On Monday, February 14, 2011 10:12:59 pm beezarliu wrote: > On 2011-02-14 22:56:28, John Baldwin wrote: > >On Monday, February 14, 2011 4:18:50 am beezarliu wrote: > >> Hackers, > >> > >> I want to access a userland share memory in a kernel thread. > >> So I tried to map the share memory to the kernel space. > >> The basic idea is to map the shm_object into kernel_map > >> when the share memory is created. > >> > >> Using the following patch, I found the vm_object in kernel_map, > >> and the vm_object in the address space of userland process are the same. > >> But their content in the kernel and userland address mapped are different. > >> > >> It's very strang since they are exactly the same vm_object. > >> Do I miss something, please help. > > > >Hmm, this is a bit of code I use for something similar to map a VM object > >into > >the kernel. It does not use vm_page_grab() directly though: > > > Initially, I wanted to allocate all the pages needed when the share memory is > created, > in order to reduce page fault at the time it's used. > This seems to be an extra step. :( > > John, thank you very much!
I think vm_map_wire() will find pages for you when it wires the object. -- John Baldwin _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "freebsd-hackers-unsubscr...@freebsd.org"
