Hi, Aris, The documentation about mmap <http://pubs.opengroup.org/onlinepubs/007908799/xsh/mmap.html> indicates that MAP_PRIVATE and MAP_SHARED affects the write operations only. I am under the impression that for read-only file maps, the system will automatically share the content -- therefore nothing is said about this case.
If you know for sure that MAP_SHARED is necessary for read-only maps to be shared, let me know, I will change the flag from MAP_PRIVATE to MAP_SHARED. John On 2/10/15 6:15 AM, Aris Setyawan wrote: > I have checked the code. Yes, the mmap opened readonly, "read_only (@c > opt = 0) mode". > But this lead to call mmap using MAP_PRIVATE flag (not shared). > > To share mmap between process, one must mmap using MAP_SHARED. > So I think this mmap wouldn't be shared between process. > > Is this expected behavior? > > -Aris > > On 2/9/15, K. John Wu <[email protected]> wrote: >> Hi, Aris, >> >> In all cases, FastBit is doing memory map on read-only content. >> Therefore, the system should be able to safely share the content among >> different processes. Hope this helps. >> >> John >> >> >> On 2/8/15 7:17 PM, Aris Setyawan wrote: >>> Hi John, >>> >>> Is fastbit memory mapped file, shared between process? >>> >>> I plan to use fastbit from php-apache, which have multiple process >>> architecture. >>> If the memory mapped file shared, I can save a lot of memory. >>> >>> >>> Regards, >>> -aris. >>> _______________________________________________ >>> FastBit-users mailing list >>> [email protected] >>> https://hpcrdm.lbl.gov/cgi-bin/mailman/listinfo/fastbit-users >>> >> _______________________________________________ >> FastBit-users mailing list >> [email protected] >> https://hpcrdm.lbl.gov/cgi-bin/mailman/listinfo/fastbit-users >> > _______________________________________________ > FastBit-users mailing list > [email protected] > https://hpcrdm.lbl.gov/cgi-bin/mailman/listinfo/fastbit-users > _______________________________________________ FastBit-users mailing list [email protected] https://hpcrdm.lbl.gov/cgi-bin/mailman/listinfo/fastbit-users
