From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 539DDC43461 for ; Tue, 18 May 2021 10:38:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2AAE86124C for ; Tue, 18 May 2021 10:38:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242722AbhERKkI (ORCPT ); Tue, 18 May 2021 06:40:08 -0400 Received: from mx2.suse.de ([195.135.220.15]:49820 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242136AbhERKkG (ORCPT ); Tue, 18 May 2021 06:40:06 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 48F38AF37; Tue, 18 May 2021 10:38:47 +0000 (UTC) Subject: Re: [PATCH v10 22/33] mm/filemap: Add __folio_lock_or_retry To: "Matthew Wilcox (Oracle)" , akpm@linux-foundation.org Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Christoph Hellwig , Jeff Layton References: <20210511214735.1836149-1-willy@infradead.org> <20210511214735.1836149-23-willy@infradead.org> From: Vlastimil Babka Message-ID: <76184de4-4ab9-0f04-ab37-8637f4b22566@suse.cz> Date: Tue, 18 May 2021 12:38:46 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: <20210511214735.1836149-23-willy@infradead.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org 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) > Reviewed-by: Christoph Hellwig > Acked-by: Jeff Layton > --- > 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) >