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Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Zach O'Keefe , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Branden Moore References: <20251201185604.210634-6-shivankg@amd.com> <20251201185604.210634-8-shivankg@amd.com> From: Baolin Wang In-Reply-To: <20251201185604.210634-8-shivankg@amd.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: B4CE440009 X-Stat-Signature: 6eouctdhfbhf61b1c4hd8w6cx6gocm5o X-Rspam-User: X-HE-Tag: 1764662206-27843 X-HE-Meta: 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 wF09weEA 3IEip81p2pKwV7WBA58lWd9fCGsWhnLNg+2axe/kJqZdS6Oc9z1Qvz/wxJl/f+vNlrw9KQnDlfShUYRRuFBFF1BG7K/be5CRcUKcKl+FCqOth9uRIDvFCSIXnMvYyolfgWGxc7sMCKieILFaRg6lbRhWx1EfxrBhVhjXXwz0MWurPlRIXP8SY4AVyI/7ihAbJeHbglBMAfjHps1OrKtkvc5ROMzni+uw4jj+qrxVS8UeX5pN71QwZfTPpjZycPAEvJCqKVV7eFZ4WY45Z3HmaETttmek3BYfHBX49JPCST04Tu/5S8qEjk1be4dg76xMrQa2iRRo8eib+uYAWVDNqCKZY2ib8A9L3p/kpFKBUheIJCQ0+WPdB7ptdqwt06pi2nJoyMiULXajas75Vt5P/43cXww== 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 2025/12/2 02:56, Shivank Garg wrote: > When collapse_file encounters dirty or writeback pages in file-backed > mappings, it currently returns SCAN_FAIL which maps to -EINVAL. This is > misleading as EINVAL suggests invalid arguments, whereas dirty/writeback > pages represent transient conditions that may resolve on retry. > > Introduce SCAN_PAGE_DIRTY_OR_WRITEBACK to cover both dirty and writeback > states, mapping it to -EAGAIN. For MADV_COLLAPSE, this provides userspace > with a clear signal that retry may succeed after writeback completes. > For khugepaged, this is harmless as it will naturally revisit the range > during periodic scans after async writeback completes. > > Reported-by: Branden Moore > Closes: https://lore.kernel.org/all/4e26fe5e-7374-467c-a333-9dd48f85d7cc@amd.com > Fixes: 34488399fa08 ("mm/madvise: add file and shmem support to MADV_COLLAPSE") > Reviewed-by: Dev Jain > Reviewed-by: Lance Yang > Signed-off-by: Shivank Garg > --- LGTM. Reviewed-by: Baolin Wang