From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-f200.google.com (mail-qk0-f200.google.com [209.85.220.200]) by kanga.kvack.org (Postfix) with ESMTP id 67D456B0005 for ; Tue, 10 Jul 2018 14:49:23 -0400 (EDT) Received: by mail-qk0-f200.google.com with SMTP id b185-v6so28383184qkg.19 for ; Tue, 10 Jul 2018 11:49:23 -0700 (PDT) Received: from mail-sor-f73.google.com (mail-sor-f73.google.com. [209.85.220.73]) by mx.google.com with SMTPS id u1-v6sor3626963qvh.88.2018.07.10.11.49.21 for (Google Transport Security); Tue, 10 Jul 2018 11:49:21 -0700 (PDT) MIME-Version: 1.0 Date: Tue, 10 Jul 2018 11:49:03 -0700 Message-Id: <20180710184903.68239-1-cannonmatthews@google.com> Subject: [PATCH] mm: hugetlb: don't zero 1GiB bootmem pages. From: Cannon Matthews Content-Type: text/plain; charset="UTF-8" Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton , Mike Kravetz , Nadia Yvette Chambers Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, andreslc@google.com, pfeiner@google.com, dmatlack@google.com, gthelen@google.com, Cannon Matthews When using 1GiB pages during early boot, use the new memblock_virt_alloc_try_nid_raw() function to allocate memory without zeroing it. Zeroing out hundreds or thousands of GiB in a single core memset() call is very slow, and can make early boot last upwards of 20-30 minutes on multi TiB machines. To be safe, still zero the first sizeof(struct boomem_huge_page) bytes since this is used a temporary storage place for this info until gather_bootmem_prealloc() processes them later. The rest of the memory does not need to be zero'd as the hugetlb pages are always zero'd on page fault. Tested: Booted with ~3800 1G pages, and it booted successfully in roughly the same amount of time as with 0, as opposed to the 25+ minutes it would take before. Signed-off-by: Cannon Matthews --- mm/hugetlb.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 3612fbb32e9d..c93a2c77e881 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -2101,7 +2101,7 @@ int __alloc_bootmem_huge_page(struct hstate *h) for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) { void *addr; - addr = memblock_virt_alloc_try_nid_nopanic( + addr = memblock_virt_alloc_try_nid_raw( huge_page_size(h), huge_page_size(h), 0, BOOTMEM_ALLOC_ACCESSIBLE, node); if (addr) { @@ -2109,7 +2109,12 @@ int __alloc_bootmem_huge_page(struct hstate *h) * Use the beginning of the huge page to store the * huge_bootmem_page struct (until gather_bootmem * puts them into the mem_map). + * + * memblock_virt_alloc_try_nid_raw returns non-zero'd + * memory so zero out just enough for this struct, the + * rest will be zero'd on page fault. */ + memset(addr, 0, sizeof(struct huge_bootmem_page)); m = addr; goto found; } -- 2.18.0.203.gfac676dfb9-goog