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[46.139.12.213]) by smtp.gmail.com with ESMTPSA id c63sm762243wma.29.2019.04.29.13.05.56 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 29 Apr 2019 13:05:57 -0700 (PDT) Date: Mon, 29 Apr 2019 22:05:54 +0200 From: Ingo Molnar To: Atish Patra Cc: linux-kernel@vger.kernel.org, Albert Ou , Andrew Morton , Anup Patel , Borislav Petkov , Changbin Du , Gary Guo , "H. Peter Anvin" , Ingo Molnar , Kees Cook , linux-mm@kvack.org, linux-riscv@lists.infradead.org, Luc Van Oostenryck , Palmer Dabbelt , Thomas Gleixner , Vlastimil Babka , "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" , Christoph Hellwig Subject: Re: [PATCH v2 1/3] x86: Move DEBUG_TLBFLUSH option. Message-ID: <20190429200554.GA102486@gmail.com> References: <20190429195759.18330-1-atish.patra@wdc.com> <20190429195759.18330-2-atish.patra@wdc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190429195759.18330-2-atish.patra@wdc.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Atish Patra wrote: > CONFIG_DEBUG_TLBFLUSH was added in 'commit 3df3212f9722 ("x86/tlb: add > tlb_flushall_shift knob into debugfs")' to support tlb_flushall_shift > knob. The knob was removed in 'commit e9f4e0a9fe27 ("x86/mm: Rip out > complicated, out-of-date, buggy TLB flushing")'. However, the debug > option was never removed from Kconfig. It was reused in commit > '9824cf9753ec ("mm: vmstats: tlb flush counters")' but the commit text > was never updated accordingly. Please, when you mention several commits, put them into new lines to make it readable, i.e.: 3df3212f9722 ("x86/tlb: add tlb_flushall_shift knob into debugfs") etc. > Update the Kconfig option description as per its current usage. > > Take this opprtunity to make this kconfig option a common option as it > touches the common vmstat code. Introduce another arch specific config > HAVE_ARCH_DEBUG_TLBFLUSH that can be selected to enable this config. "opprtunity"? > +config HAVE_ARCH_DEBUG_TLBFLUSH > + bool > + depends on DEBUG_KERNEL > + > +config DEBUG_TLBFLUSH > + bool "Save tlb flush statstics to vmstat" > + depends on HAVE_ARCH_DEBUG_TLBFLUSH > + help > + > + Add tlbflush statstics to vmstat. It is really helpful understand tlbflush > + performance and behavior. It should be enabled only for debugging purpose > + by individual architectures explicitly by selecting HAVE_ARCH_DEBUG_TLBFLUSH. "statstics"?? Please put a spell checker into your workflow or read what you are writing ... Thanks, Ingo