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| author | Paul E. McKenney <paulmck@kernel.org> | 2022-01-31 22:21:30 +0300 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2022-05-03 20:19:39 +0300 |
| commit | a57ffb3c6b67e59e8632f731414b792eacc6cca0 (patch) | |
| tree | 34d09d000fabf5eacfed74c7e5cd23a5959ddb70 /Documentation/admin-guide | |
| parent | 9f2e91d94c91558e3764fe4e01c5e6281a90f239 (diff) | |
| download | linux-a57ffb3c6b67e59e8632f731414b792eacc6cca0.tar.xz | |
srcu: Automatically determine size-transition strategy at boot
This commit adds a srcutree.convert_to_big option of zero that causes
SRCU to decide at boot whether to wait for contention (small systems) or
immediately expand to large (large systems). A new srcutree.big_cpu_lim
(defaulting to 128) defines how many CPUs constitute a large system.
Co-developed-by: Neeraj Upadhyay <quic_neeraju@quicinc.com>
Signed-off-by: Neeraj Upadhyay <quic_neeraju@quicinc.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'Documentation/admin-guide')
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 177e688768c0..0a094bb2d722 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -5608,6 +5608,15 @@ off: Disable mitigation and remove performance impact to RDRAND and RDSEED + srcutree.big_cpu_lim [KNL] + Specifies the number of CPUs constituting a + large system, such that srcu_struct structures + should immediately allocate an srcu_node array. + This kernel-boot parameter defaults to 128, + but takes effect only when the low-order four + bits of srcutree.convert_to_big is equal to 3 + (decide at boot). + srcutree.convert_to_big [KNL] Specifies under what conditions an SRCU tree srcu_struct structure will be converted to big @@ -5616,6 +5625,7 @@ 0: Never. 1: At init_srcu_struct() time. 2: When rcutorture decides to. + 3: Decide at boot time (default). 0x1X: Above plus if high contention. Either way, the srcu_node tree will be sized based |