mm/hugetlb: deal with multiple calls to hugetlb_bootmem_alloc

Architectures that want pre-HVO of hugetlb vmemmap pages will need to call
hugetlb_bootmem_alloc from an earlier spot in boot (before sparse_init).
To facilitate some architectures doing this, protect hugetlb_bootmem_alloc
against multiple calls.

Also provide a helper function to check if it's been called, so that the
early HVO code, to be added later, can see if there is anything to do.

Link: https://lkml.kernel.org/r/20250228182928.2645936-16-fvdl@google.com
Signed-off-by: Frank van der Linden <fvdl@google.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin (Cruise) <roman.gushchin@linux.dev>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index a596aaa178d1c06dceacc4e4bf54522ed7d6cefd..f0ab4ca4ecf2a0ca193d17ca528fddb3ec4ad74f 100644 (file)
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -175,6 +175,7 @@ extern int sysctl_hugetlb_shm_group;
 extern struct list_head huge_boot_pages[MAX_NUMNODES];
 
 void hugetlb_bootmem_alloc(void);
+bool hugetlb_bootmem_allocated(void);
 
 /* arch callbacks */
 
@@ -1263,6 +1264,11 @@ static inline bool hugetlbfs_pagecache_present(
 static inline void hugetlb_bootmem_alloc(void)
 {
 }
+
+static inline bool hugetlb_bootmem_allocated(void)
+{
+       return false;
+}
 #endif /* CONFIG_HUGETLB_PAGE */
 
 static inline spinlock_t *huge_pte_lock(struct hstate *h,

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index e4bf06f13178f5036005416525d0ead957bb8b8d..826af96455aa5eab929296d6c93781fd1ea8bbcf 100644 (file)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -4918,16 +4918,28 @@ static int __init default_hugepagesz_setup(char *s)
 }
 hugetlb_early_param("default_hugepagesz", default_hugepagesz_setup);
 
+static bool __hugetlb_bootmem_allocated __initdata;
+
+bool __init hugetlb_bootmem_allocated(void)
+{
+       return __hugetlb_bootmem_allocated;
+}
+
 void __init hugetlb_bootmem_alloc(void)
 {
        struct hstate *h;
 
+       if (__hugetlb_bootmem_allocated)
+               return;
+
        hugetlb_parse_params();
 
        for_each_hstate(h) {
                if (hstate_is_gigantic(h))
                        hugetlb_hstate_alloc_pages(h);
        }
+
+       __hugetlb_bootmem_allocated = true;
 }
 
 static unsigned int allowed_mems_nr(struct hstate *h)