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=-9.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 31489C43461 for ; Fri, 11 Sep 2020 10:36:03 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id B7D8F208FE for ; Fri, 11 Sep 2020 10:36:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="iq0J1u0I" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B7D8F208FE Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 51ED76B0074; Fri, 11 Sep 2020 06:36:02 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4A8BC8E0001; Fri, 11 Sep 2020 06:36:02 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 36FB16B007B; Fri, 11 Sep 2020 06:36:02 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0234.hostedemail.com [216.40.44.234]) by kanga.kvack.org (Postfix) with ESMTP id 1A7316B0074 for ; Fri, 11 Sep 2020 06:36:02 -0400 (EDT) Received: from smtpin15.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id CF151181AEF1F for ; Fri, 11 Sep 2020 10:36:01 +0000 (UTC) X-FDA: 77250425322.15.book53_5517369270ee Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin15.hostedemail.com (Postfix) with ESMTP id 9E0CA1814B0C1 for ; Fri, 11 Sep 2020 10:36:01 +0000 (UTC) X-HE-Tag: book53_5517369270ee X-Filterd-Recvd-Size: 10078 Received: from us-smtp-1.mimecast.com (us-smtp-delivery-1.mimecast.com [205.139.110.120]) by imf33.hostedemail.com (Postfix) with ESMTP for ; Fri, 11 Sep 2020 10:36:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1599820560; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=BnrxSoOh/uq5q7BWXjNOPypcyuPGVWf3LbFO26fAERU=; b=iq0J1u0Iwluu+vEPnD3MnUzM0tnMm5XXtjzD99YbcHVAaJU/62qZqbeg05BtS99mBnxd9k yuK5+Sngqwxud7ktYC/qVC5ix1PJKEOPF7YrTvKAkSuBlnWqIilKzIbJdnz8MPlVTsE2mz xJIGHEi28z5ImOmLEIYG9jmWKp1L7Yo= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-440-WJjyTmDAPdGgDjVu_RQJAw-1; Fri, 11 Sep 2020 06:35:56 -0400 X-MC-Unique: WJjyTmDAPdGgDjVu_RQJAw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 878F010082E6; Fri, 11 Sep 2020 10:35:53 +0000 (UTC) Received: from t480s.redhat.com (ovpn-113-186.ams2.redhat.com [10.36.113.186]) by smtp.corp.redhat.com (Postfix) with ESMTP id B35EB81C44; Fri, 11 Sep 2020 10:35:45 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: virtualization@lists.linux-foundation.org, linux-mm@kvack.org, linux-hyperv@vger.kernel.org, xen-devel@lists.xenproject.org, linux-acpi@vger.kernel.org, linux-nvdimm@lists.01.org, linux-s390@vger.kernel.org, Andrew Morton , David Hildenbrand , Pankaj Gupta , Michal Hocko , Dan Williams , Jason Gunthorpe , Kees Cook , Ard Biesheuvel , Thomas Gleixner , "K. Y. Srinivasan" , Haiyang Zhang , Stephen Hemminger , Wei Liu , Boris Ostrovsky , Juergen Gross , Stefano Stabellini , =?UTF-8?q?Roger=20Pau=20Monn=C3=A9?= , Julien Grall , Baoquan He , Wei Yang Subject: [PATCH v4 5/8] mm/memory_hotplug: MEMHP_MERGE_RESOURCE to specify merging of System RAM resources Date: Fri, 11 Sep 2020 12:34:56 +0200 Message-Id: <20200911103459.10306-6-david@redhat.com> In-Reply-To: <20200911103459.10306-1-david@redhat.com> References: <20200911103459.10306-1-david@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Rspamd-Queue-Id: 9E0CA1814B0C1 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam03 Content-Transfer-Encoding: quoted-printable 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: Some add_memory*() users add memory in small, contiguous memory blocks. Examples include virtio-mem, hyper-v balloon, and the XEN balloon. This can quickly result in a lot of memory resources, whereby the actual resource boundaries are not of interest (e.g., it might be relevant for DIMMs, exposed via /proc/iomem to user space). We really want to merge added resources in this scenario where possible. Let's provide a flag (MEMHP_MERGE_RESOURCE) to specify that a resource either created within add_memory*() or passed via add_memory_resource() shall be marked mergeable and merged with applicable siblings. To implement that, we need a kernel/resource interface to mark selected System RAM resources mergeable (IORESOURCE_SYSRAM_MERGEABLE) and trigger merging. Note: We really want to merge after the whole operation succeeded, not directly when adding a resource to the resource tree (it would break add_memory_resource() and require splitting resources again when the operation failed - e.g., due to -ENOMEM). Reviewed-by: Pankaj Gupta Cc: Andrew Morton Cc: Michal Hocko Cc: Dan Williams Cc: Jason Gunthorpe Cc: Kees Cook Cc: Ard Biesheuvel Cc: Thomas Gleixner Cc: "K. Y. Srinivasan" Cc: Haiyang Zhang Cc: Stephen Hemminger Cc: Wei Liu Cc: Boris Ostrovsky Cc: Juergen Gross Cc: Stefano Stabellini Cc: Roger Pau Monn=C3=A9 Cc: Julien Grall Cc: Pankaj Gupta Cc: Baoquan He Cc: Wei Yang Signed-off-by: David Hildenbrand --- include/linux/ioport.h | 4 +++ include/linux/memory_hotplug.h | 7 ++++ kernel/resource.c | 60 ++++++++++++++++++++++++++++++++++ mm/memory_hotplug.c | 7 ++++ 4 files changed, 78 insertions(+) diff --git a/include/linux/ioport.h b/include/linux/ioport.h index d7620d7c941a0..7e61389dcb017 100644 --- a/include/linux/ioport.h +++ b/include/linux/ioport.h @@ -60,6 +60,7 @@ struct resource { =20 /* IORESOURCE_SYSRAM specific bits. */ #define IORESOURCE_SYSRAM_DRIVER_MANAGED 0x02000000 /* Always detected v= ia a driver. */ +#define IORESOURCE_SYSRAM_MERGEABLE 0x04000000 /* Resource can be merge= d. */ =20 #define IORESOURCE_EXCLUSIVE 0x08000000 /* Userland may not map this res= ource */ =20 @@ -253,6 +254,9 @@ extern void __release_region(struct resource *, resou= rce_size_t, extern void release_mem_region_adjustable(struct resource *, resource_si= ze_t, resource_size_t); #endif +#ifdef CONFIG_MEMORY_HOTPLUG +extern void merge_system_ram_resource(struct resource *res); +#endif =20 /* Wrappers for managed devices */ struct device; diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplu= g.h index 33eb80fdba22f..d65c6fdc5cfc3 100644 --- a/include/linux/memory_hotplug.h +++ b/include/linux/memory_hotplug.h @@ -62,6 +62,13 @@ typedef int __bitwise mhp_t; =20 /* No special request */ #define MHP_NONE ((__force mhp_t)0) +/* + * Allow merging of the added System RAM resource with adjacent, + * mergeable resources. After a successful call to add_memory_resource() + * with this flag set, the resource pointer must no longer be used as it + * might be stale, or the resource might have changed. + */ +#define MEMHP_MERGE_RESOURCE ((__force mhp_t)BIT(0)) =20 /* * Extended parameters for memory hotplug: diff --git a/kernel/resource.c b/kernel/resource.c index 36b3552210120..7a91b935f4c20 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -1363,6 +1363,66 @@ void release_mem_region_adjustable(struct resource= *parent, } #endif /* CONFIG_MEMORY_HOTREMOVE */ =20 +#ifdef CONFIG_MEMORY_HOTPLUG +static bool system_ram_resources_mergeable(struct resource *r1, + struct resource *r2) +{ + /* We assume either r1 or r2 is IORESOURCE_SYSRAM_MERGEABLE. */ + return r1->flags =3D=3D r2->flags && r1->end + 1 =3D=3D r2->start && + r1->name =3D=3D r2->name && r1->desc =3D=3D r2->desc && + !r1->child && !r2->child; +} + +/* + * merge_system_ram_resource - mark the System RAM resource mergeable an= d try to + * merge it with adjacent, mergeable resources + * @res: resource descriptor + * + * This interface is intended for memory hotplug, whereby lots of contig= uous + * system ram resources are added (e.g., via add_memory*()) by a driver,= and + * the actual resource boundaries are not of interest (e.g., it might be + * relevant for DIMMs). Only resources that are marked mergeable, that h= ave the + * same parent, and that don't have any children are considered. All mer= geable + * resources must be immutable during the request. + * + * Note: + * - The caller has to make sure that no pointers to resources that are + * marked mergeable are used anymore after this call - the resource mi= ght + * be freed and the pointer might be stale! + * - release_mem_region_adjustable() will split on demand on memory hotu= nplug + */ +void merge_system_ram_resource(struct resource *res) +{ + const unsigned long flags =3D IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; + struct resource *cur; + + if (WARN_ON_ONCE((res->flags & flags) !=3D flags)) + return; + + write_lock(&resource_lock); + res->flags |=3D IORESOURCE_SYSRAM_MERGEABLE; + + /* Try to merge with next item in the list. */ + cur =3D res->sibling; + if (cur && system_ram_resources_mergeable(res, cur)) { + res->end =3D cur->end; + res->sibling =3D cur->sibling; + free_resource(cur); + } + + /* Try to merge with previous item in the list. */ + cur =3D res->parent->child; + while (cur && cur->sibling !=3D res) + cur =3D cur->sibling; + if (cur && system_ram_resources_mergeable(cur, res)) { + cur->end =3D res->end; + cur->sibling =3D res->sibling; + free_resource(res); + } + write_unlock(&resource_lock); +} +#endif /* CONFIG_MEMORY_HOTPLUG */ + /* * Managed region resource */ diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 8f0bd7c9a63a5..553c718226b3e 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1102,6 +1102,13 @@ int __ref add_memory_resource(int nid, struct reso= urce *res, mhp_t mhp_flags) /* device_online() will take the lock when calling online_pages() */ mem_hotplug_done(); =20 + /* + * In case we're allowed to merge the resource, flag it and trigger + * merging now that adding succeeded. + */ + if (mhp_flags & MEMHP_MERGE_RESOURCE) + merge_system_ram_resource(res); + /* online pages if requested */ if (memhp_default_online_type !=3D MMOP_OFFLINE) walk_memory_blocks(start, size, NULL, online_memory_block); --=20 2.26.2