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=-9.8 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 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 A3BDAC433F1 for ; Wed, 22 Jul 2020 09:46:26 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 5531520714 for ; Wed, 22 Jul 2020 09:46:26 +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="irwtudD9" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5531520714 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 B2E316B0010; Wed, 22 Jul 2020 05:46:25 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id AE23D6B0022; Wed, 22 Jul 2020 05:46:25 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9CED56B0023; Wed, 22 Jul 2020 05:46:25 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0033.hostedemail.com [216.40.44.33]) by kanga.kvack.org (Postfix) with ESMTP id 8AB576B0010 for ; Wed, 22 Jul 2020 05:46:25 -0400 (EDT) Received: from smtpin16.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 4383110481486 for ; Wed, 22 Jul 2020 09:46:25 +0000 (UTC) X-FDA: 77065231530.16.boat10_2c0f15826f35 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin16.hostedemail.com (Postfix) with ESMTP id 0BFC51048146C for ; Wed, 22 Jul 2020 09:46:25 +0000 (UTC) X-HE-Tag: boat10_2c0f15826f35 X-Filterd-Recvd-Size: 7864 Received: from us-smtp-delivery-1.mimecast.com (us-smtp-1.mimecast.com [207.211.31.81]) by imf25.hostedemail.com (Postfix) with ESMTP for ; Wed, 22 Jul 2020 09:46:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1595411183; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=2xkRfN498qm5cSXp4IxetsBwjv9eFc020EXHuR3Y7wI=; b=irwtudD95LzYhnSHS3UCB5bU0fxgwYLaRIUaymPgDIv08pBsXpY2l3yUapJqZdhK50sQb9 DKwSEHmTr8Z84TFhmXcISp7jMgy5bly5qPYD3LeTLckfJuGxiO7692Oyadpf0G4YgNWysz vazSkB4ERsJ1zxF6AVJ5HiKDzX96iVQ= 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-261-kOzkAacGO8CjZtyVu-YDmg-1; Wed, 22 Jul 2020 05:46:19 -0400 X-MC-Unique: kOzkAacGO8CjZtyVu-YDmg-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 6210C80183C; Wed, 22 Jul 2020 09:46:18 +0000 (UTC) Received: from t480s.redhat.com (ovpn-113-254.ams2.redhat.com [10.36.113.254]) by smtp.corp.redhat.com (Postfix) with ESMTP id B42DC5D9CA; Wed, 22 Jul 2020 09:46:16 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-s390@vger.kernel.org, linux-mm@kvack.org, David Hildenbrand , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , Gerald Schaefer Subject: [PATCH v2 6/9] s390/vmem: cleanup empty page tables Date: Wed, 22 Jul 2020 11:45:55 +0200 Message-Id: <20200722094558.9828-7-david@redhat.com> In-Reply-To: <20200722094558.9828-1-david@redhat.com> References: <20200722094558.9828-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Rspamd-Queue-Id: 0BFC51048146C X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam02 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: Let's cleanup empty page tables. Consider only page tables that fully fall into the idendity mapping and the vmemmap range. As there are no valid accesses to vmem/vmemmap within non-populated range= s, the single tlb flush at the end should be sufficient. Cc: Heiko Carstens Cc: Vasily Gorbik Cc: Christian Borntraeger Cc: Gerald Schaefer Signed-off-by: David Hildenbrand --- arch/s390/mm/vmem.c | 102 +++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 101 insertions(+), 1 deletion(-) diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c index a2b79681df69d..b831f9f9130aa 100644 --- a/arch/s390/mm/vmem.c +++ b/arch/s390/mm/vmem.c @@ -63,6 +63,15 @@ pte_t __ref *vmem_pte_alloc(void) return pte; } =20 +static void vmem_pte_free(unsigned long *table) +{ + /* We don't expect boot memory to be removed ever. */ + if (!slab_is_available() || + WARN_ON_ONCE(PageReserved(virt_to_page(table)))) + return; + page_table_free(&init_mm, table); +} + /* __ref: we'll only call vmemmap_alloc_block() via vmemmap_populate() *= / static int __ref modify_pte_table(pmd_t *pmd, unsigned long addr, unsigned long end, bool add, bool direct) @@ -105,6 +114,21 @@ static int __ref modify_pte_table(pmd_t *pmd, unsign= ed long addr, return ret; } =20 +static void try_free_pte_table(pmd_t *pmd, unsigned long start) +{ + pte_t *pte; + int i; + + /* We can safely assume this is fully in 1:1 mapping & vmemmap area */ + pte =3D pte_offset_kernel(pmd, start); + for (i =3D 0; i < PTRS_PER_PTE; i++, pte++) + if (!pte_none(*pte)) + return; + + vmem_pte_free(__va(pmd_deref(*pmd))); + pmd_clear(pmd); +} + /* __ref: we'll only call vmemmap_alloc_block() via vmemmap_populate() *= / static int __ref modify_pmd_table(pud_t *pud, unsigned long addr, unsigned long end, bool add, bool direct) @@ -171,6 +195,8 @@ static int __ref modify_pmd_table(pud_t *pud, unsigne= d long addr, ret =3D modify_pte_table(pmd, addr, next, add, direct); if (ret) goto out; + if (!add) + try_free_pte_table(pmd, addr & PMD_MASK); } ret =3D 0; out: @@ -179,6 +205,29 @@ static int __ref modify_pmd_table(pud_t *pud, unsign= ed long addr, return ret; } =20 +static void try_free_pmd_table(pud_t *pud, unsigned long start) +{ + const unsigned long end =3D start + PUD_SIZE; + pmd_t *pmd; + int i; + + /* Don't mess with any tables not fully in 1:1 mapping & vmemmap area *= / + if (end > VMALLOC_START) + return; +#ifdef CONFIG_KASAN + if (start < KASAN_SHADOW_END && KASAN_SHADOW_START > end) + return; +#endif + + pmd =3D pmd_offset(pud, start); + for (i =3D 0; i < PTRS_PER_PMD; i++, pmd++) + if (!pmd_none(*pmd)) + return; + + vmem_free_pages(pud_deref(*pud), CRST_ALLOC_ORDER); + pud_clear(pud); +} + static int modify_pud_table(p4d_t *p4d, unsigned long addr, unsigned lon= g end, bool add, bool direct) { @@ -225,6 +274,8 @@ static int modify_pud_table(p4d_t *p4d, unsigned long= addr, unsigned long end, ret =3D modify_pmd_table(pud, addr, next, add, direct); if (ret) goto out; + if (!add) + try_free_pmd_table(pud, addr & PUD_MASK); } ret =3D 0; out: @@ -233,6 +284,29 @@ static int modify_pud_table(p4d_t *p4d, unsigned lon= g addr, unsigned long end, return ret; } =20 +static void try_free_pud_table(p4d_t *p4d, unsigned long start) +{ + const unsigned long end =3D start + P4D_SIZE; + pud_t *pud; + int i; + + /* Don't mess with any tables not fully in 1:1 mapping & vmemmap area *= / + if (end > VMALLOC_START) + return; +#ifdef CONFIG_KASAN + if (start < KASAN_SHADOW_END && KASAN_SHADOW_START > end) + return; +#endif + + pud =3D pud_offset(p4d, start); + for (i =3D 0; i < PTRS_PER_PUD; i++, pud++) + if (!pud_none(*pud)) + return; + + vmem_free_pages(p4d_deref(*p4d), CRST_ALLOC_ORDER); + p4d_clear(p4d); +} + static int modify_p4d_table(pgd_t *pgd, unsigned long addr, unsigned lon= g end, bool add, bool direct) { @@ -257,12 +331,37 @@ static int modify_p4d_table(pgd_t *pgd, unsigned lo= ng addr, unsigned long end, ret =3D modify_pud_table(p4d, addr, next, add, direct); if (ret) goto out; + if (!add) + try_free_pud_table(p4d, addr & P4D_MASK); } ret =3D 0; out: return ret; } =20 +static void try_free_p4d_table(pgd_t *pgd, unsigned long start) +{ + const unsigned long end =3D start + PGDIR_SIZE; + p4d_t *p4d; + int i; + + /* Don't mess with any tables not fully in 1:1 mapping & vmemmap area *= / + if (end > VMALLOC_START) + return; +#ifdef CONFIG_KASAN + if (start < KASAN_SHADOW_END && KASAN_SHADOW_START > end) + return; +#endif + + p4d =3D p4d_offset(pgd, start); + for (i =3D 0; i < PTRS_PER_P4D; i++, p4d++) + if (!p4d_none(*p4d)) + return; + + vmem_free_pages(pgd_deref(*pgd), CRST_ALLOC_ORDER); + pgd_clear(pgd); +} + static int modify_pagetable(unsigned long start, unsigned long end, bool= add, bool direct) { @@ -291,6 +390,8 @@ static int modify_pagetable(unsigned long start, unsi= gned long end, bool add, ret =3D modify_p4d_table(pgd, addr, next, add, direct); if (ret) goto out; + if (!add) + try_free_p4d_table(pgd, addr & PGDIR_MASK); } ret =3D 0; out: @@ -319,7 +420,6 @@ static int vmem_add_range(unsigned long start, unsign= ed long size) =20 /* * Remove a physical memory range from the 1:1 mapping. - * Currently only invalidates page table entries. */ static void vmem_remove_range(unsigned long start, unsigned long size) { --=20 2.26.2