The patch titled
Subject: mm: change folio_lock_or_retry to use vm_fault directly
has been added to the -mm mm-unstable branch. Its filename is
mm-change-folio_lock_or_retry-to-use-vm_fault-directly.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-change-folio_lock_or_retry-to-use-vm_fault-directly.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Subject: mm: change folio_lock_or_retry to use vm_fault directly
Date: Fri, 30 Jun 2023 14:19:55 -0700
Change folio_lock_or_retry to accept vm_fault struct and return the
vm_fault_t directly.
Link: https://lkml.kernel.org/r/20230630211957.1341547-5-surenb@xxxxxxxxxx
Signed-off-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Suggested-by: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Acked-by: Peter Xu <peterx@xxxxxxxxxx>
Cc: Alistair Popple <apopple@xxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Christian Brauner <brauner@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: David Howells <dhowells@xxxxxxxxxx>
Cc: Davidlohr Bueso <dave@xxxxxxxxxxxx>
Cc: Hillf Danton <hdanton@xxxxxxxx>
Cc: "Huang, Ying" <ying.huang@xxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Josef Bacik <josef@xxxxxxxxxxxxxx>
Cc: Laurent Dufour <ldufour@xxxxxxxxxxxxx>
Cc: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Cc: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Michel Lespinasse <michel@xxxxxxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
Cc: Punit Agrawal <punit.agrawal@xxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Yu Zhao <yuzhao@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/pagemap.h | 11 ++++++-----
mm/filemap.c | 22 ++++++++++++----------
mm/memory.c | 14 ++++++--------
3 files changed, 24 insertions(+), 23 deletions(-)
--- a/include/linux/pagemap.h~mm-change-folio_lock_or_retry-to-use-vm_fault-directly
+++ a/include/linux/pagemap.h
@@ -900,8 +900,7 @@ static inline bool wake_page_match(struc
void __folio_lock(struct folio *folio);
int __folio_lock_killable(struct folio *folio);
-bool __folio_lock_or_retry(struct folio *folio, struct mm_struct *mm,
- unsigned int flags);
+vm_fault_t __folio_lock_or_retry(struct folio *folio, struct vm_fault *vmf);
void unlock_page(struct page *page);
void folio_unlock(struct folio *folio);
@@ -1005,11 +1004,13 @@ static inline int folio_lock_killable(st
* Return value and mmap_lock implications depend on flags; see
* __folio_lock_or_retry().
*/
-static inline bool folio_lock_or_retry(struct folio *folio,
- struct mm_struct *mm, unsigned int flags)
+static inline vm_fault_t folio_lock_or_retry(struct folio *folio,
+ struct vm_fault *vmf)
{
might_sleep();
- return folio_trylock(folio) || __folio_lock_or_retry(folio, mm, flags);
+ if (!folio_trylock(folio))
+ return __folio_lock_or_retry(folio, vmf);
+ return 0;
}
/*
--- a/mm/filemap.c~mm-change-folio_lock_or_retry-to-use-vm_fault-directly
+++ a/mm/filemap.c
@@ -1669,32 +1669,34 @@ static int __folio_lock_async(struct fol
/*
* Return values:
- * true - folio is locked; mmap_lock is still held.
- * false - folio is not locked.
+ * 0 - folio is locked.
+ * non-zero - folio is not locked.
* mmap_lock has been released (mmap_read_unlock(), unless flags had both
* FAULT_FLAG_ALLOW_RETRY and FAULT_FLAG_RETRY_NOWAIT set, in
* which case mmap_lock is still held.
*
- * If neither ALLOW_RETRY nor KILLABLE are set, will always return true
+ * If neither ALLOW_RETRY nor KILLABLE are set, will always return 0
* with the folio locked and the mmap_lock unperturbed.
*/
-bool __folio_lock_or_retry(struct folio *folio, struct mm_struct *mm,
- unsigned int flags)
+vm_fault_t __folio_lock_or_retry(struct folio *folio, struct vm_fault *vmf)
{
+ struct mm_struct *mm = vmf->vma->vm_mm;
+ unsigned int flags = vmf->flags;
+
if (fault_flag_allow_retry_first(flags)) {
/*
* CAUTION! In this case, mmap_lock is not released
- * even though return 0.
+ * even though return VM_FAULT_RETRY.
*/
if (flags & FAULT_FLAG_RETRY_NOWAIT)
- return false;
+ return VM_FAULT_RETRY;
mmap_read_unlock(mm);
if (flags & FAULT_FLAG_KILLABLE)
folio_wait_locked_killable(folio);
else
folio_wait_locked(folio);
- return false;
+ return VM_FAULT_RETRY;
}
if (flags & FAULT_FLAG_KILLABLE) {
bool ret;
@@ -1702,13 +1704,13 @@ bool __folio_lock_or_retry(struct folio
ret = __folio_lock_killable(folio);
if (ret) {
mmap_read_unlock(mm);
- return false;
+ return VM_FAULT_RETRY;
}
} else {
__folio_lock(folio);
}
- return true;
+ return 0;
}
/**
--- a/mm/memory.c~mm-change-folio_lock_or_retry-to-use-vm_fault-directly
+++ a/mm/memory.c
@@ -3585,6 +3585,7 @@ static vm_fault_t remove_device_exclusiv
struct folio *folio = page_folio(vmf->page);
struct vm_area_struct *vma = vmf->vma;
struct mmu_notifier_range range;
+ vm_fault_t ret;
/*
* We need a reference to lock the folio because we don't hold
@@ -3597,9 +3598,10 @@ static vm_fault_t remove_device_exclusiv
if (!folio_try_get(folio))
return 0;
- if (!folio_lock_or_retry(folio, vma->vm_mm, vmf->flags)) {
+ ret = folio_lock_or_retry(folio, vmf);
+ if (ret) {
folio_put(folio);
- return VM_FAULT_RETRY;
+ return ret;
}
mmu_notifier_range_init_owner(&range, MMU_NOTIFY_EXCLUSIVE, 0,
vma->vm_mm, vmf->address & PAGE_MASK,
@@ -3724,7 +3726,6 @@ vm_fault_t do_swap_page(struct vm_fault
bool exclusive = false;
swp_entry_t entry;
pte_t pte;
- int locked;
vm_fault_t ret = 0;
void *shadow = NULL;
@@ -3847,12 +3848,9 @@ vm_fault_t do_swap_page(struct vm_fault
goto out_release;
}
- locked = folio_lock_or_retry(folio, vma->vm_mm, vmf->flags);
-
- if (!locked) {
- ret |= VM_FAULT_RETRY;
+ ret |= folio_lock_or_retry(folio, vmf);
+ if (ret & VM_FAULT_RETRY)
goto out_release;
- }
if (swapcache) {
/*
_
Patches currently in -mm which might be from surenb@xxxxxxxxxx are
swap-remove-remnants-of-polling-from-read_swap_cache_async.patch
mm-add-missing-vm_fault_result_trace-name-for-vm_fault_completed.patch
mm-drop-per-vma-lock-when-returning-vm_fault_retry-or-vm_fault_completed.patch
mm-change-folio_lock_or_retry-to-use-vm_fault-directly.patch
mm-handle-swap-page-faults-under-per-vma-lock.patch
mm-handle-userfaults-under-vma-lock.patch
