Messages in this thread Patch in this message | | | From | jglisse@redhat ... | Subject | [PATCH] x86/mm/hotplug: fix BUG_ON() after hotremove by not freeing pud v3 | Date | Sat, 24 Jun 2017 14:05:14 -0400 |
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From: Jérôme Glisse <jglisse@redhat.com>
With commit af2cf278ef4f we no longer free pud so that we do not have synchronize all pgd on hotremove/vfree. But the new 5 level page table patchset reverted that for 4 level page table.
This patch restore af2cf278ef4f and disable free_pud() if we are in the 4 level page table case thus avoiding BUG_ON() after hot- remove.
af2cf278ef4f x86/mm/hotplug: Don't remove PGD entries in remove_pagetable()
Changed since v2: - nove to if the callsite instead of having special version of free_pud for 4 level page table Changed since v1: - make free_pud() conditional on the number of page table level - improved commit message
Signed-off-by: Jérôme Glisse <jglisse@redhat.com> Reviwed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: Andrew Morton <akpm@linux-foundation.org> --- arch/x86/mm/init_64.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 95651dc58e09..dc4c99f9ca58 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -990,7 +990,13 @@ remove_p4d_table(p4d_t *p4d_start, unsigned long addr, unsigned long end, pud_base = pud_offset(p4d, 0); remove_pud_table(pud_base, addr, next, direct); - free_pud_table(pud_base, p4d); + /* + * For 4 levels page table we do not want to free puds but for + * 5 levels we should free them. This code also need to change + * to adapt for boot time switching between 4 and 5 level. + */ + if (CONFIG_PGTABLE_LEVELS == 5) + free_pud_table(pud_base, p4d); } if (direct) -- 2.13.0
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