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=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT 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 5CD45C3A5A2 for ; Tue, 3 Sep 2019 12:45:13 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id DA23820674 for ; Tue, 3 Sep 2019 12:45:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DA23820674 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 46N69f3n8czDqTw for ; Tue, 3 Sep 2019 22:45:10 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=linux.ibm.com (client-ip=148.163.156.1; helo=mx0a-001b2d01.pphosted.com; envelope-from=aneesh.kumar@linux.ibm.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.ibm.com Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 46N65470qPzDqVJ for ; Tue, 3 Sep 2019 22:41:12 +1000 (AEST) Received: from pps.filterd (m0098409.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x83Cbb60060176; Tue, 3 Sep 2019 08:41:08 -0400 Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com with ESMTP id 2usqvyh4r2-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 03 Sep 2019 08:41:08 -0400 Received: from m0098409.ppops.net (m0098409.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.27/8.16.0.27) with SMTP id x83CcKDS063624; Tue, 3 Sep 2019 08:41:07 -0400 Received: from ppma01wdc.us.ibm.com (fd.55.37a9.ip4.static.sl-reverse.com [169.55.85.253]) by mx0a-001b2d01.pphosted.com with ESMTP id 2usqvyh4pt-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 03 Sep 2019 08:41:07 -0400 Received: from pps.filterd (ppma01wdc.us.ibm.com [127.0.0.1]) by ppma01wdc.us.ibm.com (8.16.0.27/8.16.0.27) with SMTP id x83CenTV004093; Tue, 3 Sep 2019 12:41:06 GMT Received: from b03cxnp08028.gho.boulder.ibm.com (b03cxnp08028.gho.boulder.ibm.com [9.17.130.20]) by ppma01wdc.us.ibm.com with ESMTP id 2uqgh6jf82-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 03 Sep 2019 12:41:06 +0000 Received: from b03ledav006.gho.boulder.ibm.com (b03ledav006.gho.boulder.ibm.com [9.17.130.237]) by b03cxnp08028.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x83Cf5bp58065252 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 3 Sep 2019 12:41:05 GMT Received: from b03ledav006.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 52382C6055; Tue, 3 Sep 2019 12:41:05 +0000 (GMT) Received: from b03ledav006.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 43D75C6059; Tue, 3 Sep 2019 12:41:03 +0000 (GMT) Received: from skywalker.ibmuc.com (unknown [9.199.33.18]) by b03ledav006.gho.boulder.ibm.com (Postfix) with ESMTP; Tue, 3 Sep 2019 12:41:02 +0000 (GMT) From: "Aneesh Kumar K.V" To: npiggin@gmail.com, paulus@samba.org, mpe@ellerman.id.au Subject: [RFC PATCH 1/3] mm/powerpc/book3s64/radix: Remove unused code. Date: Tue, 3 Sep 2019 18:10:52 +0530 Message-Id: <20190903124054.30611-1-aneesh.kumar@linux.ibm.com> X-Mailer: git-send-email 2.21.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-09-03_01:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=2 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1909030132 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "Aneesh Kumar K.V" , linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" mm_tlb_flush_nested change was added in the mmu gather tlb flush to handle the case of parallel pte invalidate happening with mmap_sem held in read mode. This fix was done by commit: 02390f66bd23 ("powerpc/64s/radix: Fix MADV_[FREE|DONTNEED] TLB flush miss problem with THP") and the problem is explained in detail in commit: 99baac21e458 ("mm: fix MADV_[FREE|DONTNEED] TLB flush miss problem") This was later updated by commit: 7a30df49f63a ("mm: mmu_gather: remove __tlb_reset_range() for force flush") to do a full mm flush rather than a range flush. By commit: dd2283f2605e ("mm: mmap: zap pages with read mmap_sem in munmap") we are also now allowing a page table free in mmap_sem read mode which means we should do a PWC flush too. Our current full mm flush imply a PWC flush. With all the above change the mm_tlb_flush_nested(mm) branch in radix__tlb_flush will never be taken because for the nested case we would have taken the if (tlb->fullmm) branch. This patch removes the unused code. Also, remove the gflush change in __radix__flush_tlb_range that was added to handle the range tlb flush code. We only check for THP there because hugetlb is flushed via a different code path where page size is explicitly specified This is a partial revert of commit: 02390f66bd23 ("powerpc/64s/radix: Fix MADV_[FREE|DONTNEED] TLB flush miss problem with THP") Signed-off-by: Aneesh Kumar K.V --- arch/powerpc/mm/book3s64/radix_tlb.c | 62 +++------------------------- 1 file changed, 6 insertions(+), 56 deletions(-) diff --git a/arch/powerpc/mm/book3s64/radix_tlb.c b/arch/powerpc/mm/book3s64/radix_tlb.c index 71f7fede2fa4..059fef601eb9 100644 --- a/arch/powerpc/mm/book3s64/radix_tlb.c +++ b/arch/powerpc/mm/book3s64/radix_tlb.c @@ -692,8 +692,7 @@ static unsigned long tlb_single_page_flush_ceiling __read_mostly = 33; static unsigned long tlb_local_single_page_flush_ceiling __read_mostly = POWER9_TLB_SETS_RADIX * 2; static inline void __radix__flush_tlb_range(struct mm_struct *mm, - unsigned long start, unsigned long end, - bool flush_all_sizes) + unsigned long start, unsigned long end) { unsigned long pid; @@ -735,26 +734,16 @@ static inline void __radix__flush_tlb_range(struct mm_struct *mm, _tlbie_pid(pid, RIC_FLUSH_TLB); } } else { - bool hflush = flush_all_sizes; - bool gflush = flush_all_sizes; + bool hflush = false; unsigned long hstart, hend; - unsigned long gstart, gend; - if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) - hflush = true; - - if (hflush) { + if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) { hstart = (start + PMD_SIZE - 1) & PMD_MASK; hend = end & PMD_MASK; if (hstart == hend) hflush = false; - } - - if (gflush) { - gstart = (start + PUD_SIZE - 1) & PUD_MASK; - gend = end & PUD_MASK; - if (gstart == gend) - gflush = false; + else + hflush = true; } asm volatile("ptesync": : :"memory"); @@ -763,18 +752,12 @@ static inline void __radix__flush_tlb_range(struct mm_struct *mm, if (hflush) __tlbiel_va_range(hstart, hend, pid, PMD_SIZE, MMU_PAGE_2M); - if (gflush) - __tlbiel_va_range(gstart, gend, pid, - PUD_SIZE, MMU_PAGE_1G); asm volatile("ptesync": : :"memory"); } else { __tlbie_va_range(start, end, pid, page_size, mmu_virtual_psize); if (hflush) __tlbie_va_range(hstart, hend, pid, PMD_SIZE, MMU_PAGE_2M); - if (gflush) - __tlbie_va_range(gstart, gend, pid, - PUD_SIZE, MMU_PAGE_1G); fixup_tlbie(); asm volatile("eieio; tlbsync; ptesync": : :"memory"); } @@ -791,7 +774,7 @@ void radix__flush_tlb_range(struct vm_area_struct *vma, unsigned long start, return radix__flush_hugetlb_tlb_range(vma, start, end); #endif - __radix__flush_tlb_range(vma->vm_mm, start, end, false); + __radix__flush_tlb_range(vma->vm_mm, start, end); } EXPORT_SYMBOL(radix__flush_tlb_range); @@ -882,39 +865,6 @@ void radix__tlb_flush(struct mmu_gather *tlb) */ if (tlb->fullmm) { __flush_all_mm(mm, true); -#if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLB_PAGE) - } else if (mm_tlb_flush_nested(mm)) { - /* - * If there is a concurrent invalidation that is clearing ptes, - * then it's possible this invalidation will miss one of those - * cleared ptes and miss flushing the TLB. If this invalidate - * returns before the other one flushes TLBs, that can result - * in it returning while there are still valid TLBs inside the - * range to be invalidated. - * - * See mm/memory.c:tlb_finish_mmu() for more details. - * - * The solution to this is ensure the entire range is always - * flushed here. The problem for powerpc is that the flushes - * are page size specific, so this "forced flush" would not - * do the right thing if there are a mix of page sizes in - * the range to be invalidated. So use __flush_tlb_range - * which invalidates all possible page sizes in the range. - * - * PWC flush probably is not be required because the core code - * shouldn't free page tables in this path, but accounting - * for the possibility makes us a bit more robust. - * - * need_flush_all is an uncommon case because page table - * teardown should be done with exclusive locks held (but - * after locks are dropped another invalidate could come - * in), it could be optimized further if necessary. - */ - if (!tlb->need_flush_all) - __radix__flush_tlb_range(mm, start, end, true); - else - radix__flush_all_mm(mm); -#endif } else if ( (psize = radix_get_mmu_psize(page_size)) == -1) { if (!tlb->need_flush_all) radix__flush_tlb_mm(mm); -- 2.21.0