From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from s3.sipsolutions.net ([5.9.151.49]:56305 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752475AbcJROQi (ORCPT ); Tue, 18 Oct 2016 10:16:38 -0400 Message-ID: <1476800194.6425.35.camel@sipsolutions.net> (sfid-20161018_161642_416941_DE3E9E8D) Subject: Re: [RFC PATCH 2/2] mac80211: aes_ccm: cache AEAD request structures per CPU From: Johannes Berg To: Ard Biesheuvel , linux-wireless@vger.kernel.org, netdev@vger.kernel.org Cc: herbert@gondor.apana.org.au, j@w1.fi, luto@amacapital.net Date: Tue, 18 Oct 2016 16:16:34 +0200 In-Reply-To: <1476799713-16188-3-git-send-email-ard.biesheuvel@linaro.org> (sfid-20161018_160844_561124_0C52FCB9) References: <1476799713-16188-1-git-send-email-ard.biesheuvel@linaro.org> <1476799713-16188-3-git-send-email-ard.biesheuvel@linaro.org> (sfid-20161018_160844_561124_0C52FCB9) Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Tue, 2016-10-18 at 15:08 +0100, Ard Biesheuvel wrote: >  > + aead_req = *this_cpu_ptr(ccmp->reqs); > + if (!aead_req) { > + aead_req = kzalloc(reqsize + CCM_AAD_LEN, GFP_ATOMIC); > + if (!aead_req) > + return -ENOMEM; > + *this_cpu_ptr(ccmp->reqs) = aead_req; > + aead_request_set_tfm(aead_req, ccmp->tfm); > + } Hmm. Is it really worth having a per-CPU variable for each possible key? You could have a large number of those (typically three when you're a client on an AP, and 1 + 1 for each client when you're the AP). Would it be so bad to have to set the TFM every time (if that's even possible), and just have a single per-CPU cache? johannes