Re: [PATCH RFC v2 0/5] zram: Allow zcomps to manage their own streams

[Jihan LIN]

Hi Sergey,

On Wed, Mar 11, 2026 at 4:52 PM Sergey Senozhatsky
<senozhatsky@xxxxxxxxxxxx> wrote:
> So does such a hardware exist?

Yes, there are a few examples, as far as I know.

LZ4 is relevant here because it is widely used, and decompression is
already very fast on the CPU. So a compression-only accelerator makes
sense.

HiSilicon has hisi_zip in its server SoCs. For LZ4, hisi_zip offloads
compression only, with decompression handled in software[1].

I also found some out-of-tree examples, such as qpace_drv for SM8845 in
OnePlus's tree[2] and mtk_hwz for some MediaTek SoCs from Samsung[3].

These examples suggest a similar setup: queue-based hardware, while
software (or synchronous paths) is still used for some decompression
paths. These are the kinds of devices I had in mind, and deeper hardware
queues do not fit well into the current model. Well, I don't have any of
these on hand yet, but this is a kind of use case behind this series.


[1]: https://lore.kernel.org/all/20260117023435.1616703-1-huangchenghai2@xxxxxxxxxx/
[2]: https://github.com/OnePlusOSS/android_kernel_oneplus_sm8845/tree/ecfc67b9e933937140df7a1cf39060de8dbd11be/drivers/block/zram
[3]: https://github.com/samsung-mediatek/android_kernel_device_modules-6.12/tree/4749bfe7783c045f53c50160e05b67a9a2acc3f4/drivers/misc/mediatek/mtk_zram