Messages in this thread | | | Date | Tue, 28 Aug 2018 15:48:42 +0200 | From | Peter Zijlstra <> | Subject | Re: [RFC PATCH 08/11] asm-generic/tlb: Track freeing of page-table directories in struct mmu_gather |
| |
On Tue, Aug 28, 2018 at 03:46:38PM +0200, Peter Zijlstra wrote: > On Mon, Aug 27, 2018 at 02:44:57PM +1000, Nicholas Piggin wrote: > > > powerpc may be able to use the unmap granule thing to improve > > its page size dependent flushes, but it might prefer to go > > a different way and track start-end for different page sizes. > > I don't really see how tracking multiple ranges would help much with > THP. The ranges would end up being almost the same if there is a good > mix of page sizes. > > But something like: > > void tlb_flush_one(struct mmu_gather *tlb, unsigned long addr) > { > if (tlb->cleared_ptes && (addr << BITS_PER_LONG - PAGE_SHIFT)) > tblie_pte(addr); > if (tlb->cleared_pmds && (addr << BITS_PER_LONG - PMD_SHIFT)) > tlbie_pmd(addr); > if (tlb->cleared_puds && (addr << BITS_PER_LONG - PUD_SHIFT)) > tlbie_pud(addr); > }
Sorry, those all should (of course) be !(addr << ...).
> void tlb_flush_range(struct mmu_gather *tlb) > { > unsigned long stride = 1UL << tlb_get_unmap_shift(tlb); > unsigned long addr; > > for (addr = tlb->start; addr < tlb->end; addr += stride) > tlb_flush_one(tlb, addr); > > ptesync(); > }
And one could; like x86 has; add a threshold above which you just kill the complete mm.
| |