On Mon, Mar 03, 2025 at 02:40:49PM -0800, Dave Hansen wrote:
> On 2/25/25 19:00, Rik van Riel wrote:
> > static inline void __invlpgb_flush_user_nr_nosync(unsigned long pcid,
> > unsigned long addr,
> > u16 nr,
> > - bool pmd_stride)
> > + bool pmd_stride,
> > + bool freed_tables)
> > {
> > - __invlpgb(0, pcid, addr, nr, pmd_stride, INVLPGB_PCID | INVLPGB_VA);
> > + u8 flags = INVLPGB_PCID | INVLPGB_VA;
> > +
> > + if (!freed_tables)
> > + flags |= INVLPGB_FINAL_ONLY;
> > +
> > + __invlpgb(0, pcid, addr, nr, pmd_stride, flags);
> > }
>
> I'm not sure this is OK.
>
> Think of a hugetlbfs mapping with shared page tables. Say you had a
> 1GB-sized and 1GB-aligned mapping. It might zap the one PUD that it
> needs, set tlb->cleared_puds=1 but it never sets ->freed_tables because
> it didn't actually free the shared page table page.
>
> I'd honestly just throw this patch out of the series for now. All of the
> other TLB invalidation that the kernel does implicitly toss out the
> mid-level paging structure caches.
Right, I guess we can revisit this later, once the dust settles.
Thx.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
