[PATCH v4 9/9] mm/page_alloc: allow base for movablecore

From: Doug Berger
Date: Fri Mar 10 2023 - 19:41:15 EST


A Designated Movable Block can be created by including the base
address of the block when specifying a movablecore range on the
kernel command line.

Signed-off-by: Doug Berger <opendmb@xxxxxxxxx>
---
.../admin-guide/kernel-parameters.txt | 14 ++++++-
mm/page_alloc.c | 38 ++++++++++++++++---
2 files changed, 45 insertions(+), 7 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 6221a1d057dd..5e3bf6e0a264 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3353,7 +3353,7 @@
reporting absolute coordinates, such as tablets

movablecore= [KNL,X86,IA-64,PPC]
- Format: nn[KMGTPE] | nn%
+ Format: nn[KMGTPE] | nn[KMGTPE]@ss[KMGTPE] | nn%
This parameter is the complement to kernelcore=, it
specifies the amount of memory used for migratable
allocations. If both kernelcore and movablecore is
@@ -3363,6 +3363,18 @@
that the amount of memory usable for all allocations
is not too small.

+ If @ss[KMGTPE] is included, memory within the region
+ from ss to ss+nn will be designated as a movable block
+ and included in ZONE_MOVABLE. Designated Movable Blocks
+ must be aligned to pageblock_order. Designated Movable
+ Blocks take priority over values of kernelcore= and are
+ considered part of any memory specified by more general
+ movablecore= values.
+ Multiple Designated Movable Blocks may be specified,
+ comma delimited.
+ Example:
+ movablecore=100M@2G,100M@3G,1G@1024G
+
movable_node [KNL] Boot-time switch to make hotplugable memory
NUMA nodes to be movable. This means that the memory
of such nodes will be usable only for movable
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index d4358d19d5a1..cb3c55acf7de 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -8504,9 +8504,9 @@ void __init free_area_init(unsigned long *max_zone_pfn)
}

static int __init cmdline_parse_core(char *p, unsigned long *core,
- unsigned long *percent)
+ unsigned long *percent, bool movable)
{
- unsigned long long coremem;
+ unsigned long long coremem, address;
char *endptr;

if (!p)
@@ -8521,6 +8521,17 @@ static int __init cmdline_parse_core(char *p, unsigned long *core,
*percent = coremem;
} else {
coremem = memparse(p, &p);
+ if (movable && *p == '@') {
+ address = memparse(++p, &p);
+ if (*p != '\0' ||
+ !memblock_is_region_memory(address, coremem) ||
+ memblock_is_region_reserved(address, coremem))
+ return -EINVAL;
+ memblock_reserve(address, coremem);
+ return dmb_reserve(address, coremem, NULL);
+ } else if (*p != '\0') {
+ return -EINVAL;
+ }
/* Paranoid check that UL is enough for the coremem value */
WARN_ON((coremem >> PAGE_SHIFT) > ULONG_MAX);

@@ -8543,17 +8554,32 @@ static int __init cmdline_parse_kernelcore(char *p)
}

return cmdline_parse_core(p, &required_kernelcore,
- &required_kernelcore_percent);
+ &required_kernelcore_percent, false);
}

/*
* movablecore=size sets the amount of memory for use for allocations that
- * can be reclaimed or migrated.
+ * can be reclaimed or migrated. movablecore=size@base defines a Designated
+ * Movable Block.
*/
static int __init cmdline_parse_movablecore(char *p)
{
- return cmdline_parse_core(p, &required_movablecore,
- &required_movablecore_percent);
+ int ret = -EINVAL;
+
+ while (p) {
+ char *k = strchr(p, ',');
+
+ if (k)
+ *k++ = 0;
+
+ ret = cmdline_parse_core(p, &required_movablecore,
+ &required_movablecore_percent, true);
+ if (ret)
+ break;
+ p = k;
+ }
+
+ return ret;
}

early_param("kernelcore", cmdline_parse_kernelcore);
--
2.34.1