After the page ranges in the pagetable have been reserved the pagetable is no longer needed. Rather than free it during early boot by unreserving page-sized blocks which can be inefficient when dealing with a large number of blocks, wait until the page structs have been initialized and free them as pages.
Signed-off-by: Anthony Yznaga <[email protected]> --- arch/x86/mm/init_64.c | 1 + include/linux/pkram.h | 3 ++ mm/pkram.c | 11 +++++++ mm/pkram_pagetable.c | 82 +++++++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 97 insertions(+) diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index ae569ef6bd7d..72662615977b 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -1245,6 +1245,7 @@ void __init mem_init(void) after_bootmem = 1; x86_init.hyper.init_after_bootmem(); + pkram_free_pgt(); totalram_pages_add(pkram_reserved_pages); /* * Must be done after boot memory is put on freelist, because here we diff --git a/include/linux/pkram.h b/include/linux/pkram.h index 1b475f6e1598..edc5d8bef9d3 100644 --- a/include/linux/pkram.h +++ b/include/linux/pkram.h @@ -39,6 +39,7 @@ struct pkram_pg_state { }; void pkram_walk_pgt_rev(struct pkram_pg_state *st, pgd_t *pgd); +void pkram_free_pgt_walk_pgd(pgd_t *pgd); int pkram_prepare_save(struct pkram_stream *ps, const char *name, gfp_t gfp_mask); @@ -64,9 +65,11 @@ size_t pkram_read(struct pkram_stream *ps, void *buf, size_t count); #ifdef CONFIG_PKRAM extern unsigned long pkram_reserved_pages; void pkram_reserve(void); +void pkram_free_pgt(void); #else #define pkram_reserved_pages 0UL static inline void pkram_reserve(void) { } +static inline void pkram_free_pgt(void) { } #endif #endif /* _LINUX_PKRAM_H */ diff --git a/mm/pkram.c b/mm/pkram.c index 2c323154df76..dd3c89614010 100644 --- a/mm/pkram.c +++ b/mm/pkram.c @@ -1227,3 +1227,14 @@ static int __init pkram_reserve_page_ranges(pgd_t *pgd) return err; } + +void pkram_free_pgt(void) +{ + if (!pkram_pgd) + return; + + pkram_free_pgt_walk_pgd(pkram_pgd); + + __free_pages_core(virt_to_page(pkram_pgd), 0); + pkram_pgd = NULL; +} diff --git a/mm/pkram_pagetable.c b/mm/pkram_pagetable.c index d31aa36207ba..7033e9b1c47f 100644 --- a/mm/pkram_pagetable.c +++ b/mm/pkram_pagetable.c @@ -3,6 +3,8 @@ #include <asm/pgtable.h> #include <linux/pkram.h> +#include "internal.h" + #define pgd_none(a) (pgtable_l5_enabled() ? pgd_none(a) : p4d_none(__p4d(pgd_val(a)))) static int note_page_rev(struct pkram_pg_state *st, unsigned long curr_size, bool present) @@ -167,3 +169,83 @@ void pkram_walk_pgt_rev(struct pkram_pg_state *st, pgd_t *pgd) break; } } + +static void pkram_free_pgt_walk_pmd(pud_t addr) +{ + unsigned long bitmap_pa; + struct page *page; + pmd_t *start; + int i; + + start = (pmd_t *)pud_page_vaddr(addr); + for (i = 0; i < PTRS_PER_PMD; i++, start++) { + if (!pmd_none(*start)) { + bitmap_pa = pte_val(pte_clrhuge(*(pte_t *)start)); + if (pmd_large(*start) && !bitmap_pa) + continue; + page = virt_to_page(__va(bitmap_pa)); + __free_pages_core(page, 0); + } + } +} + +static void pkram_free_pgt_walk_pud(p4d_t addr) +{ + struct page *page; + pud_t *start; + int i; + + start = (pud_t *)p4d_page_vaddr(addr); + for (i = 0; i < PTRS_PER_PUD; i++, start++) { + if (!pud_none(*start)) { + if (pud_large(*start)) { + WARN_ONCE(1, "PKRAM: unexpected pud hugepage\n"); + continue; + } + pkram_free_pgt_walk_pmd(*start); + page = virt_to_page(__va(pud_val(*start))); + __free_pages_core(page, 0); + } + } +} + +static void pkram_free_pgt_walk_p4d(pgd_t addr) +{ + struct page *page; + p4d_t *start; + int i; + + if (PTRS_PER_P4D == 1) + return pkram_free_pgt_walk_pud(__p4d(pgd_val(addr))); + + start = (p4d_t *)pgd_page_vaddr(addr); + for (i = 0; i < PTRS_PER_P4D; i++, start++) { + if (!p4d_none(*start)) { + if (p4d_large(*start)) { + WARN_ONCE(1, "PKRAM: unexpected p4d hugepage\n"); + continue; + } + pkram_free_pgt_walk_pud(*start); + page = virt_to_page(__va(p4d_val(*start))); + __free_pages_core(page, 0); + } + } +} + +/* + * Free the pagetable passed from the previous boot. + */ +void pkram_free_pgt_walk_pgd(pgd_t *pgd) +{ + pgd_t *start = pgd; + struct page *page; + int i; + + for (i = 0; i < PTRS_PER_PGD; i++, start++) { + if (!pgd_none(*start)) { + pkram_free_pgt_walk_p4d(*start); + page = virt_to_page(__va(pgd_val(*start))); + __free_pages_core(page, 0); + } + } +} -- 2.13.3
