* [PATCH] x86/mm/hotplug: fix BUG_ON() after hotremove
@ 2017-06-06 17:35 ` Jérôme Glisse
0 siblings, 0 replies; 8+ messages in thread
From: Jérôme Glisse @ 2017-06-06 17:35 UTC (permalink / raw)
To: linux-kernel, linux-mm
Cc: Jérôme Glisse, Andy Lutomirski, Ingo Molnar,
Kirill A . Shutemov, Logan Gunthorpe
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 code re-added that code f2a6a705 and
thus we now trigger a BUG_ON() l128 in sync_global_pgds()
This patch remove free_pud() like in af2cf278ef4f
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
---
arch/x86/mm/init_64.c | 19 -------------------
1 file changed, 19 deletions(-)
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index a8a9972..8cf7e99 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -772,24 +772,6 @@ static void __meminit free_pmd_table(pmd_t *pmd_start, pud_t *pud)
spin_unlock(&init_mm.page_table_lock);
}
-static void __meminit free_pud_table(pud_t *pud_start, p4d_t *p4d)
-{
- pud_t *pud;
- int i;
-
- for (i = 0; i < PTRS_PER_PUD; i++) {
- pud = pud_start + i;
- if (!pud_none(*pud))
- return;
- }
-
- /* free a pud talbe */
- free_pagetable(p4d_page(*p4d), 0);
- spin_lock(&init_mm.page_table_lock);
- p4d_clear(p4d);
- spin_unlock(&init_mm.page_table_lock);
-}
-
static void __meminit
remove_pte_table(pte_t *pte_start, unsigned long addr, unsigned long end,
bool direct)
@@ -991,7 +973,6 @@ 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);
}
if (direct)
--
2.9.3
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH] x86/mm/hotplug: fix BUG_ON() after hotremove
@ 2017-06-06 17:35 ` Jérôme Glisse
0 siblings, 0 replies; 8+ messages in thread
From: Jérôme Glisse @ 2017-06-06 17:35 UTC (permalink / raw)
To: linux-kernel, linux-mm
Cc: Jérôme Glisse, Andy Lutomirski, Ingo Molnar,
Kirill A . Shutemov, Logan Gunthorpe
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 code re-added that code f2a6a705 and
thus we now trigger a BUG_ON() l128 in sync_global_pgds()
This patch remove free_pud() like in af2cf278ef4f
Signed-off-by: JA(C)rA'me Glisse <jglisse@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
---
arch/x86/mm/init_64.c | 19 -------------------
1 file changed, 19 deletions(-)
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index a8a9972..8cf7e99 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -772,24 +772,6 @@ static void __meminit free_pmd_table(pmd_t *pmd_start, pud_t *pud)
spin_unlock(&init_mm.page_table_lock);
}
-static void __meminit free_pud_table(pud_t *pud_start, p4d_t *p4d)
-{
- pud_t *pud;
- int i;
-
- for (i = 0; i < PTRS_PER_PUD; i++) {
- pud = pud_start + i;
- if (!pud_none(*pud))
- return;
- }
-
- /* free a pud talbe */
- free_pagetable(p4d_page(*p4d), 0);
- spin_lock(&init_mm.page_table_lock);
- p4d_clear(p4d);
- spin_unlock(&init_mm.page_table_lock);
-}
-
static void __meminit
remove_pte_table(pte_t *pte_start, unsigned long addr, unsigned long end,
bool direct)
@@ -991,7 +973,6 @@ 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);
}
if (direct)
--
2.9.3
--
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^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH] x86/mm/hotplug: fix BUG_ON() after hotremove
2017-06-06 17:35 ` Jérôme Glisse
@ 2017-06-06 19:50 ` Logan Gunthorpe
-1 siblings, 0 replies; 8+ messages in thread
From: Logan Gunthorpe @ 2017-06-06 19:50 UTC (permalink / raw)
To: Jérôme Glisse, linux-kernel, linux-mm
Cc: Andy Lutomirski, Ingo Molnar, Kirill A . Shutemov
Thanks Jerome! This indeed fixes the bug I reported.
Tested-by: Logan Gunthorpe <logang@deltatee.com>
Logan
On 06/06/17 11:35 AM, Jérôme Glisse wrote:
> 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 code re-added that code f2a6a705 and
> thus we now trigger a BUG_ON() l128 in sync_global_pgds()
>
> This patch remove free_pud() like in af2cf278ef4f
>
> Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
> Cc: Andy Lutomirski <luto@kernel.org>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Cc: Logan Gunthorpe <logang@deltatee.com>
> ---
> arch/x86/mm/init_64.c | 19 -------------------
> 1 file changed, 19 deletions(-)
>
> diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
> index a8a9972..8cf7e99 100644
> --- a/arch/x86/mm/init_64.c
> +++ b/arch/x86/mm/init_64.c
> @@ -772,24 +772,6 @@ static void __meminit free_pmd_table(pmd_t *pmd_start, pud_t *pud)
> spin_unlock(&init_mm.page_table_lock);
> }
>
> -static void __meminit free_pud_table(pud_t *pud_start, p4d_t *p4d)
> -{
> - pud_t *pud;
> - int i;
> -
> - for (i = 0; i < PTRS_PER_PUD; i++) {
> - pud = pud_start + i;
> - if (!pud_none(*pud))
> - return;
> - }
> -
> - /* free a pud talbe */
> - free_pagetable(p4d_page(*p4d), 0);
> - spin_lock(&init_mm.page_table_lock);
> - p4d_clear(p4d);
> - spin_unlock(&init_mm.page_table_lock);
> -}
> -
> static void __meminit
> remove_pte_table(pte_t *pte_start, unsigned long addr, unsigned long end,
> bool direct)
> @@ -991,7 +973,6 @@ 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);
> }
>
> if (direct)
>
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] x86/mm/hotplug: fix BUG_ON() after hotremove
@ 2017-06-06 19:50 ` Logan Gunthorpe
0 siblings, 0 replies; 8+ messages in thread
From: Logan Gunthorpe @ 2017-06-06 19:50 UTC (permalink / raw)
To: Jérôme Glisse, linux-kernel, linux-mm
Cc: Andy Lutomirski, Ingo Molnar, Kirill A . Shutemov
Thanks Jerome! This indeed fixes the bug I reported.
Tested-by: Logan Gunthorpe <logang@deltatee.com>
Logan
On 06/06/17 11:35 AM, JA(C)rA'me Glisse wrote:
> 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 code re-added that code f2a6a705 and
> thus we now trigger a BUG_ON() l128 in sync_global_pgds()
>
> This patch remove free_pud() like in af2cf278ef4f
>
> Signed-off-by: JA(C)rA'me Glisse <jglisse@redhat.com>
> Cc: Andy Lutomirski <luto@kernel.org>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Cc: Logan Gunthorpe <logang@deltatee.com>
> ---
> arch/x86/mm/init_64.c | 19 -------------------
> 1 file changed, 19 deletions(-)
>
> diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
> index a8a9972..8cf7e99 100644
> --- a/arch/x86/mm/init_64.c
> +++ b/arch/x86/mm/init_64.c
> @@ -772,24 +772,6 @@ static void __meminit free_pmd_table(pmd_t *pmd_start, pud_t *pud)
> spin_unlock(&init_mm.page_table_lock);
> }
>
> -static void __meminit free_pud_table(pud_t *pud_start, p4d_t *p4d)
> -{
> - pud_t *pud;
> - int i;
> -
> - for (i = 0; i < PTRS_PER_PUD; i++) {
> - pud = pud_start + i;
> - if (!pud_none(*pud))
> - return;
> - }
> -
> - /* free a pud talbe */
> - free_pagetable(p4d_page(*p4d), 0);
> - spin_lock(&init_mm.page_table_lock);
> - p4d_clear(p4d);
> - spin_unlock(&init_mm.page_table_lock);
> -}
> -
> static void __meminit
> remove_pte_table(pte_t *pte_start, unsigned long addr, unsigned long end,
> bool direct)
> @@ -991,7 +973,6 @@ 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);
> }
>
> if (direct)
>
--
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^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] x86/mm/hotplug: fix BUG_ON() after hotremove
2017-06-06 17:35 ` Jérôme Glisse
@ 2017-06-07 10:47 ` Kirill A. Shutemov
-1 siblings, 0 replies; 8+ messages in thread
From: Kirill A. Shutemov @ 2017-06-07 10:47 UTC (permalink / raw)
To: Jérôme Glisse
Cc: linux-kernel, linux-mm, Andy Lutomirski, Ingo Molnar,
Kirill A . Shutemov, Logan Gunthorpe
On Tue, Jun 06, 2017 at 01:35:12PM -0400, Jérôme Glisse wrote:
> 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 code re-added that code f2a6a705 and
> thus we now trigger a BUG_ON() l128 in sync_global_pgds()
>
> This patch remove free_pud() like in af2cf278ef4f
Good catch. Thanks!
But I think we only need to skip free_pud_table() for 4-level paging.
If we don't we would leave 513 page tables around instead of one in
5-level paging case.
I don't think it's acceptable.
And please use patch subject lines along with commit hashes to simplify
reading commit message.
--
Kirill A. Shutemov
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] x86/mm/hotplug: fix BUG_ON() after hotremove
@ 2017-06-07 10:47 ` Kirill A. Shutemov
0 siblings, 0 replies; 8+ messages in thread
From: Kirill A. Shutemov @ 2017-06-07 10:47 UTC (permalink / raw)
To: Jérôme Glisse
Cc: linux-kernel, linux-mm, Andy Lutomirski, Ingo Molnar,
Kirill A . Shutemov, Logan Gunthorpe
On Tue, Jun 06, 2017 at 01:35:12PM -0400, Jerome Glisse wrote:
> 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 code re-added that code f2a6a705 and
> thus we now trigger a BUG_ON() l128 in sync_global_pgds()
>
> This patch remove free_pud() like in af2cf278ef4f
Good catch. Thanks!
But I think we only need to skip free_pud_table() for 4-level paging.
If we don't we would leave 513 page tables around instead of one in
5-level paging case.
I don't think it's acceptable.
And please use patch subject lines along with commit hashes to simplify
reading commit message.
--
Kirill A. Shutemov
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] x86/mm/hotplug: fix BUG_ON() after hotremove
2017-06-07 10:47 ` Kirill A. Shutemov
@ 2017-06-07 14:49 ` Jerome Glisse
-1 siblings, 0 replies; 8+ messages in thread
From: Jerome Glisse @ 2017-06-07 14:49 UTC (permalink / raw)
To: Kirill A. Shutemov
Cc: linux-kernel, linux-mm, Andy Lutomirski, Ingo Molnar,
Kirill A . Shutemov, Logan Gunthorpe
On Wed, Jun 07, 2017 at 01:47:15PM +0300, Kirill A. Shutemov wrote:
> On Tue, Jun 06, 2017 at 01:35:12PM -0400, Jérôme Glisse wrote:
> > 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 code re-added that code f2a6a705 and
> > thus we now trigger a BUG_ON() l128 in sync_global_pgds()
> >
> > This patch remove free_pud() like in af2cf278ef4f
>
> Good catch. Thanks!
>
> But I think we only need to skip free_pud_table() for 4-level paging.
> If we don't we would leave 513 page tables around instead of one in
> 5-level paging case.
>
> I don't think it's acceptable.
>
> And please use patch subject lines along with commit hashes to simplify
> reading commit message.
>
I sent a v2 that disable free_pud in 4 level page table config.
Note that your patchset that allow switching between 4 and 5 at
boot time will need to update that code. As this patch is a fix
and your boot time switching is an RFC i assume the fix will go
in first.
Cheers,
Jérôme
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] x86/mm/hotplug: fix BUG_ON() after hotremove
@ 2017-06-07 14:49 ` Jerome Glisse
0 siblings, 0 replies; 8+ messages in thread
From: Jerome Glisse @ 2017-06-07 14:49 UTC (permalink / raw)
To: Kirill A. Shutemov
Cc: linux-kernel, linux-mm, Andy Lutomirski, Ingo Molnar,
Kirill A . Shutemov, Logan Gunthorpe
On Wed, Jun 07, 2017 at 01:47:15PM +0300, Kirill A. Shutemov wrote:
> On Tue, Jun 06, 2017 at 01:35:12PM -0400, Jerome Glisse wrote:
> > 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 code re-added that code f2a6a705 and
> > thus we now trigger a BUG_ON() l128 in sync_global_pgds()
> >
> > This patch remove free_pud() like in af2cf278ef4f
>
> Good catch. Thanks!
>
> But I think we only need to skip free_pud_table() for 4-level paging.
> If we don't we would leave 513 page tables around instead of one in
> 5-level paging case.
>
> I don't think it's acceptable.
>
> And please use patch subject lines along with commit hashes to simplify
> reading commit message.
>
I sent a v2 that disable free_pud in 4 level page table config.
Note that your patchset that allow switching between 4 and 5 at
boot time will need to update that code. As this patch is a fix
and your boot time switching is an RFC i assume the fix will go
in first.
Cheers,
Jerome
--
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^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2017-06-07 14:50 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-06-06 17:35 [PATCH] x86/mm/hotplug: fix BUG_ON() after hotremove Jérôme Glisse
2017-06-06 17:35 ` Jérôme Glisse
2017-06-06 19:50 ` Logan Gunthorpe
2017-06-06 19:50 ` Logan Gunthorpe
2017-06-07 10:47 ` Kirill A. Shutemov
2017-06-07 10:47 ` Kirill A. Shutemov
2017-06-07 14:49 ` Jerome Glisse
2017-06-07 14:49 ` Jerome Glisse
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