On Wed, Mar 18, 2026 at 10:33 AM Mike Rapoport wrote: > Hi Michal, > > On Tue, Mar 17, 2026 at 03:15:33PM +0100, Michal Clapinski wrote: > > Currently, if DEFERRED is enabled, kho_release_scratch will initialize > > Please spell out CONFIG_DEFERRED_STRUCT_PAGE_INIT > > > the struct pages and set migratetype of kho scratch. Unless the whole > > scratch fit below first_deferred_pfn, some of that will be overwritten > > either by deferred_init_pages or memmap_init_reserved_pages. > > Usually we put brackets after function names to make them more visible. > > > To fix it, I modified kho_release_scratch to only set the migratetype > > Prefer an imperative mood please, e.g. "To fix it, modify > kho_release_scratch() ..." > > > on already initialized pages. Then, modified init_pageblock_migratetype > > to set the migratetype to CMA if the page is located inside scratch. > > > > Signed-off-by: Michal Clapinski > > --- > > include/linux/memblock.h | 2 -- > > kernel/liveupdate/kexec_handover.c | 10 ++++++---- > > mm/memblock.c | 22 ---------------------- > > mm/page_alloc.c | 7 +++++++ > > 4 files changed, 13 insertions(+), 28 deletions(-) > > > > diff --git a/include/linux/memblock.h b/include/linux/memblock.h > > index 6ec5e9ac0699..3e217414e12d 100644 > > --- a/include/linux/memblock.h > > +++ b/include/linux/memblock.h > > @@ -614,11 +614,9 @@ static inline void memtest_report_meminfo(struct > seq_file *m) { } > > #ifdef CONFIG_MEMBLOCK_KHO_SCRATCH > > void memblock_set_kho_scratch_only(void); > > void memblock_clear_kho_scratch_only(void); > > -void memmap_init_kho_scratch_pages(void); > > #else > > static inline void memblock_set_kho_scratch_only(void) { } > > static inline void memblock_clear_kho_scratch_only(void) { } > > -static inline void memmap_init_kho_scratch_pages(void) {} > > #endif > > > > #endif /* _LINUX_MEMBLOCK_H */ > > diff --git a/kernel/liveupdate/kexec_handover.c > b/kernel/liveupdate/kexec_handover.c > > index c9b982372d6e..e511a50fab9c 100644 > > --- a/kernel/liveupdate/kexec_handover.c > > +++ b/kernel/liveupdate/kexec_handover.c > > @@ -1477,8 +1477,7 @@ static void __init kho_release_scratch(void) > > { > > phys_addr_t start, end; > > u64 i; > > - > > - memmap_init_kho_scratch_pages(); > > + int nid; > > > > /* > > * Mark scratch mem as CMA before we return it. That way we > > @@ -1486,10 +1485,13 @@ static void __init kho_release_scratch(void) > > * we can reuse it as scratch memory again later. > > */ > > __for_each_mem_range(i, &memblock.memory, NULL, NUMA_NO_NODE, > > - MEMBLOCK_KHO_SCRATCH, &start, &end, NULL) { > > + MEMBLOCK_KHO_SCRATCH, &start, &end, &nid) { > > ulong start_pfn = pageblock_start_pfn(PFN_DOWN(start)); > > ulong end_pfn = pageblock_align(PFN_UP(end)); > > ulong pfn; > > +#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT > > + end_pfn = min(end_pfn, NODE_DATA(nid)->first_deferred_pfn); > > +#endif > > A helper that returns first_deferred_pfn or ULONG_MAX might be beeter > looking. > > > > > for (pfn = start_pfn; pfn < end_pfn; pfn += > pageblock_nr_pages) > > init_pageblock_migratetype(pfn_to_page(pfn), > > @@ -1500,8 +1502,8 @@ static void __init kho_release_scratch(void) > > void __init kho_memory_init(void) > > { > > if (kho_in.scratch_phys) { > > - kho_scratch = phys_to_virt(kho_in.scratch_phys); > > kho_release_scratch(); > > + kho_scratch = phys_to_virt(kho_in.scratch_phys); > > Why this change is needed? > It's not necessary but kho_release_scratch() will call kho_scratch_overlap(). If kho_scratch is NULL, kho_scratch_overlap() will return early, making it slightly faster. Alternatively, I skip invoking kho_scratch_overlap() if migratetype is already MIGRATE_CMA. > > > if (kho_mem_retrieve(kho_get_fdt())) > > kho_in.fdt_phys = 0; > > diff --git a/mm/memblock.c b/mm/memblock.c > > index b3ddfdec7a80..ae6a5af46bd7 100644 > > --- a/mm/memblock.c > > +++ b/mm/memblock.c > > @@ -959,28 +959,6 @@ __init void memblock_clear_kho_scratch_only(void) > > { > > kho_scratch_only = false; > > } > > - > > -__init void memmap_init_kho_scratch_pages(void) > > -{ > > - phys_addr_t start, end; > > - unsigned long pfn; > > - int nid; > > - u64 i; > > - > > - if (!IS_ENABLED(CONFIG_DEFERRED_STRUCT_PAGE_INIT)) > > - return; > > - > > - /* > > - * Initialize struct pages for free scratch memory. > > - * The struct pages for reserved scratch memory will be set up in > > - * reserve_bootmem_region() > > - */ > > - __for_each_mem_range(i, &memblock.memory, NULL, NUMA_NO_NODE, > > - MEMBLOCK_KHO_SCRATCH, &start, &end, &nid) { > > - for (pfn = PFN_UP(start); pfn < PFN_DOWN(end); pfn++) > > - init_deferred_page(pfn, nid); > > - } > > -} > > #endif > > > > /** > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > > index ee81f5c67c18..5ca078dde61d 100644 > > --- a/mm/page_alloc.c > > +++ b/mm/page_alloc.c > > @@ -55,6 +55,7 @@ > > #include > > #include > > #include > > +#include > > #include > > #include "internal.h" > > #include "shuffle.h" > > @@ -549,6 +550,12 @@ void __meminit init_pageblock_migratetype(struct > page *page, > > migratetype < MIGRATE_PCPTYPES)) > > migratetype = MIGRATE_UNMOVABLE; > > > > + /* > > + * Mark KHO scratch as CMA so no unmovable allocations are made > there. > > + */ > > + if (unlikely(kho_scratch_overlap(page_to_phys(page), PAGE_SIZE))) > > + migratetype = MIGRATE_CMA; > > + > > Please pick SJ's fixup for the next respin :) > > > flags = migratetype; > > > > #ifdef CONFIG_MEMORY_ISOLATION > > -- > > 2.53.0.851.ga537e3e6e9-goog > > > > -- > Sincerely yours, > Mike. >