The patch titled
Subject: mm/page_alloc: increase default min_free_kbytes bound
has been added to the -mm tree. Its filename is
mm-page_alloc-increase-default-min_free_kbytes-bound.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-page_alloc-increase-default-min_free_kbytes-bound.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-page_alloc-increase-default-min_free_kbytes-bound.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Joel Savitz <jsavitz@xxxxxxxxxx>
Subject: mm/page_alloc: increase default min_free_kbytes bound
Currently, the vm.min_free_kbytes sysctl value is capped at a hardcoded
64M in init_per_zone_wmark_min (unless it is overridden by khugepaged
initialization).
This value has not been modified since 2005, and enterprise-grade systems
now frequently have hundreds of GB of RAM and multiple 10, 40, or even 100
GB NICs. We have seen page allocation failures on heavily loaded systems
related to NIC drivers. These issues were resolved by an increase to
vm.min_free_kbytes.
This patch increases the hardcoded value by a factor of 4 as a temporary
solution.
Further work to make the calculation of vm.min_free_kbytes more consistent
throughout the kernel would be desirable.
As an example of the inconsistency of the current method, this value is
recalculated by init_per_zone_wmark_min() in the case of memory hotplug
which will override the value set by set_recommended_min_free_kbytes()
called during khugepaged initialization even if khugepaged remains
enabled, however an on/off toggle of khugepaged will then recalculate and
set the value via set_recommended_min_free_kbytes().
Link: http://lkml.kernel.org/r/20200220150103.5183-1-jsavitz@xxxxxxxxxx
Signed-off-by: Joel Savitz <jsavitz@xxxxxxxxxx>
Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Rafael Aquini <aquini@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/mm/page_alloc.c~mm-page_alloc-increase-default-min_free_kbytes-bound
+++ a/mm/page_alloc.c
@@ -7869,8 +7869,8 @@ int __meminit init_per_zone_wmark_min(vo
min_free_kbytes = new_min_free_kbytes;
if (min_free_kbytes < 128)
min_free_kbytes = 128;
- if (min_free_kbytes > 65536)
- min_free_kbytes = 65536;
+ if (min_free_kbytes > 262144)
+ min_free_kbytes = 262144;
} else {
pr_warn("min_free_kbytes is not updated to %d because user defined value %d is preferred\n",
new_min_free_kbytes, user_min_free_kbytes);
_
Patches currently in -mm which might be from jsavitz@xxxxxxxxxx are
mm-page_alloc-increase-default-min_free_kbytes-bound.patch
