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b=UGJywINqQlP26oRRuhAQ30+JcvUZC+z/ghQV8udAX6B0OfOCG6e8Ee3Icuh7OauiH brY18ro3p1vlEEGM50AhTaFe1ByWTrAJrlkI+Vc38HMnwRyHBXLkBfwCUD7MKp+y1J wgkXJeBumJzByhtc7X5Nj8HKhbkG5+AfLAmweLY/u06veL1F8Lwy+yUwK+YFJp3deh eklC+rPkPsTDk+n5Ndj2/qMIzz7E5YVB0PVzHle+JUwuGqUOGr+SYadyycXj6/6TRQ gYM1iEnTf1YtwkHa+FFOYCTMh0B0qwRDcQgCJavPQE53rxebxOlIU+X92AH9h5z39s ingEnw2wBQ8eQ== Message-ID: <8e164e8b-1748-4570-822c-b973770e8fb7@kernel.org> Date: Mon, 19 Jan 2026 11:20:44 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 7/7] mm: make PT_RECLAIM depends on MMU_GATHER_RCU_TABLE_FREE To: Qi Zheng , will@kernel.org, aneesh.kumar@kernel.org, npiggin@gmail.com, peterz@infradead.org, dev.jain@arm.com, akpm@linux-foundation.org, ioworker0@gmail.com, linmag7@gmail.com Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-alpha@vger.kernel.org, loongarch@lists.linux.dev, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-um@lists.infradead.org, Qi Zheng References: From: "David Hildenbrand (Red Hat)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Stat-Signature: erytsh3mixedgk7r5re76px3zawqrckj X-Rspamd-Queue-Id: 121BA40008 X-Rspam-User: X-Rspamd-Server: rspam02 X-HE-Tag: 1768818051-681070 X-HE-Meta: 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 WLfo4sX0 nSqPyHJ7urwEksOU/XVoAyB0dupn/tesVrf8pcABON6/war1GhTiOX9tU/8IiwDsIjbXCyRJCP/tS6XltBu9NhzTsw2Gz9ov35eKRmhNggs7xrOM5vYH7XR8ezC/qRcEqOR94yYwIs9Od9s7kK6vg7Q6/hCvOgnbeObE5mEB69JohBWwtojvT9mdYdirvBDEtqDX84/ZTDg6zAt+ZJlc+8RIahiGzkxTs+qrsfmMDRH2LBWvsZi76F7BAwVdp21KNUWHQVYqlCWa9aPxHsu08c86m9pPbw3Avd48bF+/iNyZwoFmZ4ND0t1NcekukKx3/h72/+eUw8zC+KsxJ2I4TwKROrCVsmRFPyRQ6 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: List-Subscribe: List-Unsubscribe: On 12/17/25 10:45, Qi Zheng wrote: > From: Qi Zheng > > The PT_RECLAIM can work on all architectures that support > MMU_GATHER_RCU_TABLE_FREE, so make PT_RECLAIM depends on > MMU_GATHER_RCU_TABLE_FREE. > > BTW, change PT_RECLAIM to be enabled by default, since nobody should want > to turn it off. Right, and if there is ever a need to, I wonder whether that should be a boottime/runtime toggle instead. So far we haven't heard of any relevant runtime overheads that causes problems. > > Signed-off-by: Qi Zheng > --- > arch/x86/Kconfig | 1 - > mm/Kconfig | 9 ++------- > 2 files changed, 2 insertions(+), 8 deletions(-) > > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig > index 80527299f859a..0d22da56a71b0 100644 > --- a/arch/x86/Kconfig > +++ b/arch/x86/Kconfig > @@ -331,7 +331,6 @@ config X86 > select FUNCTION_ALIGNMENT_4B > imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI > select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE > - select ARCH_SUPPORTS_PT_RECLAIM if X86_64 > select ARCH_SUPPORTS_SCHED_SMT if SMP > select SCHED_SMT if SMP > select ARCH_SUPPORTS_SCHED_CLUSTER if SMP > diff --git a/mm/Kconfig b/mm/Kconfig > index bd0ea5454af82..fc00b429b7129 100644 > --- a/mm/Kconfig > +++ b/mm/Kconfig > @@ -1447,14 +1447,9 @@ config ARCH_HAS_USER_SHADOW_STACK > The architecture has hardware support for userspace shadow call > stacks (eg, x86 CET, arm64 GCS or RISC-V Zicfiss). > > -config ARCH_SUPPORTS_PT_RECLAIM > - def_bool n > - > config PT_RECLAIM > - bool "reclaim empty user page table pages" > - default y > - depends on ARCH_SUPPORTS_PT_RECLAIM && MMU && SMP > - select MMU_GATHER_RCU_TABLE_FREE > + def_bool y > + depends on MMU_GATHER_RCU_TABLE_FREE > help > Try to reclaim empty user page table pages in paths other than munmap > and exit_mmap path. Nothing jumped at me. Hopefully we're not missing something important :) Acked-by: David Hildenbrand (Red Hat) -- Cheers David