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Fri, 14 Aug 2020 10:20:16 -0700 (PDT) From: Arvind Sankar X-Google-Original-From: Arvind Sankar Date: Fri, 14 Aug 2020 13:20:14 -0400 To: Linus Torvalds Cc: Andrew Morton , 4sschmid@informatik.uni-hamburg.de, Gao Xiang , Greg Kroah-Hartman , Linux-MM , Ingo Molnar , mm-commits@vger.kernel.org, Arvind Sankar , terrelln@fb.com, yann.collet.73@gmail.com Subject: Re: [patch 090/165] lz4: fix kernel decompression speed Message-ID: <20200814172014.GA4106860@rani.riverdale.lan> References: <20200811182949.e12ae9a472e3b5e27e16ad6c@linux-foundation.org> <20200812013500.TPqi6kXv2%akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: CB9A38014BEA X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam02 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Aug 12, 2020 at 10:54:08AM -0700, Linus Torvalds wrote: > On Tue, Aug 11, 2020 at 6:35 PM Andrew Morton wrote: > > > > From: Nick Terrell > > Subject: lz4: fix kernel decompression speed > > > > This patch replaces all memcpy() calls with LZ4_memcpy() which calls > > __builtin_memcpy() so the compiler can inline it. > > Wasn't this LZ4_memcpy() wrapper made unnecessary by just making > memcpy() work properly on its own? > > So I'm dropping this patch. > > If it turns out that I mis-remembered (or mis-understood), please re-send. Nick? > > Linus I assume you're referring to my patch [0]. It hasn't been picked up yet, and it is only for x86. I think Nick wanted his patch to be merged as well [1], because it will also address other architectures (eg it looks like at least s390 LZ4 probably has the same issue), and is already in upstream LZ4. Thanks. [0] https://lore.kernel.org/lkml/20200804234817.3922187-1-nivedita@alum.mit.edu/ [1] https://lore.kernel.org/lkml/3961E1BD-8F58-4240-A3B3-B7032A405B42@fb.com/