From patchwork Fri Apr 30 14:36:06 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?q?Leonardo_Br=C3=A1s?= X-Patchwork-Id: 1472351 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=2404:9400:2:0:216:3eff:fee1:b9f1; helo=lists.ozlabs.org; envelope-from=linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org; receiver=) Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20161025 header.b=c8VZuzhH; dkim-atps=neutral Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2404:9400:2:0:216:3eff:fee1:b9f1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4FWw1m6cXXz9sW4 for ; Sat, 1 May 2021 00:37:16 +1000 (AEST) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4FWw1m66mCz3bc8 for ; Sat, 1 May 2021 00:37:16 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20161025 header.b=c8VZuzhH; dkim-atps=neutral X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=gmail.com (client-ip=2607:f8b0:4864:20::735; helo=mail-qk1-x735.google.com; envelope-from=leobras.c@gmail.com; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20161025 header.b=c8VZuzhH; dkim-atps=neutral Received: from mail-qk1-x735.google.com (mail-qk1-x735.google.com [IPv6:2607:f8b0:4864:20::735]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4FWw1C0VbSz3018 for ; Sat, 1 May 2021 00:36:46 +1000 (AEST) Received: by mail-qk1-x735.google.com with SMTP id d19so35128510qkk.12 for ; Fri, 30 Apr 2021 07:36:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=alyS840WpTY55RdF+7Kqh/069+/rmbTaDiI+qnnTJwM=; b=c8VZuzhHSyKUnoyRpry9HnofH2E3TKJSC5Dx7anszw68lOhGBhyzyGz7fRsk0Wtayy WQiWwi6GDC3A8SPS32rdvg9m3/o5XrwEKWzX/CDDrimzSD7zypjo2/Z7FkelKzlfbAQs 8M3hLf8iioo8MjzGBapd1TCJ0NOVNgOP3S0zyRZ5g/VCTnA4vncy/SvAB2IyoQqXwtXt I5THmLp/IHCjGsPhQ5CAouOFAh/v9u9lH9RyRTlupM+oJUsiOv8qAj7kqndH5y6fJuXf RCSbYfGJao1cVYHjKZ6QwWqu3SwbQDa6TfsmgDWLQ05xMRL79jsCiQ4a94wdGgfV3lbn C3CA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=alyS840WpTY55RdF+7Kqh/069+/rmbTaDiI+qnnTJwM=; b=HIAF+LogUH7tTX4Kho/Ke4lRtbDCku2JX78ojA6uyYiIV7UH99dB8+YR0y43n6KTvA ZzEmaPRGZTiCPjV9Az5ZmfpAjd7n213tn4ZaYDnQqNWvOMC3OYui1Wn5sE683yziocty /vbKWE60nEys3h/2asSWU20mMq36dFuWsuwpmzCQWJxpKMAmjPXSQr+Rf98tLsT1yhmt T+nbAehovl5WC77crc//mM8vlhCRF+MYQENJ5mN4Tz8/+Ewa8xmBWYzlrXPGaIV7EAwI CfTHhV0HAKqfmmJqQJIXLaNe6BpN3DgFKABvZRC17l712Nu0SUx0oqgfbhbdNZP55A2y ZQQw== X-Gm-Message-State: AOAM530WbHKHtP/+f2AeYnxOHswPaBVqDrd2Jukxg4EszjX0psFUau2D u2KTcQGMjm5yToDCOx0278c= X-Google-Smtp-Source: ABdhPJw7izh38YAvpwf5z4TKLLJtQ6zNbOrQKLzjbpHnS+3xmj9H9Dq846g3uQjOCGoDxuVcsk5ulg== X-Received: by 2002:a37:688:: with SMTP id 130mr5759408qkg.499.1619793404447; Fri, 30 Apr 2021 07:36:44 -0700 (PDT) Received: from li-908e0a4c-2250-11b2-a85c-f027e903211b.ibm.com.com ([2804:14c:482:7b04::1001]) by smtp.gmail.com with ESMTPSA id 190sm1532560qki.115.2021.04.30.07.36.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 30 Apr 2021 07:36:44 -0700 (PDT) From: Leonardo Bras To: Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Leonardo Bras , Sandipan Das , Mike Rapoport , Andrew Morton , "Aneesh Kumar K.V" , Nicholas Piggin , Nathan Lynch , David Hildenbrand , Scott Cheloha , Laurent Dufour Subject: [PATCH v2 1/3] powerpc/mm/hash: Avoid resizing-down HPT on first memory hotplug Date: Fri, 30 Apr 2021 11:36:06 -0300 Message-Id: <20210430143607.135005-2-leobras.c@gmail.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210430143607.135005-1-leobras.c@gmail.com> References: <20210430143607.135005-1-leobras.c@gmail.com> MIME-Version: 1.0 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: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" Because hypervisors may need to create HPTs without knowing the guest page size, the smallest used page-size (4k) may be chosen, resulting in a HPT that is possibly bigger than needed. On a guest with bigger page-sizes, the amount of entries for HTP may be too high, causing the guest to ask for a HPT resize-down on the first hotplug. This becomes a problem when HPT resize-down fails, and causes the HPT resize to be performed on every LMB added, until HPT size is compatible to guest memory size, causing a major slowdown. So, avoiding HPT resizing-down on hot-add significantly improves memory hotplug times. As an example, hotplugging 256GB on a 129GB guest took 710s without this patch, and 21s after applied. Signed-off-by: Leonardo Bras Reviewed-by: David Gibson --- arch/powerpc/mm/book3s64/hash_utils.c | 36 ++++++++++++++++----------- 1 file changed, 21 insertions(+), 15 deletions(-) diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c index 581b20a2feaf..608e4ed397a9 100644 --- a/arch/powerpc/mm/book3s64/hash_utils.c +++ b/arch/powerpc/mm/book3s64/hash_utils.c @@ -795,7 +795,7 @@ static unsigned long __init htab_get_table_size(void) } #ifdef CONFIG_MEMORY_HOTPLUG -static int resize_hpt_for_hotplug(unsigned long new_mem_size) +static int resize_hpt_for_hotplug(unsigned long new_mem_size, bool shrinking) { unsigned target_hpt_shift; @@ -804,19 +804,25 @@ static int resize_hpt_for_hotplug(unsigned long new_mem_size) target_hpt_shift = htab_shift_for_mem_size(new_mem_size); - /* - * To avoid lots of HPT resizes if memory size is fluctuating - * across a boundary, we deliberately have some hysterisis - * here: we immediately increase the HPT size if the target - * shift exceeds the current shift, but we won't attempt to - * reduce unless the target shift is at least 2 below the - * current shift - */ - if (target_hpt_shift > ppc64_pft_size || - target_hpt_shift < ppc64_pft_size - 1) - return mmu_hash_ops.resize_hpt(target_hpt_shift); + if (shrinking) { - return 0; + /* + * To avoid lots of HPT resizes if memory size is fluctuating + * across a boundary, we deliberately have some hysterisis + * here: we immediately increase the HPT size if the target + * shift exceeds the current shift, but we won't attempt to + * reduce unless the target shift is at least 2 below the + * current shift + */ + + if (target_hpt_shift >= ppc64_pft_size - 1) + return 0; + + } else if (target_hpt_shift <= ppc64_pft_size) { + return 0; + } + + return mmu_hash_ops.resize_hpt(target_hpt_shift); } int hash__create_section_mapping(unsigned long start, unsigned long end, @@ -829,7 +835,7 @@ int hash__create_section_mapping(unsigned long start, unsigned long end, return -1; } - resize_hpt_for_hotplug(memblock_phys_mem_size()); + resize_hpt_for_hotplug(memblock_phys_mem_size(), false); rc = htab_bolt_mapping(start, end, __pa(start), pgprot_val(prot), mmu_linear_psize, @@ -848,7 +854,7 @@ int hash__remove_section_mapping(unsigned long start, unsigned long end) int rc = htab_remove_mapping(start, end, mmu_linear_psize, mmu_kernel_ssize); - if (resize_hpt_for_hotplug(memblock_phys_mem_size()) == -ENOSPC) + if (resize_hpt_for_hotplug(memblock_phys_mem_size(), true) == -ENOSPC) pr_warn("Hash collision while resizing HPT\n"); return rc; From patchwork Fri Apr 30 14:36:08 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?q?Leonardo_Br=C3=A1s?= X-Patchwork-Id: 1472352 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=112.213.38.117; helo=lists.ozlabs.org; envelope-from=linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org; receiver=) Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20161025 header.b=rO50kzg0; dkim-atps=neutral Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4FWw2F0ssjz9sW5 for ; Sat, 1 May 2021 00:37:41 +1000 (AEST) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4FWw2F0L8mz3btY for ; Sat, 1 May 2021 00:37:41 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20161025 header.b=rO50kzg0; dkim-atps=neutral X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=gmail.com (client-ip=2607:f8b0:4864:20::82e; helo=mail-qt1-x82e.google.com; envelope-from=leobras.c@gmail.com; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20161025 header.b=rO50kzg0; dkim-atps=neutral Received: from mail-qt1-x82e.google.com (mail-qt1-x82e.google.com [IPv6:2607:f8b0:4864:20::82e]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4FWw1W1Fdfz3037 for ; Sat, 1 May 2021 00:37:02 +1000 (AEST) Received: by mail-qt1-x82e.google.com with SMTP id o1so10148490qta.1 for ; Fri, 30 Apr 2021 07:37:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=nrdezJ4pdCtm9VV6EXYt28y/b60CBWuF37yCYjbQazM=; b=rO50kzg0l9E+8Eg+I65gJrSxNnjQtRijxEk2BsbLQoYrMAxxd+6IJf1LdDx3tU5zev 1nqp89tKL4Rh4bgn/90v/493AFaPuDvFQvFoAbjKgeE0zh4bGQE0p2h3ASQiTOJWKOpl FmebhSkeRXDQyEoXa30OO/Ij+zkoURFOYaNXF1683ve/nowQwTk0KD1CDHG2hezw4fQY zp5R6jBHMdgfiuC1k7pAZAL4hEqTAS5TVLcmmd0JiXVOJRgAw1DDkI4SenOD7kqRcNVi tnCPDB7CVNWHug6yLfQR2AMxXgDlqZhh1Bsfbk4bY44wIw1jcLAz8JEw330qSLsfOgqR HEtA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=nrdezJ4pdCtm9VV6EXYt28y/b60CBWuF37yCYjbQazM=; b=DVX7UoT3Ykt7499FTf26bUUj3c28LfSEf0CQKlKs4BMNz5uO9I1wvhSBbX4Wb4lxbk +XIu+C9qEEwxstrzhbKZpOFermBRvzM/8ydsLnHBDgpbbeGrU13Ex6KgMcr8UI+AX6UB HbQAoZHrKnSChP1SUs8CfVv654HgzCflxJV/crrjLnUmEdyEQHglZ+eOavBTIMYb1FfC f8van7YAs3F9wCJrU/62BmIur73Ne0muhMFii6H2zED1S7MOnDfi7yvpfWhk2M0ciEIn Qj1wVVPIhi4Ehya4sQEpfhk82nIjmhKuv4V5915QvnG1H+72JcvR8n+H4/SY00znIzFN I5Gg== X-Gm-Message-State: AOAM532FqeiFIt1PSOHK5l+WRqmdOUpBMuxZpT42sev7O9T8MnhqilZt 8NbZd/dqV6Amltws74Ji1nemEVlbdS0= X-Google-Smtp-Source: ABdhPJxhmKbcPVKKKaeOcfVyZbISGyjoYrD0vwX7Ak3/6ff5O4h3kDte6NVXtK31M5o/UXRQAe2Dew== X-Received: by 2002:ac8:75ca:: with SMTP id z10mr4722997qtq.137.1619793420373; Fri, 30 Apr 2021 07:37:00 -0700 (PDT) Received: from li-908e0a4c-2250-11b2-a85c-f027e903211b.ibm.com.com ([2804:14c:482:7b04::1001]) by smtp.gmail.com with ESMTPSA id 190sm1532560qki.115.2021.04.30.07.36.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 30 Apr 2021 07:37:00 -0700 (PDT) From: Leonardo Bras To: Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Leonardo Bras , Sandipan Das , Mike Rapoport , Andrew Morton , "Aneesh Kumar K.V" , Nicholas Piggin , Nathan Lynch , David Hildenbrand , Scott Cheloha , Laurent Dufour Subject: [PATCH v2 2/3] powerpc/mm/hash: Avoid multiple HPT resize-ups on memory hotplug Date: Fri, 30 Apr 2021 11:36:08 -0300 Message-Id: <20210430143607.135005-3-leobras.c@gmail.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210430143607.135005-1-leobras.c@gmail.com> References: <20210430143607.135005-1-leobras.c@gmail.com> MIME-Version: 1.0 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: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" Every time a memory hotplug happens, and the memory limit crosses a 2^n value, it may be necessary to perform HPT resizing-up, which can take some time (over 100ms in my tests). It usually is not an issue, but it can take some time if a lot of memory is added to a guest with little starting memory: Adding 256G to a 2GB guest, for example will require 8 HPT resizes. Perform an HPT resize before memory hotplug, updating HPT to its final size (considering a successful hotplug), taking the number of HPT resizes to at most one per memory hotplug action. Signed-off-by: Leonardo Bras Reviewed-by: David Gibson --- arch/powerpc/include/asm/book3s/64/hash.h | 2 ++ arch/powerpc/mm/book3s64/hash_utils.c | 20 +++++++++++++++++++ .../platforms/pseries/hotplug-memory.c | 9 +++++++++ 3 files changed, 31 insertions(+) diff --git a/arch/powerpc/include/asm/book3s/64/hash.h b/arch/powerpc/include/asm/book3s/64/hash.h index d959b0195ad9..fad4af8b8543 100644 --- a/arch/powerpc/include/asm/book3s/64/hash.h +++ b/arch/powerpc/include/asm/book3s/64/hash.h @@ -255,6 +255,8 @@ int hash__create_section_mapping(unsigned long start, unsigned long end, int nid, pgprot_t prot); int hash__remove_section_mapping(unsigned long start, unsigned long end); +void hash_batch_expand_prepare(unsigned long newsize); + #endif /* !__ASSEMBLY__ */ #endif /* __KERNEL__ */ #endif /* _ASM_POWERPC_BOOK3S_64_HASH_H */ diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c index 608e4ed397a9..3fa395b3fe57 100644 --- a/arch/powerpc/mm/book3s64/hash_utils.c +++ b/arch/powerpc/mm/book3s64/hash_utils.c @@ -859,6 +859,26 @@ int hash__remove_section_mapping(unsigned long start, unsigned long end) return rc; } + +void hash_batch_expand_prepare(unsigned long newsize) +{ + const u64 starting_size = ppc64_pft_size; + + /* + * Resizing-up HPT should never fail, but there are some cases system starts with higher + * SHIFT than required, and we go through the funny case of resizing HPT down while + * adding memory + */ + + while (resize_hpt_for_hotplug(newsize, false) == -ENOSPC) { + newsize *= 2; + pr_warn("Hash collision while resizing HPT\n"); + + /* Do not try to resize to the starting size, or bigger value */ + if (htab_shift_for_mem_size(newsize) >= starting_size) + break; + } +} #endif /* CONFIG_MEMORY_HOTPLUG */ static void __init hash_init_partition_table(phys_addr_t hash_table, diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c index 8377f1f7c78e..48b2cfe4ce69 100644 --- a/arch/powerpc/platforms/pseries/hotplug-memory.c +++ b/arch/powerpc/platforms/pseries/hotplug-memory.c @@ -13,6 +13,7 @@ #include #include #include +#include #include #include @@ -671,6 +672,10 @@ static int dlpar_memory_add_by_count(u32 lmbs_to_add) if (lmbs_available < lmbs_to_add) return -EINVAL; + if (!radix_enabled()) + hash_batch_expand_prepare(memblock_phys_mem_size() + + lmbs_to_add * drmem_lmb_size()); + for_each_drmem_lmb(lmb) { if (lmb->flags & DRCONF_MEM_ASSIGNED) continue; @@ -788,6 +793,10 @@ static int dlpar_memory_add_by_ic(u32 lmbs_to_add, u32 drc_index) if (lmbs_available < lmbs_to_add) return -EINVAL; + if (!radix_enabled()) + hash_batch_expand_prepare(memblock_phys_mem_size() + + lmbs_to_add * drmem_lmb_size()); + for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) { if (lmb->flags & DRCONF_MEM_ASSIGNED) continue; From patchwork Fri Apr 30 14:36:10 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?q?Leonardo_Br=C3=A1s?= X-Patchwork-Id: 1472353 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=112.213.38.117; helo=lists.ozlabs.org; envelope-from=linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org; receiver=) Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20161025 header.b=W2yHmrJl; dkim-atps=neutral Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4FWw2j6v4wz9sW4 for ; Sat, 1 May 2021 00:38:05 +1000 (AEST) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4FWw2j6N3wz303t for ; Sat, 1 May 2021 00:38:05 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20161025 header.b=W2yHmrJl; dkim-atps=neutral X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=gmail.com (client-ip=2607:f8b0:4864:20::72a; helo=mail-qk1-x72a.google.com; envelope-from=leobras.c@gmail.com; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20161025 header.b=W2yHmrJl; dkim-atps=neutral Received: from mail-qk1-x72a.google.com (mail-qk1-x72a.google.com [IPv6:2607:f8b0:4864:20::72a]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4FWw1s2gPqz3bpP for ; Sat, 1 May 2021 00:37:21 +1000 (AEST) Received: by mail-qk1-x72a.google.com with SMTP id o27so1977070qkj.9 for ; Fri, 30 Apr 2021 07:37:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=sbxM0d7iVP2AFAHnR5wZZv7UonG+3h5RRC/2YZAfwa4=; b=W2yHmrJlKhqzfDfSmZkFdYjO7Q/7VDJpMrkZ9dkSwloDYkRUUgzWLpaosA11jGrl8/ EKIu8x9KNrhqigpOeWNNSyDsC/pQ7qdBBSHRcA8VN4N+zqpovc7B8sOeW+sP2nbN3B8K xTkt2U+tO3aLHjEN20dTP1tzDwWkj/2u381y3T2/yZZkCjnJb+jtdaSduzGhMv7ZS/cs mfrHzRamccNEiHMFHAoLj15223nRtWDhd/zRxqnSOijXdCsdRrWYBpSrUdqCTgDMew8t gAprsO152s38k4sKUZXHHxP3pqlk9cz79wyipVvMMYkSZWEHzbUqdS5TJvaWr943Otam OTCA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=sbxM0d7iVP2AFAHnR5wZZv7UonG+3h5RRC/2YZAfwa4=; b=WqHydanN4X87x+eH6RN3OC9rdvb8zsxr1LMTwTa49PjiTPZUh0UDbPt0sbka2fo7vA cbxyfxte0N23/e9BOvaNgHhFpFw939/nSLIuyTO05Ln0NfdzfLCn927GiG/LjeRaPstU sprGH0waYw65zHVUfw2kCfhiCBL8t69q/lyJBa9a3cihx3b+d4ZLJzaulpkqqkGHp0x8 W9ltaW6TUwje+DOydsS1sCEndRRFBZKHo6l8YrSZt6sg5tYlIZYthQFYtouRLAq1jzBK 2McbhtKPCQSBWGq03grxrf+8994WCFlw9KL0gl20BJw4AP34vdINagE1muPdFe6XkWFN GxJw== X-Gm-Message-State: AOAM532w31ZhZRWftGUSS1nwO8MZ4waqcXW3cy2f1m75A6/xSAV1lAKu kzof9unLaAwGXU4hKMvxnM8= X-Google-Smtp-Source: ABdhPJyojzoDSFGiBlevl0kCCOc/+/Da+PIfH24WUxdcJM8zJY5iN9DVGHlJXjTAtjom3orRq1WWlA== X-Received: by 2002:a37:9802:: with SMTP id a2mr5961659qke.473.1619793438928; Fri, 30 Apr 2021 07:37:18 -0700 (PDT) Received: from li-908e0a4c-2250-11b2-a85c-f027e903211b.ibm.com.com ([2804:14c:482:7b04::1001]) by smtp.gmail.com with ESMTPSA id 190sm1532560qki.115.2021.04.30.07.37.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 30 Apr 2021 07:37:18 -0700 (PDT) From: Leonardo Bras To: Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Leonardo Bras , Sandipan Das , Mike Rapoport , Andrew Morton , "Aneesh Kumar K.V" , Nicholas Piggin , Nathan Lynch , David Hildenbrand , Scott Cheloha , Laurent Dufour Subject: [PATCH v2 3/3] powerpc/mm/hash: Avoid multiple HPT resize-downs on memory hotunplug Date: Fri, 30 Apr 2021 11:36:10 -0300 Message-Id: <20210430143607.135005-4-leobras.c@gmail.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210430143607.135005-1-leobras.c@gmail.com> References: <20210430143607.135005-1-leobras.c@gmail.com> MIME-Version: 1.0 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: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" During memory hotunplug, after each LMB is removed, the HPT may be resized-down if it would map a max of 4 times the current amount of memory. (2 shifts, due to introduced histeresis) It usually is not an issue, but it can take a lot of time if HPT resizing-down fails. This happens because resize-down failures usually repeat at each LMB removal, until there are no more bolted entries conflict, which can take a while to happen. This can be solved by doing a single HPT resize at the end of memory hotunplug, after all requested entries are removed. To make this happen, it's necessary to temporarily disable all HPT resize-downs before hotunplug, re-enable them after hotunplug ends, and then resize-down HPT to the current memory size. As an example, hotunplugging 256GB from a 385GB guest took 621s without this patch, and 100s after applied. Signed-off-by: Leonardo Bras --- arch/powerpc/include/asm/book3s/64/hash.h | 2 + arch/powerpc/mm/book3s64/hash_utils.c | 45 +++++++++++++++++-- .../platforms/pseries/hotplug-memory.c | 26 +++++++++++ 3 files changed, 70 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/include/asm/book3s/64/hash.h b/arch/powerpc/include/asm/book3s/64/hash.h index fad4af8b8543..6cd66e7e98c9 100644 --- a/arch/powerpc/include/asm/book3s/64/hash.h +++ b/arch/powerpc/include/asm/book3s/64/hash.h @@ -256,6 +256,8 @@ int hash__create_section_mapping(unsigned long start, unsigned long end, int hash__remove_section_mapping(unsigned long start, unsigned long end); void hash_batch_expand_prepare(unsigned long newsize); +void hash_batch_shrink_begin(void); +void hash_batch_shrink_end(void); #endif /* !__ASSEMBLY__ */ #endif /* __KERNEL__ */ diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c index 3fa395b3fe57..73ecd0f61acd 100644 --- a/arch/powerpc/mm/book3s64/hash_utils.c +++ b/arch/powerpc/mm/book3s64/hash_utils.c @@ -795,6 +795,9 @@ static unsigned long __init htab_get_table_size(void) } #ifdef CONFIG_MEMORY_HOTPLUG + +static DEFINE_MUTEX(hpt_resize_down_lock); + static int resize_hpt_for_hotplug(unsigned long new_mem_size, bool shrinking) { unsigned target_hpt_shift; @@ -805,7 +808,7 @@ static int resize_hpt_for_hotplug(unsigned long new_mem_size, bool shrinking) target_hpt_shift = htab_shift_for_mem_size(new_mem_size); if (shrinking) { - + int ret; /* * To avoid lots of HPT resizes if memory size is fluctuating * across a boundary, we deliberately have some hysterisis @@ -818,10 +821,20 @@ static int resize_hpt_for_hotplug(unsigned long new_mem_size, bool shrinking) if (target_hpt_shift >= ppc64_pft_size - 1) return 0; - } else if (target_hpt_shift <= ppc64_pft_size) { - return 0; + /* When batch removing entries, only resizes HPT at the end. */ + + if (!mutex_trylock(&hpt_resize_down_lock)) + return 0; + + ret = mmu_hash_ops.resize_hpt(target_hpt_shift); + + mutex_unlock(&hpt_resize_down_lock); + return ret; } + if (target_hpt_shift <= ppc64_pft_size) + return 0; + return mmu_hash_ops.resize_hpt(target_hpt_shift); } @@ -879,6 +892,32 @@ void hash_batch_expand_prepare(unsigned long newsize) break; } } + +void hash_batch_shrink_begin(void) +{ + /* Disable HPT resize-down during hot-unplug */ + mutex_lock(&hpt_resize_down_lock); +} + +void hash_batch_shrink_end(void) +{ + const u64 starting_size = ppc64_pft_size; + unsigned long newsize; + + newsize = memblock_phys_mem_size(); + /* Resize to smallest SHIFT possible */ + while (resize_hpt_for_hotplug(newsize, true) == -ENOSPC) { + newsize *= 2; + pr_warn("Hash collision while resizing HPT\n"); + + /* Do not try to resize to the starting size, or bigger value */ + if (htab_shift_for_mem_size(newsize) >= starting_size) + break; + } + + /* Re-enables HPT resize-down after hot-unplug */ + mutex_unlock(&hpt_resize_down_lock); +} #endif /* CONFIG_MEMORY_HOTPLUG */ static void __init hash_init_partition_table(phys_addr_t hash_table, diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c index 48b2cfe4ce69..44bc50d72353 100644 --- a/arch/powerpc/platforms/pseries/hotplug-memory.c +++ b/arch/powerpc/platforms/pseries/hotplug-memory.c @@ -426,6 +426,9 @@ static int dlpar_memory_remove_by_count(u32 lmbs_to_remove) return -EINVAL; } + if (!radix_enabled()) + hash_batch_shrink_begin(); + for_each_drmem_lmb(lmb) { rc = dlpar_remove_lmb(lmb); if (rc) @@ -471,6 +474,9 @@ static int dlpar_memory_remove_by_count(u32 lmbs_to_remove) rc = 0; } + if (!radix_enabled()) + hash_batch_shrink_end(); + return rc; } @@ -533,6 +539,9 @@ static int dlpar_memory_remove_by_ic(u32 lmbs_to_remove, u32 drc_index) if (lmbs_available < lmbs_to_remove) return -EINVAL; + if (!radix_enabled()) + hash_batch_shrink_begin(); + for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) { if (!(lmb->flags & DRCONF_MEM_ASSIGNED)) continue; @@ -573,6 +582,9 @@ static int dlpar_memory_remove_by_ic(u32 lmbs_to_remove, u32 drc_index) } } + if (!radix_enabled()) + hash_batch_shrink_end(); + return rc; } @@ -703,6 +715,9 @@ static int dlpar_memory_add_by_count(u32 lmbs_to_add) if (lmbs_added != lmbs_to_add) { pr_err("Memory hot-add failed, removing any added LMBs\n"); + if (!radix_enabled()) + hash_batch_shrink_begin(); + for_each_drmem_lmb(lmb) { if (!drmem_lmb_reserved(lmb)) continue; @@ -716,6 +731,10 @@ static int dlpar_memory_add_by_count(u32 lmbs_to_add) drmem_remove_lmb_reservation(lmb); } + + if (!radix_enabled()) + hash_batch_shrink_end(); + rc = -EINVAL; } else { for_each_drmem_lmb(lmb) { @@ -817,6 +836,9 @@ static int dlpar_memory_add_by_ic(u32 lmbs_to_add, u32 drc_index) if (rc) { pr_err("Memory indexed-count-add failed, removing any added LMBs\n"); + if (!radix_enabled()) + hash_batch_shrink_begin(); + for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) { if (!drmem_lmb_reserved(lmb)) continue; @@ -830,6 +852,10 @@ static int dlpar_memory_add_by_ic(u32 lmbs_to_add, u32 drc_index) drmem_remove_lmb_reservation(lmb); } + + if (!radix_enabled()) + hash_batch_shrink_end(); + rc = -EINVAL; } else { for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) {