Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Wed, 30 Sep 2020 12:43:39 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Mike Rapoport <rppt@kernel.org>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Andy Lutomirski <luto@kernel.org>,
        Arnd Bergmann <arnd@arndb.de>, Borislav Petkov <bp@alien8.de>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Christopher Lameter <cl@linux.com>,
        Dan Williams <dan.j.williams@intel.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        David Hildenbrand <david@redhat.com>,
        Elena Reshetova <elena.reshetova@intel.com>,
        "H. Peter Anvin" <hpa@zytor.com>, Idan Yaniv <idan.yaniv@ibm.com>,
        Ingo Molnar <mingo@redhat.com>,
        James Bottomley <jejb@linux.ibm.com>,
        "Kirill A. Shutemov" <kirill@shutemov.name>,
        Matthew Wilcox <willy@infradead.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Mike Rapoport <rppt@linux.ibm.com>,
        Michael Kerrisk <mtk.manpages@gmail.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Shuah Khan <shuah@kernel.org>, Tycho Andersen <tycho@tycho.ws>,
        Will Deacon <will@kernel.org>, linux-api@vger.kernel.org,
        linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
        linux-nvdimm@lists.01.org, linux-riscv@lists.infradead.org,
        x86@kernel.org, songliubraving@fb.com
Subject: Re: [PATCH v6 5/6] mm: secretmem: use PMD-size pages to amortize
 direct map fragmentation
Message-ID: <20200930104339.GK2611@hirez.programming.kicks-ass.net>
References: <20200924132904.1391-1-rppt@kernel.org>
 <20200924132904.1391-6-rppt@kernel.org>
 <20200925074125.GQ2628@hirez.programming.kicks-ass.net>
 <20200929130529.GE2142832@kernel.org>
 <20200929141216.GO2628@hirez.programming.kicks-ass.net>
 <20200930102031.GJ2142832@kernel.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20200930102031.GJ2142832@kernel.org>
Precedence: bulk

On Wed, Sep 30, 2020 at 01:20:31PM +0300, Mike Rapoport wrote:

> I tried to dig the regression report in the mailing list, and the best I
> could find is
> 
> https://lore.kernel.org/lkml/20190823052335.572133-1-songliubraving@fb.com/
> 
> which does not mention the actual performance regression but it only
> complaints about kernel text mapping being split into 4K pages.
> 
> Any chance you have the regression report handy? 

I think the saga started here:

 20190820075128.2912224-1-songliubraving@fb.com
 20190820202314.1083149-1-songliubraving@fb.com
 20190823052335.572133-1-songliubraving@fb.com

After that Thomas did the patch I referred to earlier and I endeavoured
to rewrite x86-ftrace.

I added Song to CC, maybe he can remember more.