mm/hugetlb_cma: support percentage-based hugetlb_cma reservation

Browse source

Currently, hugetlb_cma reservation only supports absolute sizes (e.g.,
hugetlb_cma=2G or hugetlb_cma=0:1G,1:1G).  This can be restrictive in
heterogeneous environments or when deploying common kernel command lines
across machines with different memory capacities.

Add support for percentage-based hugetlb_cma reservation (e.g.,
hugetlb_cma=20% or hugetlb_cma=0:20%,1:10%).

The percentage is calculated against the total memory (for global
settings) or against the node-specific memory (for node-specific settings)
using memblock APIs during early boot.

Link: https://lore.kernel.org/20260807040003.2156630-1-souravpanda@google.com
Signed-off-by: Sourav Panda <souravpanda@google.com>
Acked-by: Usama Arif <usama.arif@linux.dev>
Cc: David Hildenbrand <david@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Frank van der Linden <fvdl@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

...

This commit is contained in:

Sourav Panda 2026-08-07 04:00:03 +00:00 • committed by Andrew Morton

parent 28b13c3c4c

commit 34e0849142

2 changed files with 142 additions and 10 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

10

Documentation/admin-guide/kernel-parameters.txt

View file

142

mm/hugetlb_cma.c

View file