On 2020-05-19 21:46:06 [+0000], Song Bao Hua wrote: > Hi Luis, > In the below patch, in order to use the acomp APIs to leverage the power of hardware compressors. I have moved to mutex: > https://marc.info/?l=linux-crypto-vger&m=158941285830302&w=2 > https://marc.info/?l=linux-crypto-vger&m=158941287930311&w=2 > > so once we get some progress on that one, I guess we don't need a special patch for RT any more. If you convert this way from the current concept then we could drop it from the series. The second patch shows the following hunk: |@@ -1075,11 +1124,20 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset, | | /* compress */ | dst = get_cpu_var(zswap_dstmem); | acomp_ctx = *this_cpu_ptr(entry->pool->acomp_ctx); | put_cpu_var(zswap_dstmem); So here you get per-CPU version of `dst' and `acomp_ctx' and then allow preemption again. | mutex_lock(&acomp_ctx->mutex); | | src = kmap(page); | 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); and here you use `dst' and `acomp_ctx' after the preempt_disable() has been dropped so I don't understand why you used get_cpu_var(). It is either protected by the mutex and doesn't require get_cpu_var() or it isn't (and should have additional protection). | 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); | | if (ret) { | ret = -EINVAL; | goto put_dstmem; | Sebastian
