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From: Mika Kuoppala <mika.kuoppala@linux.intel.com>
To: Chris Wilson <chris@chris-wilson.co.uk>, intel-gfx@lists.freedesktop.org
Cc: igt-dev@lists.freedesktop.org, matthew.auld@intel.com
Subject: Re: [igt-dev] [Intel-gfx] [PATCH i-g-t 1/3] i915/gem_userptr_blits: Only mlock the memfd once, not the arena
Date: Wed, 16 Jan 2019 11:47:27 +0200	[thread overview]
Message-ID: <87r2ddx7bk.fsf@gaia.fi.intel.com> (raw)
In-Reply-To: <20190116093509.30195-1-chris@chris-wilson.co.uk>

Chris Wilson <chris@chris-wilson.co.uk> writes:

> We multiply the memfd 64k to create a 2G arena which we then attempt to
> write into after marking read-only. Howver, when it comes to unlock the

s/Howver/However

> arena after the test, performance tanks as the kernel tries to resolve
> the 64k repeated mappings onto the same set of pages. (Must not be a
> very common operation!) We can get away with just mlocking the backing
> store to prevent its eviction, which should prevent the arena mapping
> from being freed as well.

hmm should. How are they bound?

-Mika

>
> References: https://bugs.freedesktop.org/show_bug.cgi?id=108887
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> ---
>  tests/i915/gem_userptr_blits.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/tests/i915/gem_userptr_blits.c b/tests/i915/gem_userptr_blits.c
> index 909dd19df..c4e60ba92 100644
> --- a/tests/i915/gem_userptr_blits.c
> +++ b/tests/i915/gem_userptr_blits.c
> @@ -1124,7 +1124,7 @@ static void test_readonly(int i915)
>  		*(uint32_t *)(space + offset) = offset;
>  	}
>  	igt_assert_eq_u32(*(uint32_t *)pages, (uint32_t)(total - sz));
> -	igt_assert(mlock(space, total) == 0);
> +	igt_assert(mlock(pages, sz) == 0);
>  	close(memfd);
>  
>  	/* Check we can create a normal userptr bo wrapping the wrapper */
> @@ -1176,6 +1176,7 @@ static void test_readonly(int i915)
>  	}
>  	igt_waitchildren();
>  
> +	munlock(pages, sz);
>  	munmap(space, total);
>  	munmap(pages, sz);
>  }
> -- 
> 2.20.1
>
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
_______________________________________________
igt-dev mailing list
igt-dev@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/igt-dev

WARNING: multiple messages have this Message-ID (diff)
From: Mika Kuoppala <mika.kuoppala@linux.intel.com>
To: Chris Wilson <chris@chris-wilson.co.uk>, intel-gfx@lists.freedesktop.org
Cc: igt-dev@lists.freedesktop.org, matthew.auld@intel.com
Subject: Re: [PATCH i-g-t 1/3] i915/gem_userptr_blits: Only mlock the memfd once, not the arena
Date: Wed, 16 Jan 2019 11:47:27 +0200	[thread overview]
Message-ID: <87r2ddx7bk.fsf@gaia.fi.intel.com> (raw)
In-Reply-To: <20190116093509.30195-1-chris@chris-wilson.co.uk>

Chris Wilson <chris@chris-wilson.co.uk> writes:

> We multiply the memfd 64k to create a 2G arena which we then attempt to
> write into after marking read-only. Howver, when it comes to unlock the

s/Howver/However

> arena after the test, performance tanks as the kernel tries to resolve
> the 64k repeated mappings onto the same set of pages. (Must not be a
> very common operation!) We can get away with just mlocking the backing
> store to prevent its eviction, which should prevent the arena mapping
> from being freed as well.

hmm should. How are they bound?

-Mika

>
> References: https://bugs.freedesktop.org/show_bug.cgi?id=108887
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> ---
>  tests/i915/gem_userptr_blits.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/tests/i915/gem_userptr_blits.c b/tests/i915/gem_userptr_blits.c
> index 909dd19df..c4e60ba92 100644
> --- a/tests/i915/gem_userptr_blits.c
> +++ b/tests/i915/gem_userptr_blits.c
> @@ -1124,7 +1124,7 @@ static void test_readonly(int i915)
>  		*(uint32_t *)(space + offset) = offset;
>  	}
>  	igt_assert_eq_u32(*(uint32_t *)pages, (uint32_t)(total - sz));
> -	igt_assert(mlock(space, total) == 0);
> +	igt_assert(mlock(pages, sz) == 0);
>  	close(memfd);
>  
>  	/* Check we can create a normal userptr bo wrapping the wrapper */
> @@ -1176,6 +1176,7 @@ static void test_readonly(int i915)
>  	}
>  	igt_waitchildren();
>  
> +	munlock(pages, sz);
>  	munmap(space, total);
>  	munmap(pages, sz);
>  }
> -- 
> 2.20.1
>
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx

  parent reply	other threads:[~2019-01-16  9:47 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-16  9:35 [igt-dev] [PATCH i-g-t 1/3] i915/gem_userptr_blits: Only mlock the memfd once, not the arena Chris Wilson
2019-01-16  9:35 ` Chris Wilson
2019-01-16  9:35 ` [igt-dev] [PATCH i-g-t 2/3] i915/gem_cpu_reloc: Use a self-modifying chained batch Chris Wilson
2019-01-16  9:35   ` Chris Wilson
2019-01-16 14:22   ` [igt-dev] [Intel-gfx] " Mika Kuoppala
2019-01-16 14:22     ` Mika Kuoppala
2019-01-16 14:30     ` [igt-dev] [Intel-gfx] " Chris Wilson
2019-01-16 14:30       ` Chris Wilson
2019-01-16 14:49       ` [igt-dev] [Intel-gfx] " Mika Kuoppala
2019-01-16 14:49         ` Mika Kuoppala
2019-01-16  9:35 ` [igt-dev] [PATCH i-g-t 3/3] igt/drv_missed_irq: Skip if the kernel reports no rings available to test Chris Wilson
2019-01-16  9:35   ` Chris Wilson
2019-01-16 14:30   ` [igt-dev] [Intel-gfx] " Mika Kuoppala
2019-01-16 14:30     ` Mika Kuoppala
2019-01-16  9:47 ` Mika Kuoppala [this message]
2019-01-16  9:47   ` [PATCH i-g-t 1/3] i915/gem_userptr_blits: Only mlock the memfd once, not the arena Mika Kuoppala
2019-01-16  9:58   ` [Intel-gfx] " Chris Wilson
2019-01-16  9:58     ` Chris Wilson
2019-01-16 10:35     ` [igt-dev] [Intel-gfx] " Mika Kuoppala
2019-01-16 10:35       ` Mika Kuoppala
2019-01-16 10:46       ` [igt-dev] [Intel-gfx] " Chris Wilson
2019-01-16 10:46         ` Chris Wilson
2019-01-16 10:27 ` [igt-dev] ✓ Fi.CI.BAT: success for series starting with [i-g-t,1/3] " Patchwork
2019-01-16 11:58 ` [igt-dev] ✓ Fi.CI.IGT: " Patchwork

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