib has some mmap support, but the support is limited >>> in several ways: >>> 1. it only mmap in private(copy_on_write) mode >>> 2. it always mmap whole file >>> 3. it only accepts filename, but nio needs to map a already opened >>> file descriptor >>> >>> so that the Harmony's mmap is implemented in platform dependent codes >>> so far, I think these are good candidates as the portlib extension. >>> >>> To support the nio's requirement, three current mmap functions need >>> to be enhanced - hymmap_map_file, hymmap_unmap_file and >>> hymmap_capabilities, one new method is added: hymmap_msync. Please >>> see details below: >>> >>> 1. hymmap_map_file >>> >>> /** >>> * Map a part of file into memory. >>> * >>> * @param [in] portLibrary The port library >>> * @param [in] file The file descriptor/handle of >>> the already open file to be mapped >>> * @param [in] offset The file offset of the part to >>> be mapped >>> * @param [in] size The number of bytes to be >>> mapped, if zero, the whole file is mapped >>> * @param [in] mappingName The name of the file mapping >>> object to be created/opened. >>> * If a named >>> object is not required, this parameter can be specified as NULL >>> * @param [in] flags Flags relating to the mapping: >>> * @args >>> HYPORT_MMAP_FLAG_READ read only map >>> * @args >>> HYPORT_MMAP_FLAG_WRITE read/write map >>> * @args >>> HYPORT_MMAP_FLAG_COPYONWRITE copy on write map >>> * @args >>> HYPORT_MMAP_FLAG_SHARED share memory mapping with other >>> processes >>> * @args >>> HYPORT_MMAP_FLAG_PRIVATE private memory mapping, do not >>> share with other processes (implied by HYPORT_MMAP_FLAG_COPYONWRITE) >>> * >>> * @return A pointer to the start of the >>> mapped file or NULL is an error has occurred >>> */ >>> void *hymmap_map_file(HYPortLibrary portLibrary, IDATA file, U_64 >>> offset, UDATA size, const char *mappingName, U_32 flags) >>> >>> This will use CreateFileMapping() and MapViewOfFile() on Windows and >>> mmap() on Unix to map the file into the process' address space. In >>> both cases, it will return the address to which the file has been >>> mapped. >>> >>> The memory mapping API's on all platforms require an open handle/file >>> descriptor to the file to be mapped. >>> >>> The mapAddress parameter has been removed from the original >>> signature. This was an output parameter from the API containing the >>> address at which the file has been mapped. However, this is the >>> return value of the function and was therefore duplication. >>> >>> 2. hymmap_msync >>> >>> /** >>> * Synchronise updates to memory mapped file region with file on >>> disk. The call may wait for the file write >>> * to complete or this may be scheduled for a later time and the >>> function return immediately, depending on >>> * the flags setting >>> * >>> * @param [in] portLibrary The port library >>> * @param [in] start Pointer to the start of the >>> memory mapped area to be synchronised >>> * @param [in] length Length of the memory mapped >>> area to be synchronised >>> * @param [in] flags Flags controlling the >>> behaviour of the function: >>> * @args >>> HYPORT_MMAP_SYNC_WAIT Synchronous update required, function will not >>> * >>> return until file updated. Note that to achieve this on Windows >>> requires the >>> * >>> file to be opened with the FILE_FLAG_WRITE_THROUGH flag >>> * @args >>> HYPORT_MMAP_SYNC_ASYNC Asynchronous update required, function returns >>> * >>> immediately, file will be updated later >>> * @args >>> HYPORT_MMAP_SYNC_INVALIDATE Requests that other mappings of the same >>> * >>> file be invalidated, so that they can be updated with the values just >>> written >>> * >>> * @return 0 on success, -1 on failure. >>> Errors will be reported using the usual port library mechanism >>> */ >>> IDATA hymmap_msync(HYPortLibrary portLibrary, void *start, UDATA >>> length, U_32 flags) >>> >>> This function will use msync on Unix and FlushViewOfFile on Windows. >>> >>> 3. hymmap_unmap_file >>> >>> /** >>> * Unmap previously mapped memory >>> * >>> * @param [in] portLibrary The port library >>> * @param [in] start Pointer to the start of the >>> memory mapped area >>> * @param [in] size The length of the mapped area >>> */ >>> void hymmap_unmap_file(HYPortLibrary portLibrary, void *start, UDATA >>> size) >>> >>> This existing API will be changed to take the start address returned >>> from hymmap_map_file and the size of the mapped area instead of the >>> current handle. The handle is not very clear as it is the start >>> address of the mapped area (equivalent to start) on Windows and a >>> pointer to a structure containing this and the size on Unix >>> platforms. Explicitly passing the start address and length will >>> provide a clearer interface. >>> >>> 4. hymmap_capabilities >>> >>> /** >>> * Check the capabilities available for HYMMAP at runtime for the >>> current platform >>> * >>> * @param [in] portLibrary The port library >>> * >>> * @return The capabilities available on this >>> platform >>> * @args >>> HYPORT_MMAP_CAPABILITY_READ >>> * @args >>> HYPORT_MMAP_CAPABILITY_WRITE >>> * @args >>> HYPORT_MMAP_CAPABILITY_COPYONWRITE >>> */ >>> I_32 hymmap_capabilities(HYPortLibrary portLibrary) >>> >> >> > > --------------------------------------------------------------------- Terms of use : http://incubator.apache.org/harmony/mailing.html To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
