Hi :) On Sat, Sep 10, 2011 at 08:16, Zheng Da <zhengda1936@xxxxxxxxx> wrote: > Hello, > > I need to allocate fairly a large piece of memory, about 128KB or > 256KB. 128 K? Are you sure? That doesn't sound too big for me...but I might be wrong here..... if you say 4 megabyte, now that's big... >I tried to use kmalloc, and it sometimes fails, but vmalloc in > this case usually still work. easy to guess, vmalloc doesn't care if it's not physically contigous...only virtually contigous > But I'm not sure how costly vmalloc is. As far as I know, vmalloc > needs to change the page table, and thus might need to invalidate TLB. > It seems quite expensive. If it is, maybe I can allocate memory with > kmalloc first, and then try to use vmalloc if kmalloc fails. Any > suggestions? invalidating page table, at some point yes. Also searching non physically contigous could be hard too. But again, this is your last resort to gain such a large memory area. just my 2 cents idea... -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
