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Message-ID: <c12ada0c-0c59-4be7-979f-0b99c7da36b8@collabora.com>
Date: Sun, 24 Mar 2024 22:56:24 +0500
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Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>,
 Andrew Morton <akpm@linux-foundation.org>,
 David Hildenbrand <david@redhat.com>, Nico Pache <npache@redhat.com>,
 Muchun Song <muchun.song@linux.dev>
Subject: Re: [PATCH] selftests/mm: run_vmtests.sh: Fix hugetlb mem size
 calculation
To: peterx@redhat.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org
References: <20240321215047.678172-1-peterx@redhat.com>
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From: Muhammad Usama Anjum <usama.anjum@collabora.com>
In-Reply-To: <20240321215047.678172-1-peterx@redhat.com>
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On 3/22/24 2:50 AM, peterx@redhat.com wrote:
> From: Peter Xu <peterx@redhat.com>
> 
> The script calculates a mininum required size of hugetlb memories, but
> it'll stop working with <1MB huge page sizes, reporting all zeros even if
> huge pages are available.
> 
> In reality, the calculation doesn't really need to be as comlicated either.
> Make it simpler and work for KB-level hugepages too.
> 
> Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
> Cc: David Hildenbrand <david@redhat.com>
> Cc: Nico Pache <npache@redhat.com>
> Cc: Muchun Song <muchun.song@linux.dev>
> Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com>

> ---
>  tools/testing/selftests/mm/run_vmtests.sh | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/testing/selftests/mm/run_vmtests.sh b/tools/testing/selftests/mm/run_vmtests.sh
> index c2c542fe7b17..b1b78e45d613 100755
> --- a/tools/testing/selftests/mm/run_vmtests.sh
> +++ b/tools/testing/selftests/mm/run_vmtests.sh
> @@ -152,9 +152,13 @@ done < /proc/meminfo
>  # both of these requirements into account and attempt to increase
>  # number of huge pages available.
>  nr_cpus=$(nproc)
> -hpgsize_MB=$((hpgsize_KB / 1024))
> -half_ufd_size_MB=$((((nr_cpus * hpgsize_MB + 127) / 128) * 128))
> -needmem_KB=$((half_ufd_size_MB * 2 * 1024))
> +uffd_min_KB=$((hpgsize_KB * nr_cpus * 2))
> +hugetlb_min_KB=$((256 * 1024))
> +if [[ $uffd_min_KB -gt $hugetlb_min_KB ]]; then
> +	needmem_KB=$uffd_min_KB
> +else
> +	needmem_KB=$hugetlb_min_KB
> +fi
>  
>  # set proper nr_hugepages
>  if [ -n "$freepgs" ] && [ -n "$hpgsize_KB" ]; then

-- 
BR,
Muhammad Usama Anjum