Thank you, peter. Yes, graphical guys ask me the same questions, and the other device drivers which don't support scatter buffer also have this doubt.
Best Regards, Peter Chen On Mon, 2009-03-30 at 11:53 -0400, Peter Teoh wrote: > On Mon, Mar 30, 2009 at 8:13 AM, Peter Chen <[email protected]> wrote: > > Hi all, > > > > I have two questions about alloc continual physical memory, hope you can > > give me some tips. > > > > 1. How biggest continual physical memory the kernel can be ensured to give > > during the kernel running? > > 2. What is the threshold value for alloc_page and kmalloc? > > > > both asking the same question. > > that is a difficult question to answer. it start changing when the > system starts running, and perhaps the contiguity property is needed > in graphic card drivers - are u in that area? > but check this out: > > http://lwn.net/Articles/211505/ > > it is trying to meet what you are asking - getting the memory to be > less fragmented as much as possible. and look into the page > migration (http://lwn.net/Articles/160201/) codes as well. > > BUT SOrry...i cannot answer your question. just have to call > alloc_pages() or kmalloc()...and if it returned, contiguity is > guaranteed. as for interpretation of /proc/slabinfo and its use to > answer your question.....i think there may be a way.....but i am not > sure. > > > This memory is demanded to alloc dymatically, not using alloc_bootmem during > > the system bootup. > > > > Thank you in advance > > > > Best Regards, > > Peter Chen > > >
