-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Wow.
I'd heard that there was a way to set 3.5/0.5 GiB split, and that there was a patch that removed the split and isolated the kernel (but that was slow), so I was just curious about all this stuff with people screaming about how tight 4G of VM is vs a half gig or a gig that can be freed up. Josh Boyer wrote: > On Fri, 2005-01-28 at 15:06 -0500, John Richard Moser wrote: > >>-----BEGIN PGP SIGNED MESSAGE----- >>Hash: SHA1 >> >>Can someone give me a layout of what exactly is up there? I got the >>basic idea >> >>K 4G >>A 3G >>A 2G >>A 1G >> >>App has 3G, kernel has 1G at the top of VM on x86 (dunno about x86_64). >> >>So what's the layout of that top 1G? What's it all used for? Is there >>some obscene restriction of 1G of shared memory or something that gets >>mapped up there? >> >>How much does it need, and why? What, if anything, is variable and >>likely to do more than 10 or 15 megs of variation? > > > Because of various reasons. Normal kernel space virtual addresses > usually start at 0xc0000000, which is where the 3GiB userspace > restriction comes from. > > Then there is the vmalloc virtual address space, which usually starts at > a higher address than a normal kernel address. Along the same lines are > ioremap addresses, etc. > > Poke around in the header files. I bet you'll find lots of reasons. > > josh > > - -- All content of all messages exchanged herein are left in the Public Domain, unless otherwise explicitly stated. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.0 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://enigmail.mozdev.org iD8DBQFB+qUdhDd4aOud5P8RAmU8AJ9fRQi4A+yIVaXdv/oWlPIqObROPQCfUgvU KAsRKxYgSTWVecLsZZCvXgE= =v+fM -----END PGP SIGNATURE----- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
