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  1. 25 Nov, 2021 4 commits
    • Julia Lawall's avatar
      powerpc/cell: add missing of_node_put · a841fd00
      Julia Lawall authored 
      for_each_node_by_name performs an of_node_get on each iteration, so
a break out of the loop requires an of_node_put.

A simplified version of the semantic patch that fixes this problem is as
follows (http://coccinelle.lip6.fr):

// <smpl>
@@
expression e,e1;
local idexpression n;
@@

 for_each_node_by_name(n, e1) {
   ... when != of_node_put(n)
       when != e = n
(
   return n;
|
+  of_node_put(n);
?  return ...;
)
   ...
 }
// </smpl>
Signed-off-by: default avatarJulia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1448051604-25256-7-git-send-email-Julia.Lawall@lip6.fr
      a841fd00
    • Julia Lawall's avatar
      powerpc/powernv: add missing of_node_put · 7d405a93
      Julia Lawall authored 
      for_each_compatible_node performs an of_node_get on each iteration, so
a break out of the loop requires an of_node_put.

A simplified version of the semantic patch that fixes this problem is as
follows (http://coccinelle.lip6.fr):

// <smpl>
@@
local idexpression n;
expression e;
@@

 for_each_compatible_node(n,...) {
   ...
(
   of_node_put(n);
|
   e = n
|
+  of_node_put(n);
?  break;
)
   ...
 }
... when != n
// </smpl>
Signed-off-by: default avatarJulia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1448051604-25256-4-git-send-email-Julia.Lawall@lip6.fr
      7d405a93
    • Julia Lawall's avatar
      powerpc/6xx: add missing of_node_put · f6e82647
      Julia Lawall authored 
      for_each_compatible_node performs an of_node_get on each iteration, so
a break out of the loop requires an of_node_put.

A simplified version of the semantic patch that fixes this problem is as
follows (http://coccinelle.lip6.fr):

// <smpl>
@@
expression e;
local idexpression n;
@@

@@
local idexpression n;
expression e;
@@

 for_each_compatible_node(n,...) {
   ...
(
   of_node_put(n);
|
   e = n
|
+  of_node_put(n);
?  break;
)
   ...
 }
... when != n
// </smpl>
Signed-off-by: default avatarJulia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1448051604-25256-2-git-send-email-Julia.Lawall@lip6.fr
      f6e82647
    • Michael Ellerman's avatar
      Merge branch 'topic/ppc-kvm' into next · ff0d6be4
      Michael Ellerman authored 
      This merge's Nick's big P9 KVM series, original cover letter follows:

KVM: PPC: Book3S HV P9: entry/exit optimisations

This reduces radix guest full entry/exit latency on POWER9 and POWER10
by 2x.

Nested HV guests should see smaller improvements in their L1 entry/exit,
but this is also combined with most L0 speedups also applying to nested
entry. nginx localhost throughput test in a SMP nested guest is improved
about 10% (in a direct guest it doesn't change much because it uses XIVE
for IPIs) when L0 and L1 are patched.

It does this in several main ways:

- Rearrange code to optimise SPR accesses. Mainly, avoid scoreboard
  stalls.

- Test SPR values to avoid mtSPRs where possible. mtSPRs are expensive.

- Reduce mftb. mftb is expensive.

- Demand fault certain facilities to avoid saving and/or restoring them
  (at the cost of fault when they are used, but this is mitigated over
  a number of entries, like the facilities when context switching
  processes). PM, TM, and EBB so far.

- Defer some sequences that are made just in case a guest is interrupted
  in the middle of a critical section to the case where the guest is
  scheduled on a different CPU, rather than every time (at the cost of
  an extra IPI in this case). Namely the tlbsync sequence for radix with
  GTSE, which is very expensive.

- Reduce locking, barriers, atomics related to the vcpus-per-vcore > 1
  handling that the P9 path does not require.
      ff0d6be4
  3. 24 Nov, 2021 36 commits
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