path: root/Documentation/admin-guide
diff options
authorNicholas Piggin <>2021-05-03 19:17:55 +1000
committerMichael Ellerman <>2021-05-04 11:06:45 +1000
commit8abddd968a303db75e4debe77a3df484164f1f33 (patch)
treeb3ea95c6553f6738df1ca51c25794c701e7f69d0 /Documentation/admin-guide
parent562d1e207d322e6346e8db91bbd11d94f16427d2 (diff)
powerpc/64s/radix: Enable huge vmalloc mappings
This reduces TLB misses by nearly 30x on a `git diff` workload on a 2-node POWER9 (59,800 -> 2,100) and reduces CPU cycles by 0.54%, due to vfs hashes being allocated with 2MB pages. Signed-off-by: Nicholas Piggin <> Reviewed-by: Christophe Leroy <> Acked-by: Michael Ellerman <> Signed-off-by: Michael Ellerman <> Link:
Diffstat (limited to 'Documentation/admin-guide')
1 files changed, 2 insertions, 0 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 02470ba1fe6a..1fcec80b099e 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3251,6 +3251,8 @@
nohugeiomap [KNL,X86,PPC,ARM64] Disable kernel huge I/O mappings.
+ nohugevmalloc [PPC] Disable kernel huge vmalloc mappings.
nosmt [KNL,S390] Disable symmetric multithreading (SMT).
Equivalent to smt=1.