On Fri, 29 Sep 2023 12:44:15 +0100 Ryan Roberts <ryan.roberts@xxxxxxx> wrote:
> In preparation for adding support for anonymous large folios that are
> smaller than the PMD-size, introduce 2 new sysfs files that will be used
> to control the new behaviours via the transparent_hugepage interface.
> For now, the kernel still only supports PMD-order anonymous THP, so when
> reading back anon_orders, it will reflect that. Therefore there are no
> behavioural changes intended here.
powerpc strikes again. ARCH=powerpc allmodconfig:
In file included from ./include/linux/bits.h:6,
from ./include/linux/ratelimit_types.h:5,
from ./include/linux/printk.h:9,
from ./include/asm-generic/bug.h:22,
from ./arch/powerpc/include/asm/bug.h:116,
from ./include/linux/bug.h:5,
from ./include/linux/mmdebug.h:5,
from ./include/linux/mm.h:6,
from mm/huge_memory.c:8:
./include/vdso/bits.h:7:33: error: initializer element is not constant
7 | #define BIT(nr) (UL(1) << (nr))
| ^
mm/huge_memory.c:77:47: note: in expansion of macro 'BIT'
77 | unsigned int huge_anon_orders __read_mostly = BIT(PMD_ORDER);
| ^~~
We keep tripping over this. I wish there was a way to fix it.
Style whine: an all-caps identifier is supposed to be a constant,
dammit.
#define PTE_INDEX_SIZE __pte_index_size
Nope.
I did this:
--- a/mm/huge_memory.c~mm-thp-introduce-anon_orders-and-anon_always_mask-sysfs-files-fix
+++ a/mm/huge_memory.c
@@ -74,7 +74,7 @@ static unsigned long deferred_split_scan
static atomic_t huge_zero_refcount;
struct page *huge_zero_page __read_mostly;
unsigned long huge_zero_pfn __read_mostly = ~0UL;
-unsigned int huge_anon_orders __read_mostly = BIT(PMD_ORDER);
+unsigned int huge_anon_orders __read_mostly;
static unsigned int huge_anon_always_mask __read_mostly;
/**
@@ -528,6 +528,9 @@ static int __init hugepage_init_sysfs(st
{
int err;
+ /* powerpc's PMD_ORDER isn't a compile-time constant */
+ huge_anon_orders = BIT(PMD_ORDER);
+
*hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj);
if (unlikely(!*hugepage_kobj)) {
pr_err("failed to create transparent hugepage kobject\n");
_
I assume this is set up early enough.
I don't know why powerpc's PTE_INDEX_SIZE is variable. Hopefully it
has been set up by this time and it won't get altered.
