On Tue, 22 Aug 2023, Matthew Wilcox wrote:
> On Tue, Aug 22, 2023 at 11:34:19AM -0700, Hugh Dickins wrote:
> > (Yes, the locking is a bit confusing: but mainly for the unrelated reason,
> > that with the split locking configs, we never quite know whether this lock
> > is
On Tue, 22 Aug 2023, Jann Horn wrote:
> On Tue, Aug 22, 2023 at 4:51 AM Hugh Dickins wrote:
> > On Mon, 21 Aug 2023, Jann Horn wrote:
> > > On Mon, Aug 21, 2023 at 9:51 PM Hugh Dickins wrote:
> > > > Just for this case, take the pmd_lock() two steps earlier: no
On Mon, 21 Aug 2023, Jann Horn wrote:
> On Mon, Aug 21, 2023 at 9:51 PM Hugh Dickins wrote:
> > Jann Horn demonstrated how userfaultfd ioctl UFFDIO_COPY into a private
> > shmem mapping can add valid PTEs to page table collapse_pte_mapped_thp()
> > thought it had emptied:
VTu_a9h=rg5fw-kyd5rg5xo_rdbm0ltt...@mail.gmail.com/
Fixes: 1043173eb5eb ("mm/khugepaged: collapse_pte_mapped_thp() with
mmap_read_lock()")
Signed-off-by: Hugh Dickins
---
mm/khugepaged.c | 38 +-
1 file changed, 29 insertions(+), 9 deletions(-)
diff --git
On Mon, 14 Aug 2023, Jann Horn wrote:
> On Wed, Jul 12, 2023 at 6:42 AM Hugh Dickins wrote:
> > Bring collapse_and_free_pmd() back into collapse_pte_mapped_thp().
> > It does need mmap_read_lock(), but it does not need mmap_write_lock(),
> > nor vma_start_write() nor i_mmap l
On Tue, 15 Aug 2023, David Hildenbrand wrote:
> On 15.08.23 08:34, Hugh Dickins wrote:
> > On Mon, 14 Aug 2023, Jann Horn wrote:
> >>
> >> /* step 4: remove page table */
> >> + if (strcmp(current->comm, "DELAYME") == 0) {
> >
On Mon, 14 Aug 2023, Jann Horn wrote:
> On Wed, Jul 12, 2023 at 6:42 AM Hugh Dickins wrote:
> > Bring collapse_and_free_pmd() back into collapse_pte_mapped_thp().
> > It does need mmap_read_lock(), but it does not need mmap_write_lock(),
> > nor vma_start_write() nor i_mmap l
Use ptep_clear() instead of pte_clear(): when CONFIG_PAGE_TABLE_CHECK=y,
ptep_clear() adds some accounting, missing which would cause a BUG later.
Signed-off-by: Hugh Dickins
Reported-by: Qi Zheng
Closes:
https://lore.kernel.org/linux-mm/0df84f9f-e9b0-80b1-4c9e-95abc1a73...@bytedance.com
On Thu, 3 Aug 2023, Qi Zheng wrote:
> On 2023/7/12 12:42, Hugh Dickins wrote:
> > Bring collapse_and_free_pmd() back into collapse_pte_mapped_thp().
> > It does need mmap_read_lock(), but it does not need mmap_write_lock(),
> > nor vma_start_write() nor i_mmap lock nor anon_
On Mon, 24 Jul 2023, Vishal Moola (Oracle) wrote:
> The MM subsystem is trying to shrink struct page. This patchset
> introduces a memory descriptor for page table tracking - struct ptdesc.
>
> This patchset introduces ptdesc, splits ptdesc from struct page, and
> converts many callers of page
Though not yet detected by syzbot, this commit was making the same
mistake with mmap_locked as the previous commit: fix that.
Signed-off-by: Hugh Dickins
---
mm/khugepaged.c | 8 +++-
1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index
tmail.com
Closes:
https://lore.kernel.org/linux-mm/e4b0f0060123c...@google.com/
Signed-off-by: Hugh Dickins
---
mm/khugepaged.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 6bad69c0e4bd..1c773db26e88 100644
--- a/mm/khugepaged.c
+++ b/mm
Claudio finds warning on mm_has_pgste() more useful than on mm_alloc_pgste().
Signed-off-by: Hugh Dickins
---
arch/s390/mm/pgalloc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/s390/mm/pgalloc.c b/arch/s390/mm/pgalloc.c
index 760b4ace475e..d7374add7820 100644
()
in assert_pte_locked(). BUG if pte_offset_map_nolock() fails.
Signed-off-by: Hugh Dickins
---
arch/powerpc/mm/pgtable.c | 8
1 file changed, 8 insertions(+)
diff --git a/arch/powerpc/mm/pgtable.c b/arch/powerpc/mm/pgtable.c
index 16b061af86d7..a3dcdb2d5b4b 100644
--- a/arch/powerpc/mm/pgtable.c
On Tue, 18 Jul 2023, Aneesh Kumar K.V wrote:
> Hugh Dickins writes:
>
> > Instead of pte_lockptr(), use the recently added pte_offset_map_nolock()
> > in assert_pte_locked(). BUG if pte_offset_map_nolock() fails: this is
> > stricter than the previous implementation, whi
mmap_write_trylock() and vma_try_start_write() were added just for
khugepaged, but now it has no use for them: delete.
Signed-off-by: Hugh Dickins
---
This is the version which applies to mm-unstable or linux-next.
include/linux/mm.h| 17 -
include/linux/mmap_lock.h
Add a block of comments on pte_offset_map_lock(), pte_offset_map() and
pte_offset_map_nolock() to mm/pgtable-generic.c, to help explain them.
Signed-off-by: Hugh Dickins
---
mm/pgtable-generic.c | 44
1 file changed, 44 insertions(+)
diff --git a/mm
mmap_write_trylock() and vma_try_start_write() were added just for
khugepaged, but now it has no use for them: delete.
Signed-off-by: Hugh Dickins
---
include/linux/mm.h| 17 -
include/linux/mmap_lock.h | 10 --
2 files changed, 27 deletions(-)
diff --git
be recollapsed. Call collapse_pte_mapped_thp()
directly in this case (why was it deferred before? I assume an issue
with needing mmap_lock for write, but now it's only needed for read).
Signed-off-by: Hugh Dickins
---
mm/khugepaged.c | 125 +++---
1 file changed
ut with those
entries now cleared, "step 4" (after dropping ptl to do pmd_lock) is kept
safe by the huge page lock, which stops new PTEs from being faulted in.
Signed-off-by: Hugh Dickins
---
mm/khugepaged.c | 172 ++
1 file changed,
to replace_page_tables(), which
inserts the final huge pmd without mmap lock: going through an invalid
state instead of pmd_none() followed by fault. But that enhancement
does raise some more questions: leave it until a later release.
Signed-off-by: Hugh Dickins
---
mm/khugepaged.c | 184
(none of whose pte_free()s use the mm arg which was passed to it).
Signed-off-by: Hugh Dickins
---
include/linux/mm_types.h | 4
include/linux/pgtable.h | 2 ++
mm/pgtable-generic.c | 20
3 files changed, 26 insertions(+)
diff --git a/include/linux/mm_types.h b
remove_table(), where we might not have a stable mm any more.
Signed-off-by: Hugh Dickins
Reviewed-by: Gerald Schaefer
---
arch/s390/include/asm/pgalloc.h | 4 ++
arch/s390/mm/pgalloc.c | 80 +--
2 files changed, 72 insertions(+), 12 deletions(-)
diff --git
.
sparc32 supports pagetables sharing a page, but does not support THP;
sparc64 supports THP, but does not support pagetables sharing a page.
So the sparc-specific pte_free_defer() is as simple as the generic one,
except for converting between pte_t *pgtable_t and struct page *.
Signed-off-by: Hugh
pte_fragment_free() directly; and there call_rcu() to
pte_free_now() when last fragment is freed and the page is PageActive.
Suggested-by: Jason Gunthorpe
Signed-off-by: Hugh Dickins
---
arch/powerpc/include/asm/pgalloc.h | 4
arch/powerpc/mm/pgtable-frag.c | 29
, if an assert_pte_locked() caller can be racing such transitions?
This mod might cause new crashes: which either expose my ignorance, or
indicate issues to be fixed, or limit the usage of assert_pte_locked().
Signed-off-by: Hugh Dickins
---
arch/powerpc/mm/pgtable.c | 16 ++--
1
-by: Hugh Dickins
---
arch/arm/mm/fault-armv.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/arch/arm/mm/fault-armv.c b/arch/arm/mm/fault-armv.c
index ca5302b0b7ee..7cb125497976 100644
--- a/arch/arm/mm/fault-armv.c
+++ b/arch/arm/mm/fault-armv.c
@@ -117,11 +117,10 @@ static
).
Signed-off-by: Hugh Dickins
---
include/linux/pgtable.h | 4
mm/pgtable-generic.c| 29 +
2 files changed, 33 insertions(+)
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 5134edcec668..7f2db400f653 100644
--- a/include/linux/pgtable.h
-by: Hugh Dickins
---
include/linux/pgtable.h | 4 ++--
mm/pgtable-generic.c| 4 ++--
2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 5063b482e34f..5134edcec668 100644
--- a/include/linux/pgtable.h
+++ b/include/linux
Here is v3 of the series of patches to mm (and a few architectures), based
on v6.5-rc1 which includes the preceding two series (thank you!): in which
khugepaged takes advantage of pte_offset_map[_lock]() allowing for pmd
transitions. Differences from v1 and v2 are noted patch by patch below.
wly mapped VMA which can be modified after it
becomes visible")
Cc: sta...@vger.kernel.org
Signed-off-by: Hugh Dickins
---
mm/mmap.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/mm/mmap.c b/mm/mmap.c
index 84c71431a527..3eda23c9ebe7 100644
--- a/mm/mmap.c
+++ b/mm
On Thu, 6 Jul 2023, Gerald Schaefer wrote:
>
> Since none of my remarks on the comments seem valid or strictly necessary
> any more, and I also could not find functional issues, I think you can add
> this patch as new version for 07/12. And I can now give you this:
>
> Reviewed-by: Gerald
x13c/0x520
> get_arg_page+0x80/0x1d0
> copy_string_kernel+0xc8/0x250
> kernel_execve+0x11c/0x270
> run_init_process+0xe4/0x10c
> kernel_init+0xbc/0x1a0
> ret_from_kernel_user_thread+0x14/0x1c
>
> Cc: Hugh Dickins
> Reported-by: Michael Ellerman
> Signed-off-by:
On Wed, 5 Jul 2023, Gerald Schaefer wrote:
> On Tue, 4 Jul 2023 10:03:57 -0700 (PDT)
> Hugh Dickins wrote:
> > On Tue, 4 Jul 2023, Gerald Schaefer wrote:
> > > On Sat, 1 Jul 2023 21:32:38 -0700 (PDT)
> > > Hugh Dickins wrote:
> > > &g
On Wed, 5 Jul 2023, Alexander Gordeev wrote:
> On Sat, Jul 01, 2023 at 09:32:38PM -0700, Hugh Dickins wrote:
> > On Thu, 29 Jun 2023, Hugh Dickins wrote:
>
> Hi Hugh,
>
> ...
>
> > +#ifdef CONFIG_TRANSPARENT_HUGEPAGE
> > +void pte_free_defer(str
On Tue, 4 Jul 2023, Gerald Schaefer wrote:
> On Sat, 1 Jul 2023 21:32:38 -0700 (PDT)
> Hugh Dickins wrote:
> > On Thu, 29 Jun 2023, Hugh Dickins wrote:
> > >
> > > I've grown to dislike the (ab)use of pt_frag_refcount even more, to the
> > > extent that
On Tue, 4 Jul 2023, Alexander Gordeev wrote:
> On Sat, Jul 01, 2023 at 09:32:38PM -0700, Hugh Dickins wrote:
> > On Thu, 29 Jun 2023, Hugh Dickins wrote:
>
> Hi Hugh,
>
> ...
> > No, not quite the same rules as before: I came to realize that using
> > list_
On Thu, 29 Jun 2023, Hugh Dickins wrote:
>
> I've grown to dislike the (ab)use of pt_frag_refcount even more, to the
> extent that I've not even tried to verify it; but I think I do get the
> point now, that we need further info than just PPHHAA to know whether
> the page
On Fri, 30 Jun 2023, Claudio Imbrenda wrote:
> On Fri, 30 Jun 2023 08:28:54 -0700 (PDT)
> Hugh Dickins wrote:
> > On Fri, 30 Jun 2023, Claudio Imbrenda wrote:
> > > On Tue, 20 Jun 2023 00:51:19 -0700 (PDT)
> > > Hugh Dickins wrote:
> > >
> > > [.
On Fri, 30 Jun 2023, Claudio Imbrenda wrote:
> On Tue, 20 Jun 2023 00:51:19 -0700 (PDT)
> Hugh Dickins wrote:
>
> [...]
>
> > +void pte_free_defer(struct mm_struct *mm, pgtable_t pgtable)
> > +{
> > + unsigned int bit, mask;
> > + struct page *page;
&g
On Thu, 29 Jun 2023, Gerald Schaefer wrote:
> On Thu, 29 Jun 2023 12:22:24 -0300
> Jason Gunthorpe wrote:
> > On Wed, Jun 28, 2023 at 10:08:08PM -0700, Hugh Dickins wrote:
> > > On Wed, 28 Jun 2023, Gerald Schaefer wrote:
> > > >
> > > > As disc
On Wed, 28 Jun 2023, Gerald Schaefer wrote:
>
> As discussed in the other thread, we would rather go with less complexity,
> possibly switching to an approach w/o the list and fragment re-use in the
> future. For now, as a first step in that direction, we can try with not
> adding fragments back
On Tue, 27 Jun 2023, Jason Gunthorpe wrote:
> On Wed, Jun 21, 2023 at 07:36:11PM -0700, Hugh Dickins wrote:
> > [PATCH v3 05/12] powerpc: add pte_free_defer() for pgtables sharing page
...
> Yes, this makes sense to me, very simple..
>
> I always for get these details but a
On Tue, 27 Jun 2023, Matthew Wilcox wrote:
> On Mon, Jun 26, 2023 at 09:44:08PM -0700, Hugh Dickins wrote:
> > On Mon, 26 Jun 2023, Vishal Moola (Oracle) wrote:
> >
> > > The MM subsystem is trying to shrink struct page. This patchset
> > > introduces a memory d
On Tue, 27 Jun 2023, David Hildenbrand wrote:
> On 27.06.23 06:44, Hugh Dickins wrote:
> > On Mon, 26 Jun 2023, Vishal Moola (Oracle) wrote:
> >
> >> The MM subsystem is trying to shrink struct page. This patchset
> >> introduces a memory descriptor for pa
On Mon, 26 Jun 2023, Vishal Moola (Oracle) wrote:
> The MM subsystem is trying to shrink struct page. This patchset
> introduces a memory descriptor for page table tracking - struct ptdesc.
...
> 39 files changed, 686 insertions(+), 455 deletions(-)
I don't see the point of this patchset: to me
On Tue, 20 Jun 2023, Jason Gunthorpe wrote:
> On Tue, Jun 20, 2023 at 12:54:25PM -0700, Hugh Dickins wrote:
> > On Tue, 20 Jun 2023, Jason Gunthorpe wrote:
> > > On Tue, Jun 20, 2023 at 12:47:54AM -0700, Hugh Dickins wrote:
> > > > Add powerpc-specific pte_free_d
On Tue, 20 Jun 2023, Jason Gunthorpe wrote:
> On Tue, Jun 20, 2023 at 12:47:54AM -0700, Hugh Dickins wrote:
> > Add powerpc-specific pte_free_defer(), to call pte_free() via call_rcu().
> > pte_free_defer() will be called inside khugepaged's retract_page_tables()
> > loop, w
ut with those
entries now cleared, "step 4" (after dropping ptl to do pmd_lock) is kept
safe by the huge page lock, which stops new PTEs from being faulted in.
Signed-off-by: Hugh Dickins
---
This is the version which applies to mm-everything or linux-next.
mm/khugepaged.c | 174 ++
mmap_write_trylock() and vma_try_start_write() were added just for
khugepaged, but now it has no use for them: delete.
Signed-off-by: Hugh Dickins
---
include/linux/mm.h| 17 -
include/linux/mmap_lock.h | 10 --
2 files changed, 27 deletions(-)
diff --git
be recollapsed. Call collapse_pte_mapped_thp()
directly in this case (why was it deferred before? I assume an issue
with needing mmap_lock for write, but now it's only needed for read).
Signed-off-by: Hugh Dickins
---
mm/khugepaged.c | 125 +++-
1 file changed
ut with those
entries now cleared, "step 4" (after dropping ptl to do pmd_lock) is kept
safe by the huge page lock, which stops new PTEs from being faulted in.
Signed-off-by: Hugh Dickins
---
mm/khugepaged.c | 172 ++--
1 file changed,
to replace_page_tables(), which
inserts the final huge pmd without mmap lock: going through an invalid
state instead of pmd_none() followed by fault. But that enhancement
does raise some more questions: leave it until a later release.
Signed-off-by: Hugh Dickins
---
mm/khugepaged.c | 184
(none of whose pte_free()s use the mm arg which was passed to it).
Signed-off-by: Hugh Dickins
---
include/linux/mm_types.h | 4
include/linux/pgtable.h | 2 ++
mm/pgtable-generic.c | 20
3 files changed, 26 insertions(+)
diff --git a/include/linux/mm_types.h b
atic global mm_pgtable_list_lock instead:
then a soon-to-follow commit will split it per-mm as before (probably by
using a SLAB_TYPESAFE_BY_RCU structure for the list head and its lock);
and update the commentary on the pgtable_list.
Signed-off-by: Hugh Dickins
---
arch/s390/include/asm/p
.
sparc32 supports pagetables sharing a page, but does not support THP;
sparc64 supports THP, but does not support pagetables sharing a page.
So the sparc-specific pte_free_defer() is as simple as the generic one,
except for converting between pte_t *pgtable_t and struct page *.
Signed-off-by: Hugh
if more deferrals arrived during its grace period.
Signed-off-by: Hugh Dickins
---
arch/powerpc/include/asm/pgalloc.h | 4 +++
arch/powerpc/mm/pgtable-frag.c | 51 ++
2 files changed, 55 insertions(+)
diff --git a/arch/powerpc/include/asm/pgalloc.h
b/arch/powerpc
, if an assert_pte_locked() caller can be racing such transitions?
This mod might cause new crashes: which either expose my ignorance, or
indicate issues to be fixed, or limit the usage of assert_pte_locked().
Signed-off-by: Hugh Dickins
---
arch/powerpc/mm/pgtable.c | 16 ++--
1
-by: Hugh Dickins
---
arch/arm/mm/fault-armv.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/arch/arm/mm/fault-armv.c b/arch/arm/mm/fault-armv.c
index ca5302b0b7ee..7cb125497976 100644
--- a/arch/arm/mm/fault-armv.c
+++ b/arch/arm/mm/fault-armv.c
@@ -117,11 +117,10 @@ static
).
Signed-off-by: Hugh Dickins
---
include/linux/pgtable.h | 4
mm/pgtable-generic.c| 29 +
2 files changed, 33 insertions(+)
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 8b0fc7fdc46f..525f1782b466 100644
--- a/include/linux/pgtable.h
-by: Hugh Dickins
---
include/linux/pgtable.h | 4 ++--
mm/pgtable-generic.c| 4 ++--
2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index a1326e61d7ee..8b0fc7fdc46f 100644
--- a/include/linux/pgtable.h
+++ b/include/linux
Here is v2 third series of patches to mm (and a few architectures), based
on v6.4-rc5 with the preceding two series applied: in which khugepaged
takes advantage of pte_offset_map[_lock]() allowing for pmd transitions.
Differences from v1 are noted patch by patch below
This follows on from the v2
-by: Nathan Chancellor
Signed-off-by: Hugh Dickins
---
Andrew, please replace my mips patch, and its build warning fix patch,
in mm-unstable by this less ambitious but working replacement - thanks.
arch/mips/mm/tlb-r4k.c | 12 ++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff
On Thu, 15 Jun 2023, Nathan Chancellor wrote:
> On Wed, Jun 14, 2023 at 10:43:30PM -0700, Hugh Dickins wrote:
> >
> > I do hope that you find the first fixes the breakage; but if not, then
>
> I hate to be the bearer of bad news but the first patch did not fix the
>
On Mon, 12 Jun 2023, Vishal Moola (Oracle) wrote:
> Currently, page table information is stored within struct page. As part
> of simplifying struct page, create struct ptdesc for page table
> information.
>
> Signed-off-by: Vishal Moola (Oracle)
Vishal, as I think you have already guessed,
On Wed, 14 Jun 2023, Hugh Dickins wrote:
> On Wed, 14 Jun 2023, Nathan Chancellor wrote:
> >
> > I just bisected a crash while powering down a MIPS machine in QEMU to
> > this change as commit 8044511d3893 ("mips: update_mmu_cache() can
> > replace __update_tlb()
On Wed, 14 Jun 2023, Nathan Chancellor wrote:
> Hi Hugh,
>
> On Thu, Jun 08, 2023 at 12:17:24PM -0700, Hugh Dickins wrote:
> > Don't make update_mmu_cache() a wrapper around __update_tlb(): call it
> > directly, and use the ptep (or pmdp) provided by the caller, inst
!
Reported-by: kernel test robot
Closes:
https://lore.kernel.org/oe-kbuild-all/202306091304.cnvispk0-...@intel.com/
Signed-off-by: Hugh Dickins
---
arch/mips/mm/tlb-r4k.c | 10 ++
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/arch/mips/mm/tlb-r4k.c b/arch/mips/mm/tlb
To keep balance in future, remember to pte_unmap() after a successful
pte_offset_map(). And act as if get_pte_for_vaddr() really needs a map
there, to read the pteval before "unmapping", to be sure page table is
not removed.
Signed-off-by: Hugh Dickins
---
arch/xtensa/mm/tlb.c |
sme_populate_pgd() is an __init function for sme_encrypt_kernel():
it should use pte_offset_kernel() instead of pte_offset_map(), to avoid
the question of whether a pte_unmap() will be needed to balance.
Signed-off-by: Hugh Dickins
---
arch/x86/mm/mem_encrypt_identity.c | 2 +-
1 file changed
In rare transient cases, not yet made possible, pte_offset_map() and
pte_offset_map_lock() may not find a page table: handle appropriately.
Signed-off-by: Hugh Dickins
---
arch/x86/kernel/ldt.c | 6 --
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/ldt.c b
iounit_alloc() and sbus_iommu_alloc() are working from pmd_off_k(),
so should use pte_offset_kernel() instead of pte_offset_map(), to avoid
the question of whether a pte_unmap() will be needed to balance.
Signed-off-by: Hugh Dickins
---
arch/sparc/mm/io-unit.c | 2 +-
arch/sparc/mm/iommu.c
In rare transient cases, not yet made possible, pte_offset_map() and
pte_offset_map_lock() may not find a page table: handle appropriately.
Signed-off-by: Hugh Dickins
---
arch/sparc/kernel/signal32.c | 2 ++
arch/sparc/mm/fault_64.c | 3 +++
arch/sparc/mm/tlb.c | 2 ++
3 files
pte_alloc_map() expects to be followed by pte_unmap(), but hugetlb omits
that: to keep balance in future, use the recently added pte_alloc_huge()
instead; with pte_offset_huge() a better name for pte_offset_kernel().
Signed-off-by: Hugh Dickins
---
arch/sparc/mm/hugetlbpage.c | 4 ++--
1 file
pte_alloc_map() expects to be followed by pte_unmap(), but hugetlb omits
that: to keep balance in future, use the recently added pte_alloc_huge()
instead; with pte_offset_huge() a better name for pte_offset_kernel().
Signed-off-by: Hugh Dickins
---
arch/sh/mm/hugetlbpage.c | 4 ++--
1 file
pte_alloc_map_lock() expects to be followed by pte_unmap_unlock(): to
keep balance in future, pass ptep as well as ptl to gmap_pte_op_end(),
and use pte_unmap_unlock() instead of direct spin_unlock() (even though
ptep ends up unused inside the macro).
Signed-off-by: Hugh Dickins
Acked
In rare transient cases, not yet made possible, pte_offset_map() and
pte_offset_map_lock() may not find a page table: handle appropriately.
Add comment on mm's contract with s390 above __zap_zero_pages(),
and fix old comment there: must be called after THP was disabled.
Signed-off-by: Hugh
pte_alloc_map() expects to be followed by pte_unmap(), but hugetlb omits
that: to keep balance in future, use the recently added pte_alloc_huge()
instead; with pte_offset_huge() a better name for pte_offset_kernel().
Signed-off-by: Hugh Dickins
Reviewed-by: Alexandre Ghiti
Acked-by: Palmer
-off-by: Hugh Dickins
---
arch/powerpc/mm/hugetlbpage.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index b900933507da..f7c683b672c1 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
In rare transient cases, not yet made possible, pte_offset_map() and
pte_offset_map_lock() may not find a page table: handle appropriately.
Balance successful pte_offset_map() with pte_unmap() where omitted.
Signed-off-by: Hugh Dickins
---
arch/powerpc/mm/book3s64/hash_tlb.c | 4
arch
with kvmppc races beween page
table and huge entry, of the kind which we are expecting to address
in pte_offset_map() - this might want to be revisited in future.
Signed-off-by: Hugh Dickins
---
arch/powerpc/kvm/book3s_64_mmu_radix.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git
pte_alloc_map() expects to be followed by pte_unmap(), but hugetlb omits
that: to keep balance in future, use the recently added pte_alloc_huge()
instead; with pte_offset_huge() a better name for pte_offset_kernel().
Signed-off-by: Hugh Dickins
---
arch/parisc/mm/hugetlbpage.c | 4 ++--
1 file
unmap_uncached_pte() is working from pgd_offset_k(vaddr), so it should
use pte_offset_kernel() instead of pte_offset_map(), to avoid the
question of whether a pte_unmap() will be needed to balance.
Signed-off-by: Hugh Dickins
---
arch/parisc/kernel/pci-dma.c | 2 +-
1 file changed, 1 insertion
To keep balance in future, remember to pte_unmap() after a successful
get_ptep(). And act as if flush_cache_pages() really needs a map there,
to read the pfn before "unmapping", to be sure page table is not removed.
Signed-off-by: Hugh Dickins
---
arch/parisc/kernel/ca
; provided by the caller is actually the pmdp,
instead of testing pmd_huge(): or test pmd_huge() too and warn if it
disagrees? This is "hazardous" territory: needs review and testing.
Signed-off-by: Hugh Dickins
---
arch/mips/include/asm/pgtable.h | 15 +++
arch/mips/mm/tlb-r3k.c
In rare transient cases, not yet made possible, pte_offset_map() and
pte_offset_map_lock() may not find a page table: handle appropriately.
Signed-off-by: Hugh Dickins
---
arch/microblaze/kernel/signal.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/microblaze
In rare transient cases, not yet made possible, pte_offset_map() and
pte_offset_map_lock() may not find a page table: handle appropriately.
Restructure cf_tlb_miss() with a pte_unmap() (previously omitted)
at label out, followed by one local_irq_restore() for all.
Signed-off-by: Hugh Dickins
pte_alloc_map() expects to be followed by pte_unmap(), but hugetlb omits
that: to keep balance in future, use the recently added pte_alloc_huge()
instead; with pte_offset_huge() a better name for pte_offset_kernel().
Signed-off-by: Hugh Dickins
---
arch/ia64/mm/hugetlbpage.c | 4 ++--
1 file
pte_alloc_map() expects to be followed by pte_unmap(), but hugetlb omits
that: to keep balance in future, use the recently added pte_alloc_huge()
instead; with pte_offset_huge() a better name for pte_offset_kernel().
Signed-off-by: Hugh Dickins
Acked-by: Catalin Marinas
---
arch/arm64/mm
In rare transient cases, not yet made possible, pte_offset_map() and
pte_offset_map_lock() may not find a page table: handle appropriately.
Signed-off-by: Hugh Dickins
Acked-by: Catalin Marinas
---
arch/arm64/mm/fault.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/arm64/mm
In rare transient cases, not yet made possible, pte_offset_map() and
pte_offset_map_lock() may not find a page table: handle appropriately.
Signed-off-by: Hugh Dickins
---
arch/arm/lib/uaccess_with_memcpy.c | 3 +++
arch/arm/mm/fault-armv.c | 5 -
arch/arm/mm/fault.c
Here is v2 series of patches to various architectures, based on v6.4-rc5:
preparing for v2 of changes following in mm, affecting pte_offset_map()
and pte_offset_map_lock(). There are very few differences from v1:
noted patch by patch below.
v1 was "arch: allow pte_offset_map[_lock]() to fail"
On Tue, 6 Jun 2023, Gerald Schaefer wrote:
> On Mon, 5 Jun 2023 22:11:52 -0700 (PDT)
> Hugh Dickins wrote:
> > On Thu, 1 Jun 2023 15:57:51 +0200
> > Gerald Schaefer wrote:
> > >
> > > Yes, we have 2 pagetables in one 4K page, which could result in same
> &
On Tue, 6 Jun 2023, Jason Gunthorpe wrote:
> On Mon, Jun 05, 2023 at 10:11:52PM -0700, Hugh Dickins wrote:
>
> > "deposited" pagetable fragments, over in arch/s390/mm/pgtable.c: use
> > the first two longs of the page table itself for threading the list.
>
>
On Tue, 6 Jun 2023, Jason Gunthorpe wrote:
> On Tue, Jun 06, 2023 at 03:03:31PM -0400, Peter Xu wrote:
> > On Tue, Jun 06, 2023 at 03:23:30PM -0300, Jason Gunthorpe wrote:
> > > On Mon, Jun 05, 2023 at 08:40:01PM -0700, Hugh Dickins wrote:
> > >
> > > > diff
On Fri, 2 Jun 2023, Jann Horn wrote:
> On Fri, Jun 2, 2023 at 6:37 AM Hugh Dickins wrote:
>
> > The most obvious vital thing (in the split ptlock case) is that it
> > remains a struct page with a usable ptl spinlock embedded in it.
> >
> > The question becomes
On Wed, 31 May 2023, Jann Horn wrote:
> On Mon, May 29, 2023 at 8:25 AM Hugh Dickins wrote:
> > +static void retract_page_tables(struct address_space *mapping, pgoff_t
> > pgoff)
...
> > +* Note that vma->anon_vma check is racy:
On Sun, 28 May 2023, Hugh Dickins wrote:
> Add s390-specific pte_free_defer(), to call pte_free() via call_rcu().
> pte_free_defer() will be called inside khugepaged's retract_page_tables()
> loop, where allocating extra memory cannot be relied upon. This precedes
> the generic vers
On Sun, 28 May 2023, Hugh Dickins wrote:
> Add sparc-specific pte_free_defer(), to call pte_free() via call_rcu().
> pte_free_defer() will be called inside khugepaged's retract_page_tables()
> loop, where allocating extra memory cannot be relied upon. This precedes
> the generic vers
On Fri, 2 Jun 2023, Jason Gunthorpe wrote:
> On Mon, May 29, 2023 at 03:02:02PM +0100, Matthew Wilcox wrote:
> > On Sun, May 28, 2023 at 11:20:21PM -0700, Hugh Dickins wrote:
> > > +void pte_free_defer(struct mm_struct *mm, pgtable_t pgtable)
> > > +
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