Messages in this thread | | | Date | Thu, 21 Jan 2021 13:39:13 -0800 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH RFC cpumask] Allow "all", "none", and "last" in cpumask strings |
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On Thu, Jan 21, 2021 at 08:57:25AM -0800, Paul E. McKenney wrote: > On Wed, Jan 20, 2021 at 11:11:48PM -0800, Yury Norov wrote: > > On Wed, Jan 6, 2021 at 12:49 AM Yury Norov <yury.norov@gmail.com> wrote: > > > > > > On Tue, Jan 5, 2021 at 4:48 PM Paul E. McKenney <paulmck@kernel.org> wrote: > > > > > > > > Hello! > > > > > > > > This series allows "all", "none", and "last" to be used in cpumask > > > > strings. This allows these strings to be less dependent on the underlying > > > > system. For example, currently a string specifying all but the first > > > > CPU must be "1-7" on an eight-CPU system and "1-15" on a 16-CPU system. > > > > With this series, the single string "1-last" can be used regardless of the > > > > number of CPUs (at least assuming that each system has at least one CPU). > > > > > > 'none' may be implemented as an empty string or string with separators only, > > > but I have nothing against explicit 'none'. See other comments inline. > > > > > > Thanks, > > > Yury. > > > > > > > 1. Un-inline cpulist_parse for SMP; prepare for ascii helpers, > > > > courtesy of Paul Gortmaker. > > > > > > > > 2. Make "all" alias global and not just RCU, courtesy of Paul > > > > Gortmaker. > > > > > > > > 3. Add a "none" alias to complement "all", courtesy of Paul > > > > Gortmaker. > > > > > > > > 4. Add "last" alias for cpu list specifications, courtesy of Paul > > > > Gortmaker. > > > > > > > > 5. Use "all" and "last" in "nohz_full" and "rcu_nocbs". > > > > > > > > Thanx, Paul > > > > Hi Paul, > > > > Today I found this series in linux-next despite downsides discovered during > > the review. This series introduces absolutely unneeded cap on the number of > > cpus in the system (9999), and also adds unsafe and non-optimal code. > > > > In addition to that, I observe this warning on powerpc: > > CC lib/cpumask.o > > lib/cpumask.c: In function ‘cpulist_parse’: > > lib/cpumask.c:222:17: warning: cast from pointer to integer of > > different size [-Wpointer-to-int-cast] > > 222 | memblock_free((phys_addr_t)cpulist, len); > > | ^ > > > > Can you please revert this series unless all the problems will be fixed? > > Thank you for your further review and comments! > > I had been keeping the old series as a placeholder for its anticipated > replacement, but given the compiler warning you note above and given > that it is getting uncomfortably close to the time when I send my pull > request, I will remove it from the -rcu rcu/next branch sourced by -next.
Except that the resulting rebasing and testing took too long, so there will be one more -next with these commits.
Thanx, Paul
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