From patchwork Thu Nov 14 08:20:13 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Dan Williams X-Patchwork-Id: 11243223 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id EAD43930 for ; Thu, 14 Nov 2019 08:34:33 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id B59402071B for ; Thu, 14 Nov 2019 08:34:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B59402071B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id D58486B0003; Thu, 14 Nov 2019 03:34:32 -0500 (EST) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id D07CC6B0005; Thu, 14 Nov 2019 03:34:32 -0500 (EST) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C1E986B0006; Thu, 14 Nov 2019 03:34:32 -0500 (EST) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0076.hostedemail.com [216.40.44.76]) by kanga.kvack.org (Postfix) with ESMTP id AC8E06B0003 for ; Thu, 14 Nov 2019 03:34:32 -0500 (EST) Received: from smtpin11.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with SMTP id 44BA98249980 for ; Thu, 14 Nov 2019 08:34:32 +0000 (UTC) X-FDA: 76154221584.11.skin81_449b8e269f35b X-Spam-Summary: 1,0,0,,d41d8cd98f00b204,dan.j.williams@intel.com,:jhubbard@nvidia.com:jack@suse.cz:hch@lst.de:ira.weiny@intel.com:jglisse@redhat.com:linux-nvdimm@lists.01.org:linux-kernel@vger.kernel.org::dan.j.williams@intel.com,RULES_HIT:30054:30064:30090,0,RBL:192.55.52.88:@intel.com:.lbl8.mailshell.net-62.18.0.100 64.95.201.95,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:ft,MSBL:0,DNSBL:none,Custom_rules:0:0:0,LFtime:24,LUA_SUMMARY:none X-HE-Tag: skin81_449b8e269f35b X-Filterd-Recvd-Size: 6720 Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by imf27.hostedemail.com (Postfix) with ESMTP for ; Thu, 14 Nov 2019 08:34:31 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 14 Nov 2019 00:34:29 -0800 X-IronPort-AV: E=Sophos;i="5.68,302,1569308400"; d="scan'208";a="208060570" Received: from dwillia2-desk3.jf.intel.com (HELO dwillia2-desk3.amr.corp.intel.com) ([10.54.39.16]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 14 Nov 2019 00:34:29 -0800 Subject: [PATCH v2] mm: Cleanup __put_devmap_managed_page() vs ->page_free() From: Dan Williams To: jhubbard@nvidia.com Cc: Jan Kara , Christoph Hellwig , Ira Weiny , =?utf-8?b?SsOpcsO0bWU=?= Glisse , linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Date: Thu, 14 Nov 2019 00:20:13 -0800 Message-ID: <157371938291.3055029.12105459405251950438.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.18-3-g996c MIME-Version: 1.0 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: After the removal of the device-public infrastructure there are only 2 ->page_free() call backs in the kernel. One of those is a device-private callback in the nouveau driver, the other is a generic wakeup needed in the DAX case. In the hopes that all ->page_free() callbacks can be migrated to common core kernel functionality, move the device-private specific actions in __put_devmap_managed_page() under the is_device_private_page() conditional, including the ->page_free() callback. For the other page types just open-code the generic wakeup. Yes, the wakeup is only needed in the MEMORY_DEVICE_FSDAX case, but it does no harm in the MEMORY_DEVICE_DEVDAX and MEMORY_DEVICE_PCI_P2PDMA case. Cc: Jan Kara Cc: Christoph Hellwig Cc: Ira Weiny Cc: John Hubbard Reviewed-by: Jérôme Glisse Signed-off-by: Dan Williams --- Changes in v2: - Stop requiring pgmap->ops for fsdax (Christoph) - Clean up the indenting and organization in __put_devmap_managed_page(). (Christoph) drivers/nvdimm/pmem.c | 6 ---- mm/memremap.c | 77 ++++++++++++++++++++++++++----------------------- 2 files changed, 41 insertions(+), 42 deletions(-) diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c index f9f76f6ba07b..21db1ce8c0ae 100644 --- a/drivers/nvdimm/pmem.c +++ b/drivers/nvdimm/pmem.c @@ -338,13 +338,7 @@ static void pmem_release_disk(void *__pmem) put_disk(pmem->disk); } -static void pmem_pagemap_page_free(struct page *page) -{ - wake_up_var(&page->_refcount); -} - static const struct dev_pagemap_ops fsdax_pagemap_ops = { - .page_free = pmem_pagemap_page_free, .kill = pmem_pagemap_kill, .cleanup = pmem_pagemap_cleanup, }; diff --git a/mm/memremap.c b/mm/memremap.c index 022e78e68ea0..b52dc566efd2 100644 --- a/mm/memremap.c +++ b/mm/memremap.c @@ -27,7 +27,8 @@ static void devmap_managed_enable_put(void) static int devmap_managed_enable_get(struct dev_pagemap *pgmap) { - if (!pgmap->ops || !pgmap->ops->page_free) { + if (pgmap->type == MEMORY_DEVICE_PRIVATE && + (!pgmap->ops || !pgmap->ops->page_free)) { WARN(1, "Missing page_free method\n"); return -EINVAL; } @@ -444,44 +445,48 @@ void __put_devmap_managed_page(struct page *page) { int count = page_ref_dec_return(page); - /* - * If refcount is 1 then page is freed and refcount is stable as nobody - * holds a reference on the page. - */ - if (count == 1) { - /* Clear Active bit in case of parallel mark_page_accessed */ - __ClearPageActive(page); - __ClearPageWaiters(page); + if (count > 1) { + /* still busy */ + return; + } else if (count == 0) { + /* only triggered by the dev_pagemap shutdown path */ + __put_page(page); + return; + } else if (!is_device_private_page(page)) { + /* notify page idle for dax */ + wake_up_var(&page->_refcount); + return; + } - mem_cgroup_uncharge(page); + /* Clear Active bit in case of parallel mark_page_accessed */ + __ClearPageActive(page); + __ClearPageWaiters(page); - /* - * When a device_private page is freed, the page->mapping field - * may still contain a (stale) mapping value. For example, the - * lower bits of page->mapping may still identify the page as - * an anonymous page. Ultimately, this entire field is just - * stale and wrong, and it will cause errors if not cleared. - * One example is: - * - * migrate_vma_pages() - * migrate_vma_insert_page() - * page_add_new_anon_rmap() - * __page_set_anon_rmap() - * ...checks page->mapping, via PageAnon(page) call, - * and incorrectly concludes that the page is an - * anonymous page. Therefore, it incorrectly, - * silently fails to set up the new anon rmap. - * - * For other types of ZONE_DEVICE pages, migration is either - * handled differently or not done at all, so there is no need - * to clear page->mapping. - */ - if (is_device_private_page(page)) - page->mapping = NULL; + mem_cgroup_uncharge(page); - page->pgmap->ops->page_free(page); - } else if (!count) - __put_page(page); + /* + * When a device_private page is freed, the page->mapping field + * may still contain a (stale) mapping value. For example, the + * lower bits of page->mapping may still identify the page as an + * anonymous page. Ultimately, this entire field is just stale + * and wrong, and it will cause errors if not cleared. One + * example is: + * + * migrate_vma_pages() + * migrate_vma_insert_page() + * page_add_new_anon_rmap() + * __page_set_anon_rmap() + * ...checks page->mapping, via PageAnon(page) call, + * and incorrectly concludes that the page is an + * anonymous page. Therefore, it incorrectly, + * silently fails to set up the new anon rmap. + * + * For other types of ZONE_DEVICE pages, migration is either + * handled differently or not done at all, so there is no need + * to clear page->mapping. + */ + page->mapping = NULL; + page->pgmap->ops->page_free(page); } EXPORT_SYMBOL(__put_devmap_managed_page); #endif /* CONFIG_DEV_PAGEMAP_OPS */