Le 28/01/2025 à 00:22, Frank van der Linden a écrit :
If hugetlb_cma_only is enabled, we know that hugetlb pages
can only be allocated from CMA. Now that there is an interface
to do early reservations from a CMA area (returning memblock
memory), it can be used to allocate hugetlb pages from CMA.
This also allows for doing pre-HVO on these pages (if enabled).
Make sure to initialize the page structures and associated data
correctly. Create a flag to signal that a hugetlb page has been
allocated from CMA to make things a little easier.
Some configurations of powerpc have a special hugetlb bootmem
allocator, so introduce a boolean arch_specific_huge_bootmem_alloc
that returns true if such an allocator is present. In that case,
CMA bootmem allocations can't be used, so check that function
before trying.
Cc: Madhavan Srinivasan <ma...@linux.ibm.com>
Cc: Michael Ellerman <m...@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Frank van der Linden <f...@google.com>
---
arch/powerpc/mm/hugetlbpage.c | 5 ++
include/linux/hugetlb.h | 7 ++
mm/hugetlb.c | 135 +++++++++++++++++++++++++---------
3 files changed, 114 insertions(+), 33 deletions(-)
diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index d3c1b749dcfc..e53e4b4c8ef6 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -121,6 +121,11 @@ bool __init hugetlb_node_alloc_supported(void)
{
return false;
}
+
+bool __init arch_specific_huge_bootmem_alloc(struct hstate *h)
+{
+ return (firmware_has_feature(FW_FEATURE_LPAR) && !radix_enabled());
+}
#endif
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 2512463bca49..bca3052fb175 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -591,6 +591,7 @@ enum hugetlb_page_flags {
HPG_freed,
HPG_vmemmap_optimized,
HPG_raw_hwp_unreliable,
+ HPG_cma,
__NR_HPAGEFLAGS,
};
@@ -650,6 +651,7 @@ HPAGEFLAG(Temporary, temporary)
HPAGEFLAG(Freed, freed)
HPAGEFLAG(VmemmapOptimized, vmemmap_optimized)
HPAGEFLAG(RawHwpUnreliable, raw_hwp_unreliable)
+HPAGEFLAG(Cma, cma)
#ifdef CONFIG_HUGETLB_PAGE
@@ -678,14 +680,18 @@ struct hstate {
char name[HSTATE_NAME_LEN];
};
+struct cma;
+
struct huge_bootmem_page {
struct list_head list;
struct hstate *hstate;
unsigned long flags;
+ struct cma *cma;
};
#define HUGE_BOOTMEM_HVO 0x0001
#define HUGE_BOOTMEM_ZONES_VALID 0x0002
+#define HUGE_BOOTMEM_CMA 0x0004
bool hugetlb_bootmem_page_zones_valid(int nid, struct huge_bootmem_page *m);
@@ -711,6 +717,7 @@ bool __init hugetlb_node_alloc_supported(void);
void __init hugetlb_add_hstate(unsigned order);
bool __init arch_hugetlb_valid_size(unsigned long size);
+bool __init arch_specific_huge_bootmem_alloc(struct hstate *h);
Why adding 'specific' in the name ? Prefixing a function name with arch_
is usually enough to denote an architecture specific function.
struct hstate *size_to_hstate(unsigned long size);
#ifndef HUGE_MAX_HSTATE
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 32ebde9039e2..183e8d0c2fb4 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -61,7 +61,7 @@ static struct cma *hugetlb_cma[MAX_NUMNODES];
static unsigned long hugetlb_cma_size_in_node[MAX_NUMNODES] __initdata;
#endif
static bool hugetlb_cma_only;
-static unsigned long hugetlb_cma_size __initdata;
+static unsigned long hugetlb_cma_size;
Why remove __initdata ? As far as I can see it is used only in
hugetlb_early_cma() and hugetlb_hstate_alloc_pages() which are __init
functions.
__initdata struct list_head huge_boot_pages[MAX_NUMNODES];
__initdata unsigned long hstate_boot_nrinvalid[HUGE_MAX_HSTATE];
@@ -132,8 +132,10 @@ static void hugetlb_free_folio(struct folio *folio)
#ifdef CONFIG_CMA
int nid = folio_nid(folio);
- if (cma_free_folio(hugetlb_cma[nid], folio))
+ if (folio_test_hugetlb_cma(folio)) {
+ WARN_ON(!cma_free_folio(hugetlb_cma[nid], folio));
Is that WARN_ON() needed ? See
https://docs.kernel.org/process/coding-style.html#do-not-crash-the-kernel
return;
+ }
#endif
folio_put(folio);
}
@@ -1509,6 +1511,9 @@ static struct folio *alloc_gigantic_folio(struct hstate
*h, gfp_t gfp_mask,
break;
}
}
+
+ if (folio)
+ folio_set_hugetlb_cma(folio);
}
#endif
if (!folio) {
@@ -3175,6 +3180,63 @@ struct folio *alloc_hugetlb_folio(struct vm_area_struct
*vma,
return ERR_PTR(-ENOSPC);
}
+/*
+ * Some architectures do their own bootmem allocation, so they can't use
+ * early CMA allocation. So, allow for this function to be redefined.
+ */
+bool __init __attribute((weak))
Can't you use __weak ?
By the way, do we really need a weak function here ? Can't it be a
static inline helper that gets waived by a macro defined by the arch,
something like:
#ifndef arch_huge_bootmem_alloc
static inline arch_huge_bootmem_alloc(struct hstate *h)
{
return false;
}
#endif
Then powerpc does:
#define arch_huge_bootmem_alloc arch_huge_bootmem_alloc
static inline arch_huge_bootmem_alloc(struct hstate *h)
{
return (firmware_has_feature(FW_FEATURE_LPAR) && !radix_enabled());
}
But why is struct hstate *h parameter needed ? Seems like noone uses it.
+arch_specific_huge_bootmem_alloc(struct hstate *h)
+{
+ return false;
+}
+
+static bool __init hugetlb_early_cma(struct hstate *h)
+{
+ if (arch_specific_huge_bootmem_alloc(h))
+ return false;
+
+ return (hstate_is_gigantic(h) && hugetlb_cma_size && hugetlb_cma_only);
+}
+
+static __init void *alloc_bootmem(struct hstate *h, int nid)
+{
+ struct huge_bootmem_page *m;
+ unsigned long flags;
+ struct cma *cma;
+
+#ifdef CONFIG_CMA
#ifdefs in C files should be avoided, see
https://docs.kernel.org/process/coding-style.html#conditional-compilation
+ if (hugetlb_early_cma(h)) {
+ flags = HUGE_BOOTMEM_CMA;
+ cma = hugetlb_cma[nid];
+ m = cma_reserve_early(cma, huge_page_size(h));
+ } else
+#endif
This kind of if/else construct in uggly, should be avoided.
+ {
+ flags = 0;
+ cma = NULL;
+ m = memblock_alloc_try_nid_raw(huge_page_size(h),
+ huge_page_size(h), 0, MEMBLOCK_ALLOC_ACCESSIBLE, nid);
+ }
+
+ if (m) {
+ /*
+ * Use the beginning of the huge page to store the
+ * huge_bootmem_page struct (until gather_bootmem
+ * puts them into the mem_map).
+ *
+ * Put them into a private list first because mem_map
+ * is not up yet.
+ */
+ INIT_LIST_HEAD(&m->list);
+ list_add(&m->list, &huge_boot_pages[nid]);
+ m->hstate = h;
+ m->flags = flags;
+ m->cma = cma;
+ }
+
+ return m;
+}
+
int alloc_bootmem_huge_page(struct hstate *h, int nid)
__attribute__ ((weak, alias("__alloc_bootmem_huge_page")));
int __alloc_bootmem_huge_page(struct hstate *h, int nid)
@@ -3184,17 +3246,14 @@ int __alloc_bootmem_huge_page(struct hstate *h, int nid)
/* do node specific alloc */
if (nid != NUMA_NO_NODE) {
- m = memblock_alloc_try_nid_raw(huge_page_size(h),
huge_page_size(h),
- 0, MEMBLOCK_ALLOC_ACCESSIBLE, nid);
+ m = alloc_bootmem(h, node);
if (!m)
return 0;
goto found;
}
/* allocate from next node when distributing huge pages */
for_each_node_mask_to_alloc(&h->next_nid_to_alloc, nr_nodes, node,
&node_states[N_ONLINE]) {
- m = memblock_alloc_try_nid_raw(
- huge_page_size(h), huge_page_size(h),
- 0, MEMBLOCK_ALLOC_ACCESSIBLE, node);
+ m = alloc_bootmem(h, node);
if (m)
break;
}
@@ -3203,7 +3262,6 @@ int __alloc_bootmem_huge_page(struct hstate *h, int nid)
return 0;
found:
-
/*
* Only initialize the head struct page in memmap_init_reserved_pages,
* rest of the struct pages will be initialized by the HugeTLB
@@ -3213,18 +3271,6 @@ int __alloc_bootmem_huge_page(struct hstate *h, int nid)
*/
memblock_reserved_mark_noinit(virt_to_phys((void *)m + PAGE_SIZE),
huge_page_size(h) - PAGE_SIZE);
- /*
- * Use the beginning of the huge page to store the
- * huge_bootmem_page struct (until gather_bootmem
- * puts them into the mem_map).
- *
- * Put them into a private list first because mem_map
- * is not up yet.
- */
- INIT_LIST_HEAD(&m->list);
- list_add(&m->list, &huge_boot_pages[node]);
- m->hstate = h;
- m->flags = 0;
return 1;
}
@@ -3265,13 +3311,25 @@ static void __init hugetlb_folio_init_vmemmap(struct folio *folio,
prep_compound_head((struct page *)folio, huge_page_order(h));
}
+static bool __init hugetlb_bootmem_page_prehvo(struct huge_bootmem_page *m)
+{
+ return (m->flags & HUGE_BOOTMEM_HVO);
Parenthesis are superflous
+}
+
+static bool __init hugetlb_bootmem_page_earlycma(struct huge_bootmem_page *m)
+{
+ return (m->flags & HUGE_BOOTMEM_CMA);
Parenthesis are superflous
+}
+
/*
* memblock-allocated pageblocks might not have the migrate type set
* if marked with the 'noinit' flag. Set it to the default (MIGRATE_MOVABLE)
- * here.
+ * here, or MIGRATE_CMA if this was a page allocated through an early CMA
+ * reservation.
*
- * Note that this will not write the page struct, it is ok (and necessary)
- * to do this on vmemmap optimized folios.
+ * In case of vmemmap optimized folios, the tail vmemmap pages are mapped
+ * read-only, but that's ok - for sparse vmemmap this does not write to
+ * the page structure.
*/
static void __init hugetlb_bootmem_init_migratetype(struct folio *folio,
struct hstate *h)
@@ -3280,9 +3338,13 @@ static void __init
hugetlb_bootmem_init_migratetype(struct folio *folio,
WARN_ON_ONCE(!pageblock_aligned(folio_pfn(folio)));
- for (i = 0; i < nr_pages; i += pageblock_nr_pages)
- set_pageblock_migratetype(folio_page(folio, i),
+ for (i = 0; i < nr_pages; i += pageblock_nr_pages) {
+ if (folio_test_hugetlb_cma(folio))
+ init_cma_pageblock(folio_page(folio, i));
+ else
+ set_pageblock_migratetype(folio_page(folio, i),
MIGRATE_MOVABLE);
+ }
}
static void __init prep_and_add_bootmem_folios(struct hstate *h,
@@ -3319,7 +3381,7 @@ bool __init hugetlb_bootmem_page_zones_valid(int nid,
struct huge_bootmem_page *m)
{
unsigned long start_pfn;
- bool valid;
+ bool valid = false;
Why do you need that, I can't see any path to reach out: without setting
'valid'.
if (m->flags & HUGE_BOOTMEM_ZONES_VALID) {
/*
@@ -3328,10 +3390,16 @@ bool __init hugetlb_bootmem_page_zones_valid(int nid,
return true;
}
+ if (hugetlb_bootmem_page_earlycma(m)) {
+ valid = cma_validate_zones(m->cma);
+ goto out;
+ }
+
start_pfn = virt_to_phys(m) >> PAGE_SHIFT;
valid = !pfn_range_intersects_zones(nid, start_pfn,
pages_per_huge_page(m->hstate));
+out:
if (!valid)
hstate_boot_nrinvalid[hstate_index(m->hstate)]++;
@@ -3360,11 +3428,6 @@ static void __init hugetlb_bootmem_free_invalid_page(int nid, struct page *page,
}
}
-static bool __init hugetlb_bootmem_page_prehvo(struct huge_bootmem_page *m)
-{
- return (m->flags & HUGE_BOOTMEM_HVO);
-}
-
/*
* Put bootmem huge pages into the standard lists after mem_map is up.
* Note: This only applies to gigantic (order > MAX_PAGE_ORDER) pages.
@@ -3414,6 +3477,9 @@ static void __init gather_bootmem_prealloc_node(unsigned
long nid)
*/
folio_set_hugetlb_vmemmap_optimized(folio);
+ if (hugetlb_bootmem_page_earlycma(m))
+ folio_set_hugetlb_cma(folio);
+
list_add(&folio->lru, &folio_list);
/*
@@ -3606,8 +3672,11 @@ static void __init hugetlb_hstate_alloc_pages(struct
hstate *h)
{
unsigned long allocated;
- /* skip gigantic hugepages allocation if hugetlb_cma enabled */
- if (hstate_is_gigantic(h) && hugetlb_cma_size) {
+ /*
+ * Skip gigantic hugepages allocation if early CMA
+ * reservations are not available.
+ */
+ if (hstate_is_gigantic(h) && hugetlb_cma_size && !hugetlb_early_cma(h))
{
pr_warn_once("HugeTLB: hugetlb_cma is enabled, skip boot time
allocation\n");
return;
}
