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November 2008
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2008.11.14 22:13 "Re: Memory leak (TIFFOpen, TIFFReadTile)?", by Phillip Crews
Craig Bruce wrote: > Frank Warmerdam <warmerdam@pobox.com> wrote: > > >> It really sounds like you are mixup up process size with heap memory use. >> Many tools that report a processes size will also report all the memory >> currently used by pages of a disk file that are paged into memory as part >> of the io subsystem. This is not real heap use, and the memory will be >> released by the operating system as soon as it is needed for something >> else. Till then the disk pages are left in memory in case they are needed >> again. This is consistent with the memory use dropping on close. >> > > I have found that memory-mapped I/O is completely FUBARed, even on Linux. > Even if the kernel is ultimately going to release the memory, the system > still thrashes like crazy. It really shouldn't be the default mode > for TIFFOpen(). > > To avoid this problem, I call TIFFOpen() with a mode of "rCm". This makes > image reading work as expected. > I use "rCm" for TIFF files above a certain (rather artbitrary) size -- 80MB in my case -- for the same reason, but as long as memory is plentiful, memory mapped files are somewhat faster. I also used to use 'rm' for smaller files on some Windows operating system (ME I think) because memory mapped files were left locked. - Phillip