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mm: cma: set early_pfn and bitmap as a union in cma_memrange

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Since early_pfn and bitmap are never used at the same time, they can be
defined as a union to reduce the size of the data structure.  This change
can save 8 * u64 entries per CMA.

Link: https://lkml.kernel.org/r/20250509083528.1360952-1-hezhongkun.hzk@bytedance.com
Signed-off-by: Zhongkun He <hezhongkun.hzk@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Zhongkun He 2025-05-09 16:35:28 +08:00 • committed by Andrew Morton
parent 2616b37032
commit 83b6d498d0
2 changed files with 10 additions and 7 deletions
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11
mm/cma.c
View file

@ -143,13 +143,14 @@ bool cma_validate_zones(struct cma *cma)
static void __init cma_activate_area(struct cma *cma)
{
unsigned long pfn, end_pfn;
unsigned long pfn, end_pfn, early_pfn[CMA_MAX_RANGES];
int allocrange, r;
struct cma_memrange *cmr;
unsigned long bitmap_count, count;
for (allocrange = 0; allocrange < cma->nranges; allocrange++) {
cmr = &cma->ranges[allocrange];
early_pfn[allocrange] = cmr->early_pfn;
cmr->bitmap = bitmap_zalloc(cma_bitmap_maxno(cma, cmr),
GFP_KERNEL);
if (!cmr->bitmap)
@ -161,13 +162,13 @@ static void __init cma_activate_area(struct cma *cma)
for (r = 0; r < cma->nranges; r++) {
cmr = &cma->ranges[r];
if (cmr->early_pfn != cmr->base_pfn) {
count = cmr->early_pfn - cmr->base_pfn;
if (early_pfn[r] != cmr->base_pfn) {
count = early_pfn[r] - cmr->base_pfn;
bitmap_count = cma_bitmap_pages_to_bits(cma, count);
bitmap_set(cmr->bitmap, 0, bitmap_count);
}
for (pfn = cmr->early_pfn; pfn < cmr->base_pfn + cmr->count;
for (pfn = early_pfn[r]; pfn < cmr->base_pfn + cmr->count;
pfn += pageblock_nr_pages)
init_cma_reserved_pageblock(pfn_to_page(pfn));
}
@ -193,7 +194,7 @@ cleanup:
for (r = 0; r < allocrange; r++) {
cmr = &cma->ranges[r];
end_pfn = cmr->base_pfn + cmr->count;
for (pfn = cmr->early_pfn; pfn < end_pfn; pfn++)
for (pfn = early_pfn[r]; pfn < end_pfn; pfn++)
free_reserved_page(pfn_to_page(pfn));
}
}

6
mm/cma.h
View file

@ -25,9 +25,11 @@ struct cma_kobject {
*/
struct cma_memrange {
unsigned long base_pfn;
unsigned long early_pfn;
unsigned long count;
unsigned long *bitmap;
union {
unsigned long early_pfn;
unsigned long *bitmap;
};
#ifdef CONFIG_CMA_DEBUGFS
struct debugfs_u32_array dfs_bitmap;
#endif