Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1637164

Re: [RFC 00/10] x86 TLB flush cleanups, moving toward PCID support

Show all headers | View raw

* Andy Lutomirski <luto@kernel.org> wrote:

> As I've been working on polishing my PCID code, a major problem I've
> encountered is that there are too many x86 TLB flushing code paths and
> that they have too many inconsequential differences.  The result was
> that earlier versions of the PCID code were a colossal mess and very
> difficult to understand.
> 
> This series goes a long way toward cleaning up the mess.  With all the
> patches applied, there is a single function that contains the meat of
> the code to flush the TLB on a given CPU, and all the tlb flushing
> APIs call it for both local and remote CPUs.
> 
> This series should only adversely affect the kernel in a couple of
> minor ways:
> 
>  - It makes smp_mb() unconditional when flushing TLBs.  We used to
>    use the TLB flush itself to mostly avoid smp_mb() on the initiating
>    CPU.
> 
>  - On UP kernels, we lose the dubious optimization of inlining nerfed
>    variants of all the TLB flush APIs.  This bloats the kernel a tiny
>    bit, although it should increase performance, since the SMP
>    versions were better.
> 
> Patch 10 in here is a little bit off topic.  It's a cleanup that's
> also needed before PCID can go in, but it's not directly about
> TLB flushing.
> 
> Thoughts?

Looks really nifty! The diffstat alone appears to be worth it:

 18 files changed, 334 insertions(+), 408 deletions(-)

Will have a closer look next week.

Thanks,

	Ingo

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[RFC 00/10] x86 TLB flush cleanups, moving toward PCID support Andy Lutomirski <luto@kernel.org> - 2017-05-08 00:10 +0200
  [RFC 03/10] x86/mm: Make the batched unmap TLB flush API more generic Andy Lutomirski <luto@kernel.org> - 2017-05-08 00:10 +0200
    Re: [RFC 03/10] x86/mm: Make the batched unmap TLB flush API more  generic Dave Hansen <dave.hansen@intel.com> - 2017-05-08 17:40 +0200
      Re: [RFC 03/10] x86/mm: Make the batched unmap TLB flush API more generic Andy Lutomirski <luto@kernel.org> - 2017-05-09 15:10 +0200
        Re: [RFC 03/10] x86/mm: Make the batched unmap TLB flush API more  generic Mel Gorman <mgorman@suse.de> - 2017-05-09 16:50 +0200
        Re: [RFC 03/10] x86/mm: Make the batched unmap TLB flush API more  generic Dave Hansen <dave.hansen@intel.com> - 2017-05-09 19:20 +0200
          Re: [RFC 03/10] x86/mm: Make the batched unmap TLB flush API more generic Andy Lutomirski <luto@kernel.org> - 2017-05-10 01:00 +0200
  [RFC 07/10] x86/mm: Use new merged flush logic in arch_tlbbatch_flush() Andy Lutomirski <luto@kernel.org> - 2017-05-08 00:10 +0200
  [RFC 04/10] x86/mm: Pass flush_tlb_info to flush_tlb_others() etc Andy Lutomirski <luto@kernel.org> - 2017-05-08 00:10 +0200
    Re: [RFC 04/10] x86/mm: Pass flush_tlb_info to flush_tlb_others() etc Nadav Amit <nadav.amit@gmail.com> - 2017-05-11 22:10 +0200
  [RFC 05/10] x86/mm: Change the leave_mm() condition for local TLB flushes Andy Lutomirski <luto@kernel.org> - 2017-05-08 00:10 +0200
  [RFC 02/10] x86/mm: Reduce indentation in flush_tlb_func() Andy Lutomirski <luto@kernel.org> - 2017-05-08 00:10 +0200
  [RFC 08/10] x86/mm: Remove the UP tlbflush code; always use the formerly SMP code Andy Lutomirski <luto@kernel.org> - 2017-05-08 00:10 +0200
  [RFC 01/10] x86/mm: Reimplement flush_tlb_page() using flush_tlb_mm_range() Andy Lutomirski <luto@kernel.org> - 2017-05-08 00:10 +0200
    Re: [RFC 01/10] x86/mm: Reimplement flush_tlb_page() using  flush_tlb_mm_range() Borislav Petkov <bp@suse.de> - 2017-05-11 19:50 +0200
  [RFC 10/10] x86,kvm: Teach KVM's VMX code that CR3 isn't a constant Andy Lutomirski <luto@kernel.org> - 2017-05-08 00:20 +0200
  [RFC 06/10] x86/mm: Refactor flush_tlb_mm_range() to merge local and remote cases Andy Lutomirski <luto@kernel.org> - 2017-05-08 00:20 +0200
  Re: [RFC 00/10] x86 TLB flush cleanups, moving toward PCID support Linus Torvalds <torvalds@linux-foundation.org> - 2017-05-08 01:00 +0200
  Re: [RFC 00/10] x86 TLB flush cleanups, moving toward PCID support Ingo Molnar <mingo@kernel.org> - 2017-05-08 01:50 +0200
  Re: [RFC 00/10] x86 TLB flush cleanups, moving toward PCID support Nadav Amit <nadav.amit@gmail.com> - 2017-05-08 18:40 +0200
    Re: [RFC 00/10] x86 TLB flush cleanups, moving toward PCID support Andy Lutomirski <luto@kernel.org> - 2017-05-09 14:50 +0200

csiph-web