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charset=us-ascii Content-Disposition: inline In-Reply-To: <20250211082138.iqvedSfG@linutronix.de> X-Rspam-User: X-Rspamd-Queue-Id: A743DA000E X-Rspamd-Server: rspam07 X-Stat-Signature: rko5d9ue9xx1jzk8xecww8kth4h7zkmb X-HE-Tag: 1739271449-13337 X-HE-Meta: U2FsdGVkX197c8DaXezN173jACFSR+buRLY2Lhfi1pFjRoTrO141oTaIp5aEBPe4vnsgK3huKs+Eb2KKdu3apmzmqWXaTkrZ4edxpDeHba2vsiPn/46i9edCkRky0/AlTKg5wE1SFSVOOroHQ32Ipk2nlU1ZsdbbqurYqo30T2UTHJuK8Djc9a8odf+otc/yFda++CmEKf17C897lw6EO68bkc6sdIUCKiFtZvpKTD3Y+UhPDzs5xHgiQ/97uoMWhCOqUPF6s0oWhyRQbbXjYJf0XSSa6X1Yax7R4x+Rf+gjmilyq7Vm2NDSIqAdL1E50QuFOamsWCw95DcTLaw3/ecKRQ37DDpB/WqkDh+OOUpgo03wx9LddqKHtkL+OlWcY/6vsRU3RRuXSnkaX8zRhD4LhKUwgPwGhUEUSPjgiB17TQOhB72pm3ibVk5mRLZxfyQYcI1eTSCEIzJC8GtiHdHWbf1KVM6Ii5FehvPsBi/oc++1Nz1J/oqWpuGMWFZsTufN3OB3c7oQ9G46BEki3Jy7aK0IjrwuiTgpD8q9G3vI7yLIQYgGuxoEBw6nIhNW169R4S5YakIl8kYi6hZGGJm8XGi9Aj7ebi7g31OdfjQqbCQwBglKVs7N3ToykOzWjBR6WsCmYH4HyMS5Hz8mNIjWihPIH/A4bvlTdIIvn5kfY3p4I9LwKf3AK6NjQvOC/H3ceKQtmMPrT/8Y4Rvjh8WrsTEriLkwKPxO3lH5fi4ryTXlG4fYmSl/MwBeeExHG0XxDN4dTHLfRnPzkWrrqZ4KnA4xkTDZO6Nk4HJpQlQQdaws7ZSYL9AqjRJ9JpCL4VdPu0RQdacR/Ox9gDn7gMJcpWy+V+1GYeMzSjUjKc6GcTvoWeFs+0NnNx27sV72czSETDtx4AW8vr0hEdzhyBM79nQbfRCbl8odI0Wc3cX40GVVDfNtVfmZ21cy+qOfeJ0enQRQeL/Kt3thHXk 7aULD84H Us039I7f45FRKX8ldCN5kBWxpvr8daLResDqL9FHOOOwJ+zKju7yMKTJLSx2sBtUIEuqcImmL27ytxd1WhxuD1dAaD56nTJnSvL5nFF6BLz3j+3ZgIjjK9YQqoTcmkOQbf3EhjvmMYNhMmBtgtIECPJOUkIy8dS9eKAntVjftPoKHKb6nIU2m8HxVMMQ80AV4JBp0w+SGVyki8jXR6VJ7anxFeQ2oYLczZAZDM5QK6S6GvARkyjxSIqfz3IXrSc1fUmsc0bet6NC4F3E= 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 Tue, Feb 11, 2025 at 09:21:38AM +0100, Sebastian Andrzej Siewior wrote: > So with LAZY_PREEMPT (not that one that was merged upstream, its > predecessor) we had a counter similar to the preemption counter. On each > rt_spin_lock() the counter was incremented, on each rt_spin_unlock() the > counter was decremented. Once the counter hit zero and the lazy preempt > flag was set (which was only set on schedule requests by SCHED_OTHER > tasks), we scheduled. > This improved the performance as we didn't schedule() while holding a > spinlock_t and then bump into the same lock in the next task. > > We don't follow this behaviour exactly today. I think I send some hackery Mike's way to implement that at some point. IIRC it wasn't an obvious win. Anyway its not too hard to do.