On Tue, Mar 3, 2009 at 3:29 PM, Peter Teoh <htmldeveloper@xxxxxxxxx> wrote: > - Show quoted text - > On Tue, Mar 3, 2009 at 11:39 AM, NAHieu <nahieu@xxxxxxxxx> wrote: >> On Tue, Mar 3, 2009 at 12:16 PM, Peter Teoh <htmldeveloper@xxxxxxxxx> wrote: >>> This is the first time I have seen the word "unity-mapping"......if it >>> is your invention....congratulations!!!! U have created a new term. >> >> so you learned a new term today :-). but i agree that it is not >> popular, and it confused me at first. >> >> so the more popular one is "identity mapping", right? >> >> that is not my term, but somebody else. I read that on internet somewhere ... >> >>> >>> Usually I heard of "identity mapping", "direct mapping", linear >>> mapping, vs "non-linear mapping". The formula is basically >>> equivalent to __pa(), and all the different variation: __va(), >>> virt_to_page(), pfn_to_kaddr() etc. It is all just using a >>> straightforward formula. This is because virtual address and >>> physical addr are inter-convertible directly in the ZONE_NORMAL range. >>> But not in the ZONE_HIGH area. kmalloc() always returned addresses >>> in these range. All the confusing API like pud*, pgd*, pmd*() API >>> also hinges on this characteristic to convert directly between >>> physical and virtual, or to extract out page frame number, PTE etc >>> from the virtual/physical addresses. >> >> OK, so the difference between kmalloc and vmalloc in term of address >> they return: >> - kmalloc() always return addresses in ZONE_NORMAL >> - vmalloc() always returns addresses in ZONE_HIGH >> >> Could you confirm that is correct? > > to the best of my knowledge....i think yes. > >> >> So my question now is: what is ZONE_NORMAL range? I mean from what >> address to what address? >> > > eh.....check header file definition......it varies from arch to arch, > and may be modified at bootup time via some parameter as well. but > don't have to know either - cannot find any reason for that. can i > know why did u ask? I am working on a tool to analyze the kernel memory, so I need to understand how kernel manages and layouts its memory. Thanks, H -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
