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[2003:cb:c700:2400:6b79:2aa:9602:7016]) by smtp.gmail.com with ESMTPSA id p17-20020a056000019100b002fda1b12a0bsm30878929wrx.2.2023.05.02.04.27.41 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 02 May 2023 04:27:42 -0700 (PDT) Message-ID: <5574983a-3b32-f519-9012-a66b319fc6a8@redhat.com> Date: Tue, 2 May 2023 13:27:41 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.10.0 Subject: Re: [PATCH 1/1] mm: change per-VMA lock statistics to be disabled by default Content-Language: en-US To: Suren Baghdasaryan , akpm@linux-foundation.org Cc: torvalds@linux-foundation.org, lstoakes@gmail.com, vbabka@suse.cz, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@android.com References: <20230428173533.18158-1-surenb@google.com> From: David Hildenbrand Organization: Red Hat In-Reply-To: <20230428173533.18158-1-surenb@google.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 28.04.23 19:35, Suren Baghdasaryan wrote: > Change CONFIG_PER_VMA_LOCK_STATS to be disabled by default, as most > users don't need it. Add configuration help to clarify its usage. > > Fixes: 52f238653e45 ("mm: introduce per-VMA lock statistics") > Suggested-by: Linus Torvalds > Signed-off-by: Suren Baghdasaryan > --- > mm/Kconfig.debug | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug > index 6dae63b46368..a925415b4d10 100644 > --- a/mm/Kconfig.debug > +++ b/mm/Kconfig.debug > @@ -274,6 +274,12 @@ config DEBUG_KMEMLEAK_AUTO_SCAN > config PER_VMA_LOCK_STATS > bool "Statistics for per-vma locks" > depends on PER_VMA_LOCK > - default y > help > - Statistics for per-vma locks. > + Say Y here to enable success, retry and failure counters of page > + faults handled under protection of per-vma locks. When enabled, the > + counters are exposed in /proc/vmstat. This information is useful for > + kernel developers to evaluate effectiveness of per-vma locks and to > + identify pathological cases. Counting these events introduces a small > + overhead in the page fault path. > + > + If in doubt, say N. Reviewed-by: David Hildenbrand -- Thanks, David / dhildenb