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Date: Sun, 24 Dec 2023 21:21:03 -0800 (PST)
From: David Rientjes <rientjes@google.com>
To: Gang Li <ligang.bdlg@bytedance.com>
cc: Mike Kravetz <mike.kravetz@oracle.com>, Gang Li <gang.li@linux.dev>, 
    David Hildenbrand <david@redhat.com>, Muchun Song <muchun.song@linux.dev>, 
    Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org, 
    linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH v2 0/5] hugetlb: parallelize hugetlb page init on
 boot
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On Thu, 21 Dec 2023, David Rientjes wrote:

> > Hi,
> > 
> > On 2023/12/13 08:10, David Rientjes wrote:
> > > On 6.6 I measured "hugepagesz=1G hugepages=11776" on as 12TB host to be
> > > 77s this time around.
> > 
> > Thanks for your test! Is this the total kernel boot time, or just the
> > hugetlb initialization time?
> > 
> 
> Ah, sorry for not being specific.  It's just the hugetlb preallocation of 
> 11776 1GB hugetlb pages, total boot takes a few more minutes.
> 

I had to apply this to get the patch series to compile on 6.7-rc7:

diff --git a/kernel/padata.c b/kernel/padata.c
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -485,7 +485,7 @@ void __init padata_do_multithreaded(struct padata_mt_job *job)
 	struct padata_work my_work, *pw;
 	struct padata_mt_job_state ps;
 	LIST_HEAD(works);
-	int nworks, nid;
+	int nworks, nid = 0;
 
 	if (job->size == 0)
 		return;
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3300,7 +3300,7 @@ int alloc_bootmem_huge_page(struct hstate *h, int nid)
 int __alloc_bootmem_huge_page(struct hstate *h, int nid)
 {
 	struct huge_bootmem_page *m = NULL; /* initialize for clang */
-	int nr_nodes, node;
+	int nr_nodes, node = NUMA_NO_NODE;
 
 	/* do node specific alloc */
 	if (nid != NUMA_NO_NODE) {

With that, I compared "hugepagesz=1G hugepages=11776" before and after on 
a 12TB host with eight NUMA nodes.

Compared to 77s of total initialization time before, with this series I 
measured 18.3s.

Feel free to add this into the changelog once the initialization issues 
are fixed up and I'm happy to ack it.

Thanks!