Re: [patch 2/6] mmu_notifier: Callbacks to invalidate address ranges
From: Andrea Arcangeli <hidden>
Date: 2008-01-30 00:06:23
Also in:
kvm, lkml
On Wed, Jan 30, 2008 at 01:00:39AM +0100, Andrea Arcangeli wrote:
get_user_pages, regular linux writes don't fault unless it's explicitly writeprotect, which is mandatory in a few archs, x86 not).
actually get_user_pages doesn't fault either but it calls into set_page_dirty, however get_user_pages (unlike a userland-write) at least requires mmap_sem in read mode and the PT lock as serialization, userland writes don't, they just go ahead and mark the pte in hardware w/o faults. Anyway anonymous memory these days always mapped with dirty bit set regardless, even for read-faults, after Nick finally rightfully cleaned up the zero-page trick. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>