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Date: Tue, 26 Mar 2024 12:03:40 -0300
From: Jason Gunthorpe <jgg@ziepe.ca>
To: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: kernel@collabora.com, iommu@lists.linux.dev,
	linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org,
	Kevin Tian <kevin.tian@intel.com>, Shuah Khan <shuah@kernel.org>
Subject: Re: [PATCH] selftests: iommu: add config needed for iommufd_fail_nth
Message-ID: <20240326150340.GE8419@ziepe.ca>
References: <20240325090048.1423908-1-usama.anjum@collabora.com>
 <31fcc276-acd6-4277-bd6c-4a871c7fb28a@collabora.com>
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In-Reply-To: <31fcc276-acd6-4277-bd6c-4a871c7fb28a@collabora.com>

On Tue, Mar 26, 2024 at 06:09:34PM +0500, Muhammad Usama Anjum wrote:
> Even after applying this config patch and following snippet (which doesn't
> terminate the program if mmap doesn't allocate exactly as the hint), I'm
> finding failed tests.
> 
> @@ -1746,7 +1748,7 @@ FIXTURE_SETUP(iommufd_dirty_tracking)
>         assert((uintptr_t)self->buffer % HUGEPAGE_SIZE == 0);
>         vrc = mmap(self->buffer, variant->buffer_size, PROT_READ | PROT_WRITE,
>                    mmap_flags, -1, 0);
> -       assert(vrc == self->buffer);
> +       assert(vrc == self->buffer);// ???
> 
> On x86:
> # Totals: pass:176 fail:4 xfail:0 xpass:0 skip:0 error:0
> On ARM64:
> # Totals: pass:166 fail:14 xfail:0 xpass:0 skip:0 error:0
> 
> The log files are attached.

You probably don't have enough transparent huge pages available to the process

      echo 1024 > /proc/sys/vm/nr_hugepages

Jason