The quilt patch titled
Subject: mm/gup: remove FOLL_MIGRATION
has been removed from the -mm tree. Its filename was
mm-gup-remove-foll_migration.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: David Hildenbrand <david@xxxxxxxxxx>
Subject: mm/gup: remove FOLL_MIGRATION
Date: Fri, 21 Oct 2022 12:11:41 +0200
Fortunately, the last user (KSM) is gone, so let's just remove this rather
special code from generic GUP handling -- especially because KSM never
required the PMD handling as KSM only deals with individual base pages.
[akpm@xxxxxxxxxxxxxxxxxxxx: fix merge snafu]Link: https://lkml.kernel.org/r/20221021101141.84170-10-david@xxxxxxxxxx
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Peter Xu <peterx@xxxxxxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/mm.h | 1
mm/gup.c | 55 +++----------------------------------------
2 files changed, 5 insertions(+), 51 deletions(-)
--- a/include/linux/mm.h~mm-gup-remove-foll_migration
+++ a/include/linux/mm.h
@@ -3057,7 +3057,6 @@ struct page *follow_page(struct vm_area_
* and return without waiting upon it */
#define FOLL_NOFAULT 0x80 /* do not fault in pages */
#define FOLL_HWPOISON 0x100 /* check page is hwpoisoned */
-#define FOLL_MIGRATION 0x400 /* wait for page to replace migration entry */
#define FOLL_TRIED 0x800 /* a retry, previous pass started an IO */
#define FOLL_REMOTE 0x2000 /* we are working on non-current tsk/mm */
#define FOLL_ANON 0x8000 /* don't do file mappings */
--- a/mm/gup.c~mm-gup-remove-foll_migration
+++ a/mm/gup.c
@@ -537,30 +537,13 @@ static struct page *follow_page_pte(stru
if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) ==
(FOLL_PIN | FOLL_GET)))
return ERR_PTR(-EINVAL);
-retry:
if (unlikely(pmd_bad(*pmd)))
return no_page_table(vma, flags);
ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
pte = *ptep;
- if (!pte_present(pte)) {
- swp_entry_t entry;
- /*
- * KSM's break_ksm() relies upon recognizing a ksm page
- * even while it is being migrated, so for that case we
- * need migration_entry_wait().
- */
- if (likely(!(flags & FOLL_MIGRATION)))
- goto no_page;
- if (pte_none(pte))
- goto no_page;
- entry = pte_to_swp_entry(pte);
- if (!is_migration_entry(entry))
- goto no_page;
- pte_unmap_unlock(ptep, ptl);
- migration_entry_wait(mm, pmd, address);
- goto retry;
- }
+ if (!pte_present(pte))
+ goto no_page;
if (pte_protnone(pte) && !gup_can_follow_protnone(flags))
goto no_page;
@@ -668,28 +651,8 @@ static struct page *follow_pmd_mask(stru
pmdval = READ_ONCE(*pmd);
if (pmd_none(pmdval))
return no_page_table(vma, flags);
-retry:
- if (!pmd_present(pmdval)) {
- /*
- * Should never reach here, if thp migration is not supported;
- * Otherwise, it must be a thp migration entry.
- */
- VM_BUG_ON(!thp_migration_supported() ||
- !is_pmd_migration_entry(pmdval));
-
- if (likely(!(flags & FOLL_MIGRATION)))
- return no_page_table(vma, flags);
-
- pmd_migration_entry_wait(mm, pmd);
- pmdval = READ_ONCE(*pmd);
- /*
- * MADV_DONTNEED may convert the pmd to null because
- * mmap_lock is held in read mode
- */
- if (pmd_none(pmdval))
- return no_page_table(vma, flags);
- goto retry;
- }
+ if (!pmd_present(pmdval))
+ return no_page_table(vma, flags);
if (pmd_devmap(pmdval)) {
ptl = pmd_lock(mm, pmd);
page = follow_devmap_pmd(vma, address, pmd, flags, &ctx->pgmap);
@@ -703,18 +666,10 @@ retry:
if (pmd_protnone(pmdval) && !gup_can_follow_protnone(flags))
return no_page_table(vma, flags);
-retry_locked:
ptl = pmd_lock(mm, pmd);
- if (unlikely(pmd_none(*pmd))) {
- spin_unlock(ptl);
- return no_page_table(vma, flags);
- }
if (unlikely(!pmd_present(*pmd))) {
spin_unlock(ptl);
- if (likely(!(flags & FOLL_MIGRATION)))
- return no_page_table(vma, flags);
- pmd_migration_entry_wait(mm, pmd);
- goto retry_locked;
+ return no_page_table(vma, flags);
}
if (unlikely(!pmd_trans_huge(*pmd))) {
spin_unlock(ptl);
_
Patches currently in -mm which might be from david@xxxxxxxxxx are
