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Date:   Tue, 21 Jun 2022 19:39:21 +0300
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Subject: Re: [PATCH v6 17/22] drm/shmem-helper: Add generic memory shrinker
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To:     Rob Clark <robdclark@gmail.com>,
        Dmitry Osipenko <dmitry.osipenko@collabora.com>
Cc:     David Airlie <airlied@linux.ie>, Gerd Hoffmann <kraxel@redhat.com>,
        Gurchetan Singh <gurchetansingh@chromium.org>,
        Chia-I Wu <olvaffe@gmail.com>, Daniel Vetter <daniel@ffwll.ch>,
        Daniel Almeida <daniel.almeida@collabora.com>,
        Gert Wollny <gert.wollny@collabora.com>,
        Gustavo Padovan <gustavo.padovan@collabora.com>,
        Daniel Stone <daniel@fooishbar.org>,
        Tomeu Vizoso <tomeu.vizoso@collabora.com>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Maxime Ripard <mripard@kernel.org>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        Rob Herring <robh@kernel.org>,
        Steven Price <steven.price@arm.com>,
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        Tomasz Figa <tfiga@chromium.org>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
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        Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
        Rodrigo Vivi <rodrigo.vivi@intel.com>,
        Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>,
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References: <20220526235040.678984-1-dmitry.osipenko@collabora.com>
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 <CAF6AEGt=EqeF+3UaYjxQCCFEabRFJwLbiWN9brGveYoHTYyZ7w@mail.gmail.com>
From:   Dmitry Osipenko <digetx@gmail.com>
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20.06.2022 18:37, Rob Clark пишет:
>> +static unsigned long
>> +drm_gem_shmem_shrinker_scan_objects(struct shrinker *shrinker,
>> +                                   struct shrink_control *sc)
>> +{
>> +       unsigned long nr_to_scan = sc->nr_to_scan;
>> +       bool lock_contention = false;
>> +       unsigned long freed;
>> +
>> +       /* purge as many objects as we can */
>> +       freed = drm_gem_shmem_shrinker_run_objects_scan(shrinker, nr_to_scan,
>> +                                                       &lock_contention, false);
>> +
>> +       /* evict as many objects as we can */
>> +       if (freed < nr_to_scan)
> oh, one other small note, both in scan_objects() and count_objects(),
> you should check that get_nr_swap_pages()>0 before counting
> evictable/willneed objects.  (And you probably want to keep separate
> LRUs for dontneed vs willneed to accomplish that.)  At least for CrOS,
> inside the VM there is no swap enabled (but instead we rely on zram
> swap in the host.. plus vm-balloon to balance memory pressure between
> host and guest)

Noted, thank you!