| Message ID | 20210511214735.1836149-23-willy@infradead.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Memory folios | expand |
On 5/11/21 11:47 PM, Matthew Wilcox (Oracle) wrote: > Convert __lock_page_or_retry() to __folio_lock_or_retry(). This actually > saves 4 bytes in the only caller of lock_page_or_retry() (due to better > register allocation) and saves the 20 byte cost of calling page_folio() > in __folio_lock_or_retry() for a total saving of 24 bytes. > > Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> > Reviewed-by: Christoph Hellwig <hch@lst.de> > Acked-by: Jeff Layton <jlayton@kernel.org> > --- > include/linux/pagemap.h | 9 ++++++--- > mm/filemap.c | 10 ++++------ > mm/memory.c | 8 ++++---- > 3 files changed, 14 insertions(+), 13 deletions(-) > > diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h > index 41224e4ca8cc..21e394964288 100644 > --- a/include/linux/pagemap.h > +++ b/include/linux/pagemap.h > @@ -640,7 +640,7 @@ static inline bool wake_page_match(struct wait_page_queue *wait_page, > > void __folio_lock(struct folio *folio); > int __folio_lock_killable(struct folio *folio); > -extern int __lock_page_or_retry(struct page *page, struct mm_struct *mm, > +int __folio_lock_or_retry(struct folio *folio, struct mm_struct *mm, > unsigned int flags); > void unlock_page(struct page *page); > void folio_unlock(struct folio *folio); > @@ -701,13 +701,16 @@ static inline int lock_page_killable(struct page *page) > * caller indicated that it can handle a retry. > * > * Return value and mmap_lock implications depend on flags; see > - * __lock_page_or_retry(). > + * __folio_lock_or_retry(). > */ > static inline int lock_page_or_retry(struct page *page, struct mm_struct *mm, > unsigned int flags) > { > + struct folio *folio; > might_sleep(); > - return trylock_page(page) || __lock_page_or_retry(page, mm, flags); > + > + folio = page_folio(page); > + return folio_trylock(folio) || __folio_lock_or_retry(folio, mm, flags); > } > > /* > diff --git a/mm/filemap.c b/mm/filemap.c > index 67334eb3fd94..28bf50041671 100644 > --- a/mm/filemap.c > +++ b/mm/filemap.c > @@ -1623,20 +1623,18 @@ static int __folio_lock_async(struct folio *folio, struct wait_page_queue *wait) > > /* > * Return values: > - * 1 - page is locked; mmap_lock is still held. > - * 0 - page is not locked. > + * 1 - folio is locked; mmap_lock is still held. > + * 0 - 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 1 > - * with the page locked and the mmap_lock unperturbed. > + * with the folio locked and the mmap_lock unperturbed. > */ > -int __lock_page_or_retry(struct page *page, struct mm_struct *mm, > +int __folio_lock_or_retry(struct folio *folio, struct mm_struct *mm, > unsigned int flags) > { > - struct folio *folio = page_folio(page); > - > if (fault_flag_allow_retry_first(flags)) { > /* > * CAUTION! In this case, mmap_lock is not released A bit later in this branch, 'page' is accessed, but it no longer exists. And thus as expected, it doesn't compile. Assuming it's fixed later, but bisectability etc... > diff --git a/mm/memory.c b/mm/memory.c > index 86ba6c1f6821..fc3f50d0702c 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -4065,7 +4065,7 @@ static vm_fault_t do_shared_fault(struct vm_fault *vmf) > * We enter with non-exclusive mmap_lock (to exclude vma changes, > * but allow concurrent faults). > * The mmap_lock may have been released depending on flags and our > - * return value. See filemap_fault() and __lock_page_or_retry(). > + * return value. See filemap_fault() and __folio_lock_or_retry(). > * If mmap_lock is released, vma may become invalid (for example > * by other thread calling munmap()). > */ > @@ -4307,7 +4307,7 @@ static vm_fault_t wp_huge_pud(struct vm_fault *vmf, pud_t orig_pud) > * concurrent faults). > * > * The mmap_lock may have been released depending on flags and our return value. > - * See filemap_fault() and __lock_page_or_retry(). > + * See filemap_fault() and __folio_lock_or_retry(). > */ > static vm_fault_t handle_pte_fault(struct vm_fault *vmf) > { > @@ -4411,7 +4411,7 @@ static vm_fault_t handle_pte_fault(struct vm_fault *vmf) > * By the time we get here, we already hold the mm semaphore > * > * The mmap_lock may have been released depending on flags and our > - * return value. See filemap_fault() and __lock_page_or_retry(). > + * return value. See filemap_fault() and __folio_lock_or_retry(). > */ > static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma, > unsigned long address, unsigned int flags) > @@ -4567,7 +4567,7 @@ static inline void mm_account_fault(struct pt_regs *regs, > * By the time we get here, we already hold the mm semaphore > * > * The mmap_lock may have been released depending on flags and our > - * return value. See filemap_fault() and __lock_page_or_retry(). > + * return value. See filemap_fault() and __folio_lock_or_retry(). > */ > vm_fault_t handle_mm_fault(struct vm_area_struct *vma, unsigned long address, > unsigned int flags, struct pt_regs *regs) >
On 5/18/21 12:38 PM, Vlastimil Babka wrote: >> --- a/mm/filemap.c >> +++ b/mm/filemap.c >> @@ -1623,20 +1623,18 @@ static int __folio_lock_async(struct folio *folio, struct wait_page_queue *wait) >> >> /* >> * Return values: >> - * 1 - page is locked; mmap_lock is still held. >> - * 0 - page is not locked. >> + * 1 - folio is locked; mmap_lock is still held. >> + * 0 - 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 1 >> - * with the page locked and the mmap_lock unperturbed. >> + * with the folio locked and the mmap_lock unperturbed. >> */ >> -int __lock_page_or_retry(struct page *page, struct mm_struct *mm, >> +int __folio_lock_or_retry(struct folio *folio, struct mm_struct *mm, >> unsigned int flags) >> { >> - struct folio *folio = page_folio(page); >> - >> if (fault_flag_allow_retry_first(flags)) { >> /* >> * CAUTION! In this case, mmap_lock is not released > > A bit later in this branch, 'page' is accessed, but it no longer exists. And > thus as expected, it doesn't compile. Assuming it's fixed later, but > bisectability etc... Also, the switch from 'page' to &folio->page in there should probably have been done already in "[PATCH v10 20/33] mm/filemap: Add folio_lock_killable", not in this patch?
On Tue, May 18, 2021 at 12:38:46PM +0200, Vlastimil Babka wrote: > > -int __lock_page_or_retry(struct page *page, struct mm_struct *mm, > > +int __folio_lock_or_retry(struct folio *folio, struct mm_struct *mm, > > unsigned int flags) > > { > > - struct folio *folio = page_folio(page); > > - > > if (fault_flag_allow_retry_first(flags)) { > > /* > > * CAUTION! In this case, mmap_lock is not released > > A bit later in this branch, 'page' is accessed, but it no longer exists. And > thus as expected, it doesn't compile. Assuming it's fixed later, but > bisectability etc... Oops. Thanks for catching that; I've reordered this patch and the folio_wait_locked() patch, which makes the entire problem go away.
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 41224e4ca8cc..21e394964288 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -640,7 +640,7 @@ static inline bool wake_page_match(struct wait_page_queue *wait_page, void __folio_lock(struct folio *folio); int __folio_lock_killable(struct folio *folio); -extern int __lock_page_or_retry(struct page *page, struct mm_struct *mm, +int __folio_lock_or_retry(struct folio *folio, struct mm_struct *mm, unsigned int flags); void unlock_page(struct page *page); void folio_unlock(struct folio *folio); @@ -701,13 +701,16 @@ static inline int lock_page_killable(struct page *page) * caller indicated that it can handle a retry. * * Return value and mmap_lock implications depend on flags; see - * __lock_page_or_retry(). + * __folio_lock_or_retry(). */ static inline int lock_page_or_retry(struct page *page, struct mm_struct *mm, unsigned int flags) { + struct folio *folio; might_sleep(); - return trylock_page(page) || __lock_page_or_retry(page, mm, flags); + + folio = page_folio(page); + return folio_trylock(folio) || __folio_lock_or_retry(folio, mm, flags); } /* diff --git a/mm/filemap.c b/mm/filemap.c index 67334eb3fd94..28bf50041671 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1623,20 +1623,18 @@ static int __folio_lock_async(struct folio *folio, struct wait_page_queue *wait) /* * Return values: - * 1 - page is locked; mmap_lock is still held. - * 0 - page is not locked. + * 1 - folio is locked; mmap_lock is still held. + * 0 - 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 1 - * with the page locked and the mmap_lock unperturbed. + * with the folio locked and the mmap_lock unperturbed. */ -int __lock_page_or_retry(struct page *page, struct mm_struct *mm, +int __folio_lock_or_retry(struct folio *folio, struct mm_struct *mm, unsigned int flags) { - struct folio *folio = page_folio(page); - if (fault_flag_allow_retry_first(flags)) { /* * CAUTION! In this case, mmap_lock is not released diff --git a/mm/memory.c b/mm/memory.c index 86ba6c1f6821..fc3f50d0702c 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -4065,7 +4065,7 @@ static vm_fault_t do_shared_fault(struct vm_fault *vmf) * We enter with non-exclusive mmap_lock (to exclude vma changes, * but allow concurrent faults). * The mmap_lock may have been released depending on flags and our - * return value. See filemap_fault() and __lock_page_or_retry(). + * return value. See filemap_fault() and __folio_lock_or_retry(). * If mmap_lock is released, vma may become invalid (for example * by other thread calling munmap()). */ @@ -4307,7 +4307,7 @@ static vm_fault_t wp_huge_pud(struct vm_fault *vmf, pud_t orig_pud) * concurrent faults). * * The mmap_lock may have been released depending on flags and our return value. - * See filemap_fault() and __lock_page_or_retry(). + * See filemap_fault() and __folio_lock_or_retry(). */ static vm_fault_t handle_pte_fault(struct vm_fault *vmf) { @@ -4411,7 +4411,7 @@ static vm_fault_t handle_pte_fault(struct vm_fault *vmf) * By the time we get here, we already hold the mm semaphore * * The mmap_lock may have been released depending on flags and our - * return value. See filemap_fault() and __lock_page_or_retry(). + * return value. See filemap_fault() and __folio_lock_or_retry(). */ static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma, unsigned long address, unsigned int flags) @@ -4567,7 +4567,7 @@ static inline void mm_account_fault(struct pt_regs *regs, * By the time we get here, we already hold the mm semaphore * * The mmap_lock may have been released depending on flags and our - * return value. See filemap_fault() and __lock_page_or_retry(). + * return value. See filemap_fault() and __folio_lock_or_retry(). */ vm_fault_t handle_mm_fault(struct vm_area_struct *vma, unsigned long address, unsigned int flags, struct pt_regs *regs)