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From:   Kuo-Hsin Yang <vovoy@chromium.org>
Date:   Tue, 6 Nov 2018 19:49:46 +0800
Message-ID: <CAEHM+4rEibRffjO0dDncqRpc++8cAOpk-E0PNMW-4E-cMjkNnQ@mail.gmail.com>
Subject: Re: [PATCH v6] mm, drm/i915: mark pinned shmemfs pages as unevictable
To:     Chris Wilson <chris@chris-wilson.co.uk>
Cc:     intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org,
        Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Dave Hansen <dave.hansen@intel.com>,
        Michal Hocko <mhocko@suse.com>
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On Tue, Nov 6, 2018 at 7:07 PM Chris Wilson <chris@chris-wilson.co.uk> wrote:
> This gave disappointing syslatency results until I put a cond_resched()
> here and moved the one in put_pages_gtt to before the page alloc, see
> https://patchwork.freedesktop.org/patch/260332/
>
> The last really nasty wart for syslatency is the spin in
> i915_gem_shrinker, for which I'm investigating
> https://patchwork.freedesktop.org/patch/260365/
>
> All 3 patches together give very reasonable syslatency results! (So
> good that it's time to find a new worst case scenario!)
>
> The challenge for the patch as it stands, is who lands it? We can take
> it through drm-intel (for merging in 4.21) but need Andrew's ack on top
> of all to agree with that path. Or we split the patch and only land the
> i915 portion once we backmerge the mm tree. I think pushing the i915
> portion through the mm tree is going to cause the most conflicts, so
> would recommend against that.

Splitting the patch and landing the mm part first sounds reasonable to me.