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[109.81.87.166]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-482b1450fb9sm4258529f8f.14.2026.08.19.01.50.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 19 Aug 2026 01:50:14 -0700 (PDT) Date: Wed, 19 Aug 2026 10:50:13 +0200 From: Michal Hocko To: "David Hildenbrand (Arm)" Cc: Andrew Morton , Leon Hwang , linux-mm@kvack.org, Muchun Song , Oscar Salvador , linux-kernel@vger.kernel.org, Lance Yang Subject: Re: [PATCH] hugetlb: add cond_resched() to __unmap_hugepage_range() Message-ID: References: <20260818135029.93288-1-leon.hwang@linux.dev> <3dadebb3-7e2a-459c-a5e8-b375faf89938@kernel.org> <20260818111756.6b0e347db3170bc22cc3c5af@linux-foundation.org> <2a523945-825c-45a5-a680-37e941e092d3@kernel.org> <20260818115526.654d7311366b66cd031c67e4@linux-foundation.org> <35cca76a-4d3a-451a-b492-dd4423ac3e63@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <35cca76a-4d3a-451a-b492-dd4423ac3e63@kernel.org> On Wed 19-08-26 09:53:25, David Hildenbrand wrote: > On 8/18/26 20:55, Andrew Morton wrote: > > On Tue, 18 Aug 2026 20:21:37 +0200 "David Hildenbrand (Arm)" wrote: > > > >>> > >>> That's pretty bad behavior and we might want to fix it in earlier > >>> kernels. Is PREEMPT_NONE effectively dead in 6.18.x and its > >>> existing users? > >>> > >>> If yes, we do want to fix older kernels then we should merge this. > >>> > >> > >> Okay, but that would be stable-only fixes? > > > > Not understanding. > > > > Maybe you refer to adding a patch to -stable but not to -linus? That's > > against the -stable rules > > (Documentation/process/stable-kernel-rules.rst). > > It's tricky: if a problem only exists in stable (there is nothing to fix in > Linus' tree), then a stable-only fix is acceptable. The crucial quiestion is whether this is something that needs a code fix or a configuration fix. Really fighting for low latencies with PREEMPT_NONE is a kinda lost battle. You might want to play whack a mole... -- Michal Hocko SUSE Labs