On 29 June 2011 12:08, Mulyadi Santosa <[email protected]> wrote:
> Hi :) > > On Wed, Jun 29, 2011 at 13:30, piyush moghe <[email protected]> wrote: > > Thanks Mulyadi and Prabhu for your enlightening description. > > You welcome :) > > > What a plight!!! memory has become soo cheap nowadays that I don't have > less > > than 1GB system and difficult to find someone in my knowledge having less > > than 1 GB memory. > > In embedded world, it's still common scenario.... so it depends on > which side we see it :) That's the flexibility Linux kernel tries to > show...it does well on big memory machine...but it can also run in > small amount of memory... of course, with the right user space > applications :) (hint: Linux slitaz, puppy, tiny core...) > > > > Although does this means that pages in FCOM will never have page fault? > > Everything mapped in kernel space ( I stress the word "mapped") is > designed to stay all the time in RAM in Linux kernel context. So based > on that AFAIK, we won't get page fault in kernel space. This is > strictly design choice IMHO. > > >and > > if this is true is this the reason why we assign NULL to memory > descriptor ( > > mm_struct ) for kernel threads? > > because kernel threads don't need to have specific address space owned > to them. They can simply "borrow" last scheduled process' address > space. After all, they just operate in kernel space, which is the same > for all processes, be it kernel threads or normal task. > Thanks Mulyadi for your clarifications! I am not getting the idea of "borrowing" last run process's address space. A kernel thread refers only the addresses in kernel's address space (low-mem area) which is mapped already, isnt it? How does the address space of last run task comes into picture? > > -- > regards, > > Mulyadi Santosa > Freelance Linux trainer and consultant > > blog: the-hydra.blogspot.com > training: mulyaditraining.blogspot.com > > _______________________________________________ > Kernelnewbies mailing list > [email protected] > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > -- Regards, Paraneetharan C
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