On 02/10/2012 01:14 PM, Seth Jennings wrote: > On 02/08/2012 03:04 PM, Benjamin Herrenschmidt wrote: >> >>> You can look at https://lkml.org/lkml/2012/1/9/389 in zsmalloc-main.c, >>> zs_[un]map_object() functions for the currently uses of set_pte() and >>> __flush_tlb_one(). >>> >>>> set_pte() is long gone on all archs really (or if it's still there it's >>>> not meant to be used as is), use set_pte_at(). >>> >>> Problem with set_pte_at() for us is that we don't have an mm_struct to pass >>> because the mapping is not for a userspace process but for the kernel >>> itself. >> >> Then use init_mm > > Thanks, that's what I was looking for. > >>> However, I do think this is the portable function we need to be using. Just >>> need to figure out what to pass in for the mm_struct param. >>> >>>> __flush_tlb_one() doesn't mean anything as an arch independent >>>> functionality. We have a local_flush_tlb_page() that -might- do what you >>>> want but why in hell is that patch not using proper existing >>>> interfaces ? >>> >>> flush_tlb_page() is the portable function we should be using. However, >>> again, it requires a vma_area_struct. I'm not sure what we should be >>> passing there. >> >> Do you need this to be CPU local flush or global ? In the later, >> flush_tlb_kernel_range() is the right API. >> >> If you want per-cpu, we'll have to add a new arch hook. > > We have interrupts disabled, due to the get_cpu_var() on the percpu variable > zs_map_area in zs_map_object(), while the allocation is mapped. So a CPU > local > would be what we need.
Hey Ben, Just wanted to bump you again about this. You mentioned that if I wanted to do a cpu-local flush of a single tlb entry, that there would have to be a new hook. Is that right? I've been looking through the powerpc arch and I thought that I might have found the power analog to __flush_tlb_one() for x86 in local_flush_tlb_page() with a NULL vma argument. This doesn't seem to work though, as indicated by a crash when I tried it. After looking in tlbflush.h again, it seems that local_flush_tlb_page() is a no-op when CONFIG_PPC_STD_MMU_64 is set, as are almost ALL of the tlb flushing functions... which makes no sense to me. Any help you (or anyone) can give me would be greatly appreciated. -- Seth _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
