Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on 32bit and 64bit.
On 64bit, let's use MSB 56 (LSB 7), located right next to the page type.
On 32bit, let's use LSB 2 to avoid stealing one bit from the swap offset.
There seems to be no real reason why these bits cannot be used for swap
PTEs. The important part is that _PAGE_PRESENT and _PAGE_HASHPTE remain
0.
While at it, mask the type in __swp_entry() and remove _PAGE_BIT_SWAP_TYPE
from pte-e500.h: while it was used in 64bit code it was ignored in 32bit
code.
Link: https://lkml.kernel.org/r/20230113171026.582290-19-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
We already implemented support for 64bit book3s in commit bff9beaa2e
("powerpc/pgtable: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE for book3s")
Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE also in 32bit by reusing yet
unused LSB 2 / MSB 29. There seems to be no real reason why that bit
cannot be used, and reusing it avoids having to steal one bit from the
swap offset.
While at it, mask the type in __swp_entry().
Link: https://lkml.kernel.org/r/20230113171026.582290-18-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
nios2 disables swap for a good reason: it doesn't even provide sufficient
type bits as required by core MM. However, swap entries are nowadays also
used for other purposes (migration entries, PTE markers, HWPoison, ...),
and accidential use could be problematic.
Let's properly use 5 bits for the swap type and document the layout. Bits
26--31 should get ignored by hardware completely, so they can be used.
Link: https://lkml.kernel.org/r/20230113171026.582290-14-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE.
On 64bit, steal one bit from the type. Generic MM currently only uses 5
bits for the type (MAX_SWAPFILES_SHIFT), so the stolen bit is effectively
unused.
On 32bit we're able to locate unused bits. As the PTE layout for 32 bit
is very confusing, document it a bit better.
While at it, mask the type in __swp_entry()/mk_swap_pte().
Link: https://lkml.kernel.org/r/20230113171026.582290-13-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE by stealing one bit from the
type. Generic MM currently only uses 5 bits for the type
(MAX_SWAPFILES_SHIFT), so the stolen bit is effectively unused.
The shift by 2 when converting between PTE and arch-specific swap entry
makes the swap PTE layout a little bit harder to decipher.
While at it, drop the comment from paulus---copy-and-paste leftover from
powerpc where we actually have _PAGE_HASHPTE---and mask the type in
__swp_entry_to_pte() as well.
Link: https://lkml.kernel.org/r/20230113171026.582290-12-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Michal Simek <monstr@monstr.eu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE by stealing one bit from the
type. Generic MM currently only uses 5 bits for the type
(MAX_SWAPFILES_SHIFT), so the stolen bit is effectively unused.
While at it, make sure for sun3 that the valid bit never gets set by
properly masking it off and mask the type in __swp_entry().
Link: https://lkml.kernel.org/r/20230113171026.582290-11-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE by stealing one bit from the
type. Generic MM currently only uses 5 bits for the type
(MAX_SWAPFILES_SHIFT), so the stolen bit is effectively unused.
While at it, also mask the type in mk_swap_pte().
Note that this bit does not conflict with swap PMDs and could also be used
in swap PMD context later.
Link: https://lkml.kernel.org/r/20230113171026.582290-9-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE by stealing one bit from the
offset. This reduces the maximum swap space per file to 16 GiB (was 32
GiB).
We might actually be able to reuse one of the other software bits
(_PAGE_READ / PAGE_WRITE) instead, because we only have to keep
pte_present(), pte_none() and HW happy. For now, let's keep it simple
because there might be something non-obvious.
Link: https://lkml.kernel.org/r/20230113171026.582290-6-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Guo Ren <guoren@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE by stealing one bit from the
offset. This reduces the maximum swap space per file to 64 GiB (was 128
GiB).
While at it drop the PTE_TYPE_FAULT from __swp_entry_to_pte() which is
defined to be 0 and is rather confusing because we should be dealing with
"Linux PTEs" not "hardware PTEs". Also, properly mask the type in
__swp_entry().
Link: https://lkml.kernel.org/r/20230113171026.582290-5-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This brings mlock in line with the folio batches declared in mm/swap.c and
makes the code more consistent across the two.
The existing mechanism for identifying which operation each folio in the
batch is undergoing is maintained, i.e. using the lower 2 bits of the
struct folio address (previously struct page address). This should
continue to function correctly as folios remain at least system
word-aligned.
All invocations of mlock() pass either a non-compound page or the head of
a THP-compound page and no tail pages need updating so this functionality
works with struct folios being used internally rather than struct pages.
In this patch the external interface is kept identical to before in order
to maintain separation between patches in the series, using a rather
awkward conversion from struct page to struct folio in relevant functions.
However, this maintenance of the existing interface is intended to be
temporary - the next patch in the series will update the interfaces to
accept folios directly.
Link: https://lkml.kernel.org/r/9f894d54d568773f4ed3cb0eef5f8932f62c95f4.1673526881.git.lstoakes@gmail.com
Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "convert hugepage memory failure functions to folios".
This series contains a 1:1 straightforward page to folio conversion for
memory failure functions which deal with huge pages. I renamed a few
functions to fit with how other folio operating functions are named.
These include:
hugetlb_clear_page_hwpoison -> folio_clear_hugetlb_hwpoison
free_raw_hwp_pages -> folio_free_raw_hwp
__free_raw_hwp_pages -> __folio_free_raw_hwp
hugetlb_set_page_hwpoison -> folio_set_hugetlb_hwpoison
The goal of this series was to reduce users of the hugetlb specific page
flag macros which take in a page so users are protected by the compiler to
make sure they are operating on a head page.
This patch (of 8):
Use a folio throughout the function rather than using a head page. This
also reduces the users of the page version of hugetlb specific page flags.
Link: https://lkml.kernel.org/r/20230112204608.80136-2-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "Get rid of tail page fields".
Continue the shrinkage of the struct page definition by getting rid of the
'first tail page' and 'second tail page' fields. I originally did this
patch set before Hugh's rewrite of the subpages_mapcount, so it needed
substantial updates; hope I didn't miss anything.
This patch (of 28):
commit dad6a5eb5556(mm,hugetlb: use folio fields in second tail page)
added a transitional hugetlb field to struct page and struct folio to make
room for another int in the first tail of a compound page. Hugetlb folio
conversions have changed all page users of this field to use the fields
within the folio so struct page no longer needs this hugetlb specific
field.
Link: https://lkml.kernel.org/r/20230111142915.1001531-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20230111142915.1001531-29-willy@infradead.org
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Remove the entire block of definitions for the second tail page, and add
the deferred list to the struct folio. This actually moves _deferred_list
to a different offset in struct folio because I don't see a need to
include the padding.
This lets us use list_for_each_entry_safe() in deferred_split_scan()
and avoid a number of calls to compound_head().
Link: https://lkml.kernel.org/r/20230111142915.1001531-25-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
