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authorAntoine Tenart <atenart@kernel.org>2022-07-07 11:02:45 +0300
committerJakub Kicinski <kuba@kernel.org>2022-07-09 06:15:59 +0300
commit40ad0a52ef5d2c3379bb9b6af06c8029ac6c875d (patch)
treec180ec9f6df06a270fc514bded86b898e188ad8e /Documentation/admin-guide/sysctl
parent5b47d2364652979dc43df14f7af19346a001b770 (diff)
downloadlinux-40ad0a52ef5d2c3379bb9b6af06c8029ac6c875d.tar.xz
Documentation: add a description for net.core.high_order_alloc_disable
A description is missing for the net.core.high_order_alloc_disable option in admin-guide/sysctl/net.rst ; add it. The above sysctl option was introduced by commit ce27ec60648d ("net: add high_order_alloc_disable sysctl/static key"). Thanks to Eric for running again the benchmark cited in the above commit, showing this knob is now mostly of historical importance. Signed-off-by: Antoine Tenart <atenart@kernel.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/r/20220707080245.180525-1-atenart@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'Documentation/admin-guide/sysctl')
-rw-r--r--Documentation/admin-guide/sysctl/net.rst12
1 files changed, 12 insertions, 0 deletions
diff --git a/Documentation/admin-guide/sysctl/net.rst b/Documentation/admin-guide/sysctl/net.rst
index fcd650bdbc7e..805f2281e000 100644
--- a/Documentation/admin-guide/sysctl/net.rst
+++ b/Documentation/admin-guide/sysctl/net.rst
@@ -391,6 +391,18 @@ GRO has decided not to coalesce, it is placed on a per-NAPI list. This
list is then passed to the stack when the number of segments reaches the
gro_normal_batch limit.
+high_order_alloc_disable
+------------------------
+
+By default the allocator for page frags tries to use high order pages (order-3
+on x86). While the default behavior gives good results in most cases, some users
+might have hit a contention in page allocations/freeing. This was especially
+true on older kernels (< 5.14) when high-order pages were not stored on per-cpu
+lists. This allows to opt-in for order-0 allocation instead but is now mostly of
+historical importance.
+
+Default: 0
+
2. /proc/sys/net/unix - Parameters for Unix domain sockets
----------------------------------------------------------