On Wed, 2012-05-16 at 21:34 +0800, Alex Shi wrote: > > So, if the minimum change of tlb->start/end can be protected by > HAVE_GENERIC_MMU_GATHER, it is safe and harmless, am I right? > safe yes, but not entirely harmless. A quick look seems to suggest you fail for VM_HUGETLB. If your mmu_gather spans a vma with VM_HUGETLB you'll do a regular range flush not a full mm flush like the other paths do. Anyway, I did a quick refresh of my series on a recent -tip tree: git://git.kernel.org/pub/scm/linux/kernel/git/peterz/mmu.git tlb-unify With that all you need is to "select HAVE_MMU_GATHER_RANGE" for x86 and implement a useful flush_tlb_range(). In particular, see: http://git.kernel.org/?p=linux/kernel/git/peterz/mmu.git;a=commitdiff;h=05e53144177e6242fda404045f50f48114bcf185;hp=2cd7dc710652127522392f4b7ecb5fa6e954941e I've slightly changed the code to address an open issue with the vm_flags tracking. We now force flush the mmu_gather whenever VM_HUGETLB flips because most (all?) archs that look at that flag expect pure huge pages and not a mixture. I've seem to have misplaced my cross-compiler set, so I've only compiled x86-64 for now. -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
