From: Michal Hocko <mhocko@kernel.org>
To: Cannon Matthews <cannonmatthews@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Mike Kravetz <mike.kravetz@oracle.com>,
Nadia Yvette Chambers <nyc@holomorphy.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
andreslc@google.com, pfeiner@google.com, dmatlack@google.com,
gthelen@google.com
Subject: Re: [PATCH v2] mm: hugetlb: don't zero 1GiB bootmem pages.
Date: Thu, 12 Jul 2018 09:48:03 +0200 [thread overview]
Message-ID: <20180712074803.GB32648@dhcp22.suse.cz> (raw)
In-Reply-To: <20180711213313.92481-1-cannonmatthews@google.com>
On Wed 11-07-18 14:33:13, Cannon Matthews wrote:
> 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.
>
> 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 <cannonmatthews@google.com>
Thanks for the updated version.
Acked-by: Michal Hocko <mhocko@suse.com>
> ---
> v2: removed the memset of the huge_bootmem_page area and added
> INIT_LIST_HEAD instead.
>
> mm/hugetlb.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 3612fbb32e9d..488330f23f04 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) {
> @@ -2119,6 +2119,7 @@ int __alloc_bootmem_huge_page(struct hstate *h)
> found:
> BUG_ON(!IS_ALIGNED(virt_to_phys(m), huge_page_size(h)));
> /* Put them into a private list first because mem_map is not up yet */
> + INIT_LIST_HEAD(&m->list);
> list_add(&m->list, &huge_boot_pages);
> m->hstate = h;
> return 1;
> --
> 2.18.0.203.gfac676dfb9-goog
--
Michal Hocko
SUSE Labs
prev parent reply other threads:[~2018-07-12 7:48 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-11 21:33 [PATCH v2] mm: hugetlb: don't zero 1GiB bootmem pages Cannon Matthews
2018-07-11 21:56 ` Mike Kravetz
2018-07-12 7:48 ` Michal Hocko [this message]
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