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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 51A0FC169C4 for ; Mon, 11 Feb 2019 13:30:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1336221B1C for ; Mon, 11 Feb 2019 13:30:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727953AbfBKNaa (ORCPT ); Mon, 11 Feb 2019 08:30:30 -0500 Received: from mx1.redhat.com ([209.132.183.28]:39900 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727182AbfBKNa3 (ORCPT ); Mon, 11 Feb 2019 08:30:29 -0500 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D678358E33; Mon, 11 Feb 2019 13:30:28 +0000 (UTC) Received: from [10.18.17.32] (dhcp-17-32.bos.redhat.com [10.18.17.32]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 34BE66012B; Mon, 11 Feb 2019 13:30:05 +0000 (UTC) From: Nitesh Narayan Lal Subject: Re: [RFC PATCH 4/4] mm: Add merge page notifier To: "Michael S. Tsirkin" , Alexander Duyck Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, rkrcmar@redhat.com, alexander.h.duyck@linux.intel.com, x86@kernel.org, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, pbonzini@redhat.com, tglx@linutronix.de, akpm@linux-foundation.org References: <20190204181118.12095.38300.stgit@localhost.localdomain> <20190204181558.12095.83484.stgit@localhost.localdomain> <20190209195325-mutt-send-email-mst@kernel.org> Openpgp: preference=signencrypt Autocrypt: addr=nitesh@redhat.com; prefer-encrypt=mutual; keydata= mQINBFl4pQoBEADT/nXR2JOfsCjDgYmE2qonSGjkM1g8S6p9UWD+bf7YEAYYYzZsLtbilFTe z4nL4AV6VJmC7dBIlTi3Mj2eymD/2dkKP6UXlliWkq67feVg1KG+4UIp89lFW7v5Y8Muw3Fm uQbFvxyhN8n3tmhRe+ScWsndSBDxYOZgkbCSIfNPdZrHcnOLfA7xMJZeRCjqUpwhIjxQdFA7 n0s0KZ2cHIsemtBM8b2WXSQG9CjqAJHVkDhrBWKThDRF7k80oiJdEQlTEiVhaEDURXq+2XmG jpCnvRQDb28EJSsQlNEAzwzHMeplddfB0vCg9fRk/kOBMDBtGsTvNT9OYUZD+7jaf0gvBvBB lbKmmMMX7uJB+ejY7bnw6ePNrVPErWyfHzR5WYrIFUtgoR3LigKnw5apzc7UIV9G8uiIcZEn C+QJCK43jgnkPcSmwVPztcrkbC84g1K5v2Dxh9amXKLBA1/i+CAY8JWMTepsFohIFMXNLj+B RJoOcR4HGYXZ6CAJa3Glu3mCmYqHTOKwezJTAvmsCLd3W7WxOGF8BbBjVaPjcZfavOvkin0u DaFvhAmrzN6lL0msY17JCZo046z8oAqkyvEflFbC0S1R/POzehKrzQ1RFRD3/YzzlhmIowkM BpTqNBeHEzQAlIhQuyu1ugmQtfsYYq6FPmWMRfFPes/4JUU/PQARAQABtCVOaXRlc2ggTmFy YXlhbiBMYWwgPG5pbGFsQHJlZGhhdC5jb20+iQI9BBMBCAAnBQJZeKUKAhsjBQkJZgGABQsJ CAcCBhUICQoLAgQWAgMBAh4BAheAAAoJEKOGQNwGMqM56lEP/A2KMs/pu0URcVk/kqVwcBhU SnvB8DP3lDWDnmVrAkFEOnPX7GTbactQ41wF/xwjwmEmTzLrMRZpkqz2y9mV0hWHjqoXbOCS 6RwK3ri5e2ThIPoGxFLt6TrMHgCRwm8YuOSJ97o+uohCTN8pmQ86KMUrDNwMqRkeTRW9wWIQ EdDqW44VwelnyPwcmWHBNNb1Kd8j3xKlHtnS45vc6WuoKxYRBTQOwI/5uFpDZtZ1a5kq9Ak/ MOPDDZpd84rqd+IvgMw5z4a5QlkvOTpScD21G3gjmtTEtyfahltyDK/5i8IaQC3YiXJCrqxE r7/4JMZeOYiKpE9iZMtS90t4wBgbVTqAGH1nE/ifZVAUcCtycD0f3egX9CHe45Ad4fsF3edQ ESa5tZAogiA4Hc/yQpnnf43a3aQ67XPOJXxS0Qptzu4vfF9h7kTKYWSrVesOU3QKYbjEAf95 NewF9FhAlYqYrwIwnuAZ8TdXVDYt7Z3z506//sf6zoRwYIDA8RDqFGRuPMXUsoUnf/KKPrtR ceLcSUP/JCNiYbf1/QtW8S6Ca/4qJFXQHp0knqJPGmwuFHsarSdpvZQ9qpxD3FnuPyo64S2N Dfq8TAeifNp2pAmPY2PAHQ3nOmKgMG8Gn5QiORvMUGzSz8Lo31LW58NdBKbh6bci5+t/HE0H pnyVf5xhNC/FuQINBFl4pQoBEACr+MgxWHUP76oNNYjRiNDhaIVtnPRqxiZ9v4H5FPxJy9UD Bqr54rifr1E+K+yYNPt/Po43vVL2cAyfyI/LVLlhiY4yH6T1n+Di/hSkkviCaf13gczuvgz4 KVYLwojU8+naJUsiCJw01MjO3pg9GQ+47HgsnRjCdNmmHiUQqksMIfd8k3reO9SUNlEmDDNB XuSzkHjE5y/R/6p8uXaVpiKPfHoULjNRWaFc3d2JGmxJpBdpYnajoz61m7XJlgwl/B5Ql/6B dHGaX3VHxOZsfRfugwYF9CkrPbyO5PK7yJ5vaiWre7aQ9bmCtXAomvF1q3/qRwZp77k6i9R3 tWfXjZDOQokw0u6d6DYJ0Vkfcwheg2i/Mf/epQl7Pf846G3PgSnyVK6cRwerBl5a68w7xqVU 4KgAh0DePjtDcbcXsKRT9D63cfyfrNE+ea4i0SVik6+N4nAj1HbzWHTk2KIxTsJXypibOKFX 2VykltxutR1sUfZBYMkfU4PogE7NjVEU7KtuCOSAkYzIWrZNEQrxYkxHLJsWruhSYNRsqVBy KvY6JAsq/i5yhVd5JKKU8wIOgSwC9P6mXYRgwPyfg15GZpnw+Fpey4bCDkT5fMOaCcS+vSU1 UaFmC4Ogzpe2BW2DOaPU5Ik99zUFNn6cRmOOXArrryjFlLT5oSOe4IposgWzdwARAQABiQIl BBgBCAAPBQJZeKUKAhsMBQkJZgGAAAoJEKOGQNwGMqM5ELoP/jj9d9gF1Al4+9bngUlYohYu 0sxyZo9IZ7Yb7cHuJzOMqfgoP4tydP4QCuyd9Q2OHHL5AL4VFNb8SvqAxxYSPuDJTI3JZwI7 d8JTPKwpulMSUaJE8ZH9n8A/+sdC3CAD4QafVBcCcbFe1jifHmQRdDrvHV9Es14QVAOTZhnJ vweENyHEIxkpLsyUUDuVypIo6y/Cws+EBCWt27BJi9GH/EOTB0wb+2ghCs/i3h8a+bi+bS7L FCCm/AxIqxRurh2UySn0P/2+2eZvneJ1/uTgfxnjeSlwQJ1BWzMAdAHQO1/lnbyZgEZEtUZJ x9d9ASekTtJjBMKJXAw7GbB2dAA/QmbA+Q+Xuamzm/1imigz6L6sOt2n/X/SSc33w8RJUyor SvAIoG/zU2Y76pKTgbpQqMDmkmNYFMLcAukpvC4ki3Sf086TdMgkjqtnpTkEElMSFJC8npXv 3QnGGOIfFug/qs8z03DLPBz9VYS26jiiN7QIJVpeeEdN/LKnaz5LO+h5kNAyj44qdF2T2AiF HxnZnxO5JNP5uISQH3FjxxGxJkdJ8jKzZV7aT37sC+Rp0o3KNc+GXTR+GSVq87Xfuhx0LRST NK9ZhT0+qkiN7npFLtNtbzwqaqceq3XhafmCiw8xrtzCnlB/C4SiBr/93Ip4kihXJ0EuHSLn VujM7c/b4pps Organization: Red Hat Inc, Message-ID: <7fcb61d6-64f0-f3ae-5e32-0e9f587fdd49@redhat.com> Date: Mon, 11 Feb 2019 08:30:03 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <20190209195325-mutt-send-email-mst@kernel.org> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="bgcetFPJzTNKp4nh9DgTAgO3id5Syb3GZ" X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Mon, 11 Feb 2019 13:30:29 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --bgcetFPJzTNKp4nh9DgTAgO3id5Syb3GZ Content-Type: multipart/mixed; boundary="rxrbFi0rimh0fffvwaHt9J6zKSdjFAYyj"; protected-headers="v1" From: Nitesh Narayan Lal To: "Michael S. Tsirkin" , Alexander Duyck Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, rkrcmar@redhat.com, alexander.h.duyck@linux.intel.com, x86@kernel.org, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, pbonzini@redhat.com, tglx@linutronix.de, akpm@linux-foundation.org Message-ID: <7fcb61d6-64f0-f3ae-5e32-0e9f587fdd49@redhat.com> Subject: Re: [RFC PATCH 4/4] mm: Add merge page notifier References: <20190204181118.12095.38300.stgit@localhost.localdomain> <20190204181558.12095.83484.stgit@localhost.localdomain> <20190209195325-mutt-send-email-mst@kernel.org> In-Reply-To: <20190209195325-mutt-send-email-mst@kernel.org> --rxrbFi0rimh0fffvwaHt9J6zKSdjFAYyj Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Content-Language: en-US On 2/9/19 7:57 PM, Michael S. Tsirkin wrote: > On Mon, Feb 04, 2019 at 10:15:58AM -0800, Alexander Duyck wrote: >> From: Alexander Duyck >> >> Because the implementation was limiting itself to only providing hints= on >> pages huge TLB order sized or larger we introduced the possibility for= free >> pages to slip past us because they are freed as something less then >> huge TLB in size and aggregated with buddies later. >> >> To address that I am adding a new call arch_merge_page which is called= >> after __free_one_page has merged a pair of pages to create a higher or= der >> page. By doing this I am able to fill the gap and provide full coverag= e for >> all of the pages huge TLB order or larger. >> >> Signed-off-by: Alexander Duyck > Looks like this will be helpful whenever active free page > hints are added. So I think it's a good idea to > add a hook. > > However, could you split adding the hook to a separate > patch from the KVM hypercall based implementation? > > Then e.g. Nilal's patches could reuse it too. With the current design of my patch-set, if I use this hook to report free pages. I will end up making redundant hints for the same pfns. This is because the pages once freed by the host, are returned back to the buddy. > > >> --- >> arch/x86/include/asm/page.h | 12 ++++++++++++ >> arch/x86/kernel/kvm.c | 28 ++++++++++++++++++++++++++++ >> include/linux/gfp.h | 4 ++++ >> mm/page_alloc.c | 2 ++ >> 4 files changed, 46 insertions(+) >> >> diff --git a/arch/x86/include/asm/page.h b/arch/x86/include/asm/page.h= >> index 4487ad7a3385..9540a97c9997 100644 >> --- a/arch/x86/include/asm/page.h >> +++ b/arch/x86/include/asm/page.h >> @@ -29,6 +29,18 @@ static inline void arch_free_page(struct page *page= , unsigned int order) >> if (static_branch_unlikely(&pv_free_page_hint_enabled)) >> __arch_free_page(page, order); >> } >> + >> +struct zone; >> + >> +#define HAVE_ARCH_MERGE_PAGE >> +void __arch_merge_page(struct zone *zone, struct page *page, >> + unsigned int order); >> +static inline void arch_merge_page(struct zone *zone, struct page *pa= ge, >> + unsigned int order) >> +{ >> + if (static_branch_unlikely(&pv_free_page_hint_enabled)) >> + __arch_merge_page(zone, page, order); >> +} >> #endif >> =20 >> #include >> diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c >> index 09c91641c36c..957bb4f427bb 100644 >> --- a/arch/x86/kernel/kvm.c >> +++ b/arch/x86/kernel/kvm.c >> @@ -785,6 +785,34 @@ void __arch_free_page(struct page *page, unsigned= int order) >> PAGE_SIZE << order); >> } >> =20 >> +void __arch_merge_page(struct zone *zone, struct page *page, >> + unsigned int order) >> +{ >> + /* >> + * The merging logic has merged a set of buddies up to the >> + * KVM_PV_UNUSED_PAGE_HINT_MIN_ORDER. Since that is the case, take >> + * advantage of this moment to notify the hypervisor of the free >> + * memory. >> + */ >> + if (order !=3D KVM_PV_UNUSED_PAGE_HINT_MIN_ORDER) >> + return; >> + >> + /* >> + * Drop zone lock while processing the hypercall. This >> + * should be safe as the page has not yet been added >> + * to the buddy list as of yet and all the pages that >> + * were merged have had their buddy/guard flags cleared >> + * and their order reset to 0. >> + */ >> + spin_unlock(&zone->lock); >> + >> + kvm_hypercall2(KVM_HC_UNUSED_PAGE_HINT, page_to_phys(page), >> + PAGE_SIZE << order); >> + >> + /* reacquire lock and resume freeing memory */ >> + spin_lock(&zone->lock); >> +} >> + >> #ifdef CONFIG_PARAVIRT_SPINLOCKS >> =20 >> /* Kick a cpu by its apicid. Used to wake up a halted vcpu */ >> diff --git a/include/linux/gfp.h b/include/linux/gfp.h >> index fdab7de7490d..4746d5560193 100644 >> --- a/include/linux/gfp.h >> +++ b/include/linux/gfp.h >> @@ -459,6 +459,10 @@ static inline struct zonelist *node_zonelist(int = nid, gfp_t flags) >> #ifndef HAVE_ARCH_FREE_PAGE >> static inline void arch_free_page(struct page *page, int order) { } >> #endif >> +#ifndef HAVE_ARCH_MERGE_PAGE >> +static inline void >> +arch_merge_page(struct zone *zone, struct page *page, int order) { } >> +#endif >> #ifndef HAVE_ARCH_ALLOC_PAGE >> static inline void arch_alloc_page(struct page *page, int order) { } >> #endif >> diff --git a/mm/page_alloc.c b/mm/page_alloc.c >> index c954f8c1fbc4..7a1309b0b7c5 100644 >> --- a/mm/page_alloc.c >> +++ b/mm/page_alloc.c >> @@ -913,6 +913,8 @@ static inline void __free_one_page(struct page *pa= ge, >> page =3D page + (combined_pfn - pfn); >> pfn =3D combined_pfn; >> order++; >> + >> + arch_merge_page(zone, page, order); >> } >> if (max_order < MAX_ORDER) { >> /* If we are here, it means order is >=3D pageblock_order. --=20 Regards Nitesh --rxrbFi0rimh0fffvwaHt9J6zKSdjFAYyj-- --bgcetFPJzTNKp4nh9DgTAgO3id5Syb3GZ Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEkXcoRVGaqvbHPuAGo4ZA3AYyozkFAlxheNwACgkQo4ZA3AYy oznBhQ/8DTHV/Y4PGtL9dxvGU/FlAdRnEuPMHPw6hDGr5qcWCC9bkX9dfGAtoATp veCftnpMxcub00ObTcYFDsLg6OoJ5ThlgvZfQ/tKkzJO2X2AoMlW1GGF+jWRPSW6 5Zmw4/IRJEW433Hg73MfAili6l3YpgvHv1EJ95hsA318j/14YmQKMB3OPKR7e8kk 2R+0oD5QrS3hrjcsRWDOEBquMAt2JigPLv8TzqA+IdqdwNjFQ6vumXloMDUBVCym RADoNTWfAm1uHgLdlLNf2Fcoj8b2J/CVxWx7NgM3n+uPbU6PtcrLdXDFuR5wVjhN +GazNsOM/Y3joNNlB+dBmNwBFTDJEZgJDhJVxLpxVCHcMi8oB+iuWVf6MZ87ivr+ 8Rd/GReIo2wVDVb27T4Le/tcX9VIk3AOVTgZ3VwodHLT7a4/JJGKsmCko8nrr8EX XiYZzwsLaiGdQQx63ALUmDhOXN97uu8JLyIzs8+OHYklPs4mYMXYwaQruGRcRvUt 2HoY2UvARFy/7lfqQb8++gbwPPCsVbni0n1ERxinOtJV6kLkpB5u9pHEvTnIlqlp Xkn5pCqPqNV+X3F36GDsVnQ+vBXj3Uyd0/Wywr1JaW1ZWBVl3oP/KGoxc5JfU6/z faUhCYxovWqoTXQVtm60a0lu7w+Jis1ed4ZhhE+Br4bJYWbHALs= =X2Bz -----END PGP SIGNATURE----- --bgcetFPJzTNKp4nh9DgTAgO3id5Syb3GZ--