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(p200300d82f0a7f00fad73bc9069d031f.dip0.t-ipconnect.de. [2003:d8:2f0a:7f00:fad7:3bc9:69d:31f]) by smtp.gmail.com with ESMTPSA id n5sm22627506wri.31.2021.07.20.05.11.52 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 20 Jul 2021 05:11:52 -0700 (PDT) Subject: Re: [PATCH] mm: make falutaround selectable To: Chanho Min , Andrew Morton , linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, "Kirill A . Shutemov" , Gunho Lee , Juneho Choi , Inkyu Hwang References: <20210719010845.31898-1-chanho.min@lge.com> From: David Hildenbrand Organization: Red Hat Message-ID: <42adbf38-7b1a-3039-c309-3d7023fc7c6c@redhat.com> Date: Tue, 20 Jul 2021 14:11:52 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <20210719010845.31898-1-chanho.min@lge.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org s/falutaround/faultaround/ On 19.07.21 03:08, Chanho Min wrote: > While faultaround can have performance gains, on certain platform it > increases pss and causes swap to occur more frequently. This patch allows > to unselect faultaround on platforms that do not want this behavior. > > Signed-off-by: Chanho Min > --- > mm/Kconfig | 6 ++++++ > mm/memory.c | 4 ++++ > 2 files changed, 10 insertions(+) > > diff --git a/mm/Kconfig b/mm/Kconfig > index 39a6a977537d..8f834386e7f3 100644 > --- a/mm/Kconfig > +++ b/mm/Kconfig > @@ -750,4 +750,10 @@ config ARCH_HAS_PTE_SPECIAL > config ARCH_HAS_HUGEPD > bool > > +config FAULT_AROUND > + bool "Enable fault around" > + default y > + help > + This option enables fault around. If say N, fault_around_bytes set to PAGE_SIZE > + and disables fault around. > endmenu > diff --git a/mm/memory.c b/mm/memory.c > index 10d2e4734e82..0bb037265dda 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -3500,7 +3500,11 @@ vm_fault_t finish_fault(struct vm_fault *vmf) > } > > static unsigned long fault_around_bytes __read_mostly = > +#ifdef CONFIG_FAULT_AROUND > rounddown_pow_of_two(65536); > +#else > + PAGE_SIZE; > +#endif > > #ifdef CONFIG_DEBUG_FS > static int fault_around_bytes_get(void *data, u64 *val) > -- Thanks, David / dhildenb