Hi, Ridong, On Sat, 22 Nov 2025 09:19:39, Chen Ridong wrote: >On 2025/11/21 18:33, Sun Shaojie wrote: >> Is this truly a key requirement? It appears this requirement wasn't met even >> before applying my patch. >> > >I believe it requires, it may some corner cases we should fix. > >> The example below, which does not use this patch, demonstrates how different >> sequences with identical configurations can still lead to different system >> states. >> >> #1> mkdir -p A1 >> #2> mkdir -p B1 | A1's prstate | B1's prstate | >> #3> echo "0-1" > A1/cpuset.cpus | member | member | >> #4> echo "0-1" > A1/cpuset.cpus.exclusive | member | member | >> #5> echo "root" > A1/cpuset.cpus.partition | root | member | >> #6> echo "1-2" > B1/cpuset.cpus | root invalid | member | >> #7> echo "2-3" > B1/cpuset.cpus.exclusive | root invalid | member | >> #8> echo "root" > B1/cpuset.cpus.partition | root invalid | root | >> > >IIUC, you've created this example with the expectation that both A1 and B1 >should serve as root >partitions. However, we currently lack a mechanism where modifying a cpuset's >state (e.g., cpus, >cpus.exclusive, or cpus.partition) can transition its sibling from an invalid >to a valid partition. > >The behavior observed before step #6 is acceptable. Proactively setting B1 as >a partition in step #8 >is permitted, given that B1 does not conflict with A1. However, we do not have >a mechanism to >passively and automatically transition A1 to a valid partition state. >
So, was the original behavior of invalidating sibling partitions driven by this key requirement? (As a key requirement: Regardless of the order in which we apply the configurations, identical final settings should always result in identical system states.) >> #1> mkdir -p A1 >> #2> mkdir -p B1 | A1's prstate | B1's prstate | >> #3> echo "0-1" > A1/cpuset.cpus | member | member | >> #4> echo "0-1" > A1/cpuset.cpus.exclusive | member | member | >> #5> echo "2-3" > B1/cpuset.cpus.exclusive | member | member | >> #6> echo "root" > A1/cpuset.cpus.partition | root | member | >> #7> echo "1-2" > B1/cpuset.cpus | root | member | >> #8> echo "root" > B1/cpuset.cpus.partition | root | root | >> >> Even without this patch, the result can still differ. >> Thanks, Sun Shaojie
