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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 134B9C433F5 for ; Wed, 16 Mar 2022 10:43:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355190AbiCPKod (ORCPT ); Wed, 16 Mar 2022 06:44:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42814 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238075AbiCPKoc (ORCPT ); Wed, 16 Mar 2022 06:44:32 -0400 Received: from out30-130.freemail.mail.aliyun.com (out30-130.freemail.mail.aliyun.com [115.124.30.130]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9B43913DF9; Wed, 16 Mar 2022 03:43:18 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R151e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04407;MF=xiaoguang.wang@linux.alibaba.com;NM=1;PH=DS;RN=3;SR=0;TI=SMTPD_---0V7Mc5x4_1647427395; Received: from 30.225.28.170(mailfrom:xiaoguang.wang@linux.alibaba.com fp:SMTPD_---0V7Mc5x4_1647427395) by smtp.aliyun-inc.com(127.0.0.1); Wed, 16 Mar 2022 18:43:16 +0800 Message-ID: Date: Wed, 16 Mar 2022 18:43:15 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Subject: Re: [PATCH 2/2] scsi: target: tcmu: Use address_space->invalidate_lock Content-Language: en-US From: Xiaoguang Wang To: linux-scsi@vger.kernel.org, target-devel@vger.kernel.org Cc: bostroesser@gmail.com References: <20220311132206.24515-1-xiaoguang.wang@linux.alibaba.com> <20220311132206.24515-2-xiaoguang.wang@linux.alibaba.com> In-Reply-To: <20220311132206.24515-2-xiaoguang.wang@linux.alibaba.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org hello, Gentle ping. Regards, Xiaoguang Wang > Currently tcmu_vma_fault() uses udev->cmdr_lock to avoid concurrent > find_free_blocks(), which unmaps idle pages and truncates them. This > work is really like many filesystem's truncate operations, but they > use address_space->invalidate_lock to protect race. > > This patch replaces cmdr_lock with address_space->invalidate_lock in > tcmu fault procedure, which will also make page-fault have concurrency. > > Signed-off-by: Xiaoguang Wang > --- > drivers/target/target_core_user.c | 13 +++++++++---- > 1 file changed, 9 insertions(+), 4 deletions(-) > > diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c > index 06a5c4086551..e0a62623ccd7 100644 > --- a/drivers/target/target_core_user.c > +++ b/drivers/target/target_core_user.c > @@ -1815,13 +1815,14 @@ static int tcmu_find_mem_index(struct vm_area_struct *vma) > > static struct page *tcmu_try_get_data_page(struct tcmu_dev *udev, uint32_t dpi) > { > + struct address_space *mapping = udev->inode->i_mapping; > struct page *page; > > - mutex_lock(&udev->cmdr_lock); > + filemap_invalidate_lock_shared(mapping); > page = xa_load(&udev->data_pages, dpi); > if (likely(page)) { > get_page(page); > - mutex_unlock(&udev->cmdr_lock); > + filemap_invalidate_unlock_shared(mapping); > return page; > } > > @@ -1831,7 +1832,7 @@ static struct page *tcmu_try_get_data_page(struct tcmu_dev *udev, uint32_t dpi) > */ > pr_err("Invalid addr to data page mapping (dpi %u) on device %s\n", > dpi, udev->name); > - mutex_unlock(&udev->cmdr_lock); > + filemap_invalidate_unlock_shared(mapping); > > return NULL; > } > @@ -3111,6 +3112,7 @@ static void find_free_blocks(void) > loff_t off; > u32 pages_freed, total_pages_freed = 0; > u32 start, end, block, total_blocks_freed = 0; > + struct address_space *mapping; > > if (atomic_read(&global_page_count) <= tcmu_global_max_pages) > return; > @@ -3134,6 +3136,7 @@ static void find_free_blocks(void) > continue; > } > > + mapping = udev->inode->i_mapping; > end = udev->dbi_max + 1; > block = find_last_bit(udev->data_bitmap, end); > if (block == udev->dbi_max) { > @@ -3152,12 +3155,14 @@ static void find_free_blocks(void) > udev->dbi_max = block; > } > > + filemap_invalidate_lock(mapping); > /* Here will truncate the data area from off */ > off = udev->data_off + (loff_t)start * udev->data_blk_size; > - unmap_mapping_range(udev->inode->i_mapping, off, 0, 1); > + unmap_mapping_range(mapping, off, 0, 1); > > /* Release the block pages */ > pages_freed = tcmu_blocks_release(udev, start, end - 1); > + filemap_invalidate_unlock(mapping); > mutex_unlock(&udev->cmdr_lock); > > total_pages_freed += pages_freed;