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Peter Anvin" , Shakeel Butt , Suren Baghdasaryan , Thomas Gleixner , Toshi Kani , Vlastimil Babka , Will Deacon , linux-mm@kvack.org, x86@kernel.org Subject: Re: [PATCH 0/3] x86/mm: DEBUG_PAGEALLOC musings Message-ID: <20260804200134.GK776954@noisy.programming.kicks-ass.net> References: <20260729110807.797920433@infradead.org> <2ea2881c-7202-40e7-8fa2-f1c649c0d445@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2ea2881c-7202-40e7-8fa2-f1c649c0d445@intel.com> X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 7701920014 X-Stat-Signature: oxsm368kmgrqg6h94cqfnjx4uxepz7xq X-Rspam-User: X-HE-Tag: 1785873723-658116 X-HE-Meta: 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 h+4IO1V4 hP1SK8XwmjoonGxbCh3e4r+dExC3MiarkasvZ/3RjFkVk59meLQRM8RYzICfLeOlFyPHIATZsmTY7mZGBU0VXzq5AAq+ziW89MluV9eRyMSJgfLorkbVRt1qsNVvvwDitQgF6h4jp9/YBupYcLyOt1Xzx16e8yFK8YEV9MVfbnm6I+szSCwV/ZPoWwaMkumjTalm70qwGJuQ5x7j541m128dO84u/DaAYiJectay6UQRGvRCtWf+sErfRpAKOZFlHQw8YSkRr9cfpycUKF66q+zrBTjIB5t5s+XJU Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Aug 04, 2026 at 11:34:36AM -0700, Dave Hansen wrote: > On 7/29/26 04:08, Peter Zijlstra wrote: > > my take on how we should be 'fixing' this DEBUG_PAGEALLOC thing. It appears to > > boot in qemu with debug_pagealloc=on and such things. > > The approach looks fine to me. The only thing we might want to do is add > a warning of some kind in the split/join paths for CPA_DEBUG_PAGEALLOC. So if you have lockdep enabled hitting them will scream bloody murder on cpa_lock and pgd_lock. But if you want I can sprinkle more explicit warns :-)