From: jglisse@redhat.com
To: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org,
"Jérôme Glisse" <jglisse@redhat.com>,
"Andy Lutomirski" <luto@kernel.org>,
"Ingo Molnar" <mingo@kernel.org>,
"Logan Gunthorpe" <logang@deltatee.com>,
"Andrew Morton" <akpm@linux-foundation.org>
Subject: [PATCH] x86/mm/hotplug: fix BUG_ON() after hotremove by not freeing pud v3
Date: Sat, 24 Jun 2017 14:05:14 -0400 [thread overview]
Message-ID: <20170624180514.3821-1-jglisse@redhat.com> (raw)
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
next reply other threads:[~2017-06-24 18:05 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-24 18:05 jglisse [this message]
2017-06-26 9:43 ` [PATCH] x86/mm/hotplug: fix BUG_ON() after hotremove by not freeing pud v3 Ingo Molnar
2017-06-26 14:49 ` Jerome Glisse
2017-06-27 7:19 ` [tip:x86/urgent] x86/mm/hotplug: Fix BUG_ON() after hot-remove by not freeing PUD tip-bot for Jérôme Glisse
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