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Thu, 12 Feb 2026 15:33:13 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id 8Z7fGbnyjWm/PgAAD6G6ig (envelope-from ); Thu, 12 Feb 2026 15:33:13 +0000 Date: Thu, 12 Feb 2026 15:33:11 +0000 From: Pedro Falcato To: Nico Pache Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, aarcange@redhat.com, akpm@linux-foundation.org, anshuman.khandual@arm.com, apopple@nvidia.com, baohua@kernel.org, baolin.wang@linux.alibaba.com, byungchul@sk.com, catalin.marinas@arm.com, cl@gentwo.org, corbet@lwn.net, dave.hansen@linux.intel.com, david@kernel.org, dev.jain@arm.com, gourry@gourry.net, hannes@cmpxchg.org, hughd@google.com, jackmanb@google.com, jack@suse.cz, jannh@google.com, jglisse@google.com, joshua.hahnjy@gmail.com, kas@kernel.org, lance.yang@linux.dev, Liam.Howlett@oracle.com, lorenzo.stoakes@oracle.com, mathieu.desnoyers@efficios.com, matthew.brost@intel.com, mhiramat@kernel.org, mhocko@suse.com, peterx@redhat.com, rakie.kim@sk.com, raquini@redhat.com, rdunlap@infradead.org, richard.weiyang@gmail.com, rientjes@google.com, rostedt@goodmis.org, rppt@kernel.org, ryan.roberts@arm.com, shivankg@amd.com, sunnanyong@huawei.com, surenb@google.com, thomas.hellstrom@linux.intel.com, tiwai@suse.de, usamaarif642@gmail.com, vbabka@suse.cz, vishal.moola@gmail.com, wangkefeng.wang@huawei.com, will@kernel.org, willy@infradead.org, yang@os.amperecomputing.com, ying.huang@linux.alibaba.com, ziy@nvidia.com, zokeefe@google.com Subject: Re: [PATCH mm-unstable v1 5/5] mm/khugepaged: unify khugepaged and madv_collapse with collapse_single_pmd() Message-ID: References: <20260212021835.17755-1-npache@redhat.com> <20260212022512.19076-1-npache@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260212022512.19076-1-npache@redhat.com> X-Rspamd-Action: no action X-Rspam-User: X-Rspamd-Queue-Id: 7C6E510000C X-Rspamd-Server: rspam07 X-Stat-Signature: 4a7zxqsmb7zucgyyhyq3d9pufmhm9zra X-HE-Tag: 1770910398-101380 X-HE-Meta: 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 O0osPVyo 0G3nXg6svqZNo79nYVZw4o6pfcPgXcaLxNz7z6Y8Nn0dwoSU5wMUWY6+U9PdUmRxxvZKlCEnjYCMrHuxPbJ5wapeDbforvdaZbUngODIwD7xTlHMCXvNzLsbcEIgWwultSNUPFcbuL/5kBtxsyx6MF4wqrA0gWNs8VNnQjCXmFu8xC+v9F9TXMsc6mMRgVad85YeaIrAxuoB7dul9Cyi1oa/awTye1yHy0TtVUISkoHC+E9r/R42Lu/j1kUDl9NPUsDDXdFlT/e1WYcRHtoPtDyR97r3aH0hfcahn1rU/hFpVsyVr2TNXiPHRYfzhZiTWxLCs+Brnnd96/BBAh0gbPeKcj9nKDDgnUi7LmNhuO5WWRyFE4LuIVG4pU66IK1kZNghGdpV5lPw3LNNpWa2GVpTwjG3QTwSMIJ4Gh+3PCHvDcbG5ryNeyW8ccG/2xOwwqWr+hoxoT8pcCj1kWCsgtMyu2Q== 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 Wed, Feb 11, 2026 at 07:25:12PM -0700, Nico Pache wrote: > The khugepaged daemon and madvise_collapse have two different > implementations that do almost the same thing. > > Create collapse_single_pmd to increase code reuse and create an entry > point to these two users. > > Refactor madvise_collapse and collapse_scan_mm_slot to use the new > collapse_single_pmd function. This introduces a minor behavioral change > that is most likely an undiscovered bug. The current implementation of > khugepaged tests collapse_test_exit_or_disable before calling > collapse_pte_mapped_thp, but we weren't doing it in the madvise_collapse > case. By unifying these two callers madvise_collapse now also performs > this check. We also modify the return value to be SCAN_ANY_PROCESS which > properly indicates that this process is no longer valid to operate on. > > We also guard the khugepaged_pages_collapsed variable to ensure its only > incremented for khugepaged. > > Reviewed-by: Lorenzo Stoakes > Signed-off-by: Nico Pache Acked-by: Pedro Falcato -- Pedro