From 40ad0a52ef5d2c3379bb9b6af06c8029ac6c875d Mon Sep 17 00:00:00 2001 From: Antoine Tenart Date: Thu, 7 Jul 2022 10:02:45 +0200 Subject: [PATCH] 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 Reviewed-by: Eric Dumazet Link: https://lore.kernel.org/r/20220707080245.180525-1-atenart@kernel.org Signed-off-by: Jakub Kicinski --- Documentation/admin-guide/sysctl/net.rst | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/Documentation/admin-guide/sysctl/net.rst b/Documentation/admin-guide/sysctl/net.rst index fcd650b..805f228 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 ---------------------------------------------------------- -- 2.7.4