Function init_reserved_page() is introduced in commit 7e18adb4f80b ("mm:
meminit: initialize remaining struct pages in parallel with kswapd").
While I am confused why it uses for_each_mem_pfn_range() in
deferred_init_memmap() to initialize deferred pages structure.
After commit 2f47a91f4dab ("mm: deferred_init_memmap improvements"),
deferred_init_memmap() uses for_each_free_mem_range() to initialize
page structure. This means the reserved memory is not touched.
The original context before commit 7e18adb4f80b ("mm: meminit: initialize
remaining struct pages in parallel with kswapd"), reserved memory's page
structure is just SetPageReserved, which means they are not necessary to be
initialized.
This patch removes init_reserved_page() to restore the original context.
Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx>
---
I did bootup and kernel build test with the patched kernel, it looks good.
One of my confusion is the commit 7e18adb4f80b ("mm: meminit: initialize
remaining struct pages in parallel with kswapd") works fine. Does it eat some
reserved pages? Either I don't see the reason in commit 2f47a91f4dab ("mm:
deferred_init_memmap improvements") of changing pfn iteration from
for_each_mem_pfn_range() to for_each_free_mem_range().
Another question is in function reserve_bootmem_region(), we add a
INIT_LIST_HEAD() in commit 1d798ca3f164 ("mm: make compound_head() robust").
While the reserved page is never visible in page allocator. Do we still need
to do this step?
---
mm/page_alloc.c | 28 ----------------------------
1 file changed, 28 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 2d3c54201255..48cf24766343 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1192,32 +1192,6 @@ static void __meminit __init_single_page(struct page *page, unsigned long pfn,
#endif
}
-#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
-static void __meminit init_reserved_page(unsigned long pfn)
-{
- pg_data_t *pgdat;
- int nid, zid;
-
- if (!early_page_uninitialised(pfn))
- return;
-
- nid = early_pfn_to_nid(pfn);
- pgdat = NODE_DATA(nid);
-
- for (zid = 0; zid < MAX_NR_ZONES; zid++) {
- struct zone *zone = &pgdat->node_zones[zid];
-
- if (pfn >= zone->zone_start_pfn && pfn < zone_end_pfn(zone))
- break;
- }
- __init_single_page(pfn_to_page(pfn), pfn, zid, nid);
-}
-#else
-static inline void init_reserved_page(unsigned long pfn)
-{
-}
-#endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */
-
/*
* Initialised pages do not have PageReserved set. This function is
* called for each range allocated by the bootmem allocator and
@@ -1233,8 +1207,6 @@ void __meminit reserve_bootmem_region(phys_addr_t start, phys_addr_t end)
if (pfn_valid(start_pfn)) {
struct page *page = pfn_to_page(start_pfn);
- init_reserved_page(start_pfn);
-
/* Avoid false-positive PageTail() */
INIT_LIST_HEAD(&page->lru);
--
2.15.1
