Re: [PATCH v3] mm/zswap: move to use crypto_acomp API for hardware acceleration

[Herbert Xu]

On Fri, Jun 26, 2020 at 07:09:03PM +1200, Barry Song wrote:
>
> +	mutex_lock(&acomp_ctx->mutex);
> +
> +	src = kmap(page);
> +	dst = acomp_ctx->dstmem;
> +	sg_init_one(&input, src, PAGE_SIZE);
> +	/* zswap_dstmem is of size (PAGE_SIZE * 2). Reflect same in sg_list */
> +	sg_init_one(&output, dst, PAGE_SIZE * 2);
> +	acomp_request_set_params(acomp_ctx->req, &input, &output, PAGE_SIZE, dlen);
> +	ret = crypto_wait_req(crypto_acomp_compress(acomp_ctx->req), &acomp_ctx->wait);
> +	dlen = acomp_ctx->req->dlen;
> +	kunmap(page);

Waiting on an async request like this is just silly.  This defeats
the whole purpose of having a fallback.

Cheers,
-- 
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
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