android_kernel_xiaomi_sm8350/kernel
Ingo Molnar 6cb54819d7 [PATCH] remove sys_set_zone_reclaim()
This removes sys_set_zone_reclaim() for now.  While i'm sure Martin is
trying to solve a real problem, we must not hard-code an incomplete and
insufficient approach into a syscall, because syscalls are pretty much
for eternity.  I am quite strongly convinced that this syscall must not
hit v2.6.13 in its current form.

Firstly, the syscall lacks basic syscall design: e.g. it allows the
global setting of VM policy for unprivileged users. (!) [ Imagine an
Oracle installation and a SAP installation on the same NUMA box fighting
over the 'optimal' setting for this flag. What will they do? Will they
try to set the flag to their own preferred value every second or so? ]

Secondly, it was added based on a single datapoint from Martin:

 http://marc.theaimsgroup.com/?l=linux-mm&m=111763597218177&w=2

where Martin characterizes the numbers the following way:

 ' Run-to-run variability for "make -j" is huge, so these numbers aren't
   terribly useful except to see that with reclaim the benchmark still
   finishes in a reasonable amount of time. '

in other words: the fundamental problem has likely not been solved, only
a tendential move into the right direction has been observed, and a
handful of numbers were picked out of a set of hugely variable results,
without showing the variability data. How much variance is there
run-to-run?

I'd really suggest to first walk the walk and see what's needed to get
stable & predictable kernel compilation numbers on that NUMA box, before
adding random syscalls to tune a particular aspect of the VM ... which
approach might not even matter once the whole picture has been analyzed
and understood!

The third, most important point is that the syscall exposes VM tuning
internals in a completely unstructured way. What sense does it make to
have a _GLOBAL_ per-node setting for 'should we go to another node for
reclaim'? If then it might make sense to do this per-app, via numalib or
so.

The change is minimalistic in that it doesnt remove the syscall and the
underlying infrastructure changes, only the user-visible changes.  We
could perhaps add a CAP_SYS_ADMIN-only sysctl for this hack, a'ka
/proc/sys/vm/swappiness, but even that looks quite counterproductive
when the generic approach is that we are trying to reduce the number of
external factors in the VM balance picture.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-08-01 10:03:56 -07:00
..
irq [PATCH] irqpoll 2005-06-28 21:20:35 -07:00
power [PATCH] Address BUG: using smp_processor_id() in preemptible [00000001] code 2005-07-27 16:25:50 -07:00
acct.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
audit.c AUDIT: Unify auid reporting, put arch before syscall number 2005-05-23 21:35:28 +01:00
auditsc.c AUDIT: Record working directory when syscall arguments are pathnames 2005-05-27 12:17:28 +01:00
capability.c [PATCH] kernel/capability.c: add kerneldoc 2005-07-27 16:26:06 -07:00
compat.c [PATCH] Fix get_compat_sigevent() 2005-04-16 15:24:01 -07:00
configs.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
cpu.c [PATCH] i386 CPU hotplug 2005-06-25 16:24:29 -07:00
cpuset.c [PATCH] kernel/cpuset.c: add kerneldoc, fix typos 2005-07-27 16:26:06 -07:00
crash_dump.c [PATCH] kernel/crash_dump.c: add kerneldoc 2005-07-27 16:26:06 -07:00
dma.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
exec_domain.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
exit.c [PATCH] Update cfq io scheduler to time sliced design 2005-06-27 14:33:29 -07:00
extable.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
fork.c [PATCH] lower VM_DONTCOPY total_vm 2005-07-12 16:00:58 -07:00
futex.c [PATCH] convert that currently tests _NSIG directly to use valid_signal() 2005-05-01 08:59:14 -07:00
intermodule.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
itimer.c [PATCH] itimer fixes 2005-07-27 16:25:51 -07:00
kallsyms.c [PATCH] ppc32: platform-specific functions missing from kallsyms. 2005-05-05 16:36:31 -07:00
Kconfig.hz [PATCH] i386: Selectable Frequency of the Timer Interrupt 2005-06-23 09:45:10 -07:00
Kconfig.preempt [PATCH] sched: voluntary kernel preemption 2005-06-25 16:24:45 -07:00
kexec.c [PATCH] kexec: fix sparse warnings 2005-06-28 14:53:40 -07:00
kfifo.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
kmod.c [PATCH] Keys: Pass session keyring to call_usermodehelper() 2005-06-24 00:05:18 -07:00
kprobes.c [PATCH] kprobes: fix namespace problem and sparc64 build 2005-07-05 19:19:00 -07:00
ksysfs.c [PATCH] Kdump: Export crash notes section address through sysfs 2005-06-25 16:24:51 -07:00
kthread.c [PATCH] use smp_mb/wmb/rmb where possible 2005-05-01 08:58:47 -07:00
Makefile [PATCH] kdump: Routines for copying dump pages 2005-06-25 16:24:53 -07:00
module.c [PATCH] make various thing static 2005-06-24 00:06:43 -07:00
panic.c [PATCH] Call emergency_reboot from panic 2005-07-26 14:35:43 -07:00
params.c [PATCH] sysfs: (rest) if show/store is missing return -EIO 2005-06-20 15:15:03 -07:00
pid.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
posix-cpu-timers.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
posix-timers.c [PATCH] posix timers: fix normalization problem 2005-07-28 21:46:05 -07:00
printk.c [PATCH] CPU hotplug printk fix 2005-06-25 16:24:34 -07:00
profile.c [PATCH] mostly_read data section 2005-07-07 18:23:46 -07:00
ptrace.c [PATCH] convert that currently tests _NSIG directly to use valid_signal() 2005-05-01 08:59:14 -07:00
rcupdate.c [PATCH] Deprecate synchronize_kernel, GPL replacement 2005-05-01 08:59:04 -07:00
resource.c [PATCH] Use ALIGN to remove duplicate code 2005-06-25 16:25:02 -07:00
sched.c [PATCH] fix MAX_USER_RT_PRIO and MAX_RT_PRIO 2005-07-26 15:40:00 -07:00
seccomp.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
signal.c [PATCH] Cleanup patch for process freezing 2005-06-25 17:10:13 -07:00
softirq.c [PATCH] revert bogus softirq changes 2005-07-30 10:49:59 -07:00
spinlock.c [PATCH] spin_unlock_bh() and preempt_check_resched() 2005-05-21 10:46:48 -07:00
stop_machine.c [PATCH] smp_processor_id() cleanup 2005-06-21 18:46:13 -07:00
sys_ni.c [PATCH] remove sys_set_zone_reclaim() 2005-08-01 10:03:56 -07:00
sys.c [PATCH] reboot: remove device_suspend(PMSG_FREEZE) from kernel_kexec 2005-07-29 12:02:09 -07:00
sysctl.c [PATCH] s390: spin lock retry 2005-07-27 16:26:04 -07:00
time.c [PATCH] clean up inline static vs static inline 2005-07-27 16:26:20 -07:00
timer.c [PATCH] kernel/timer: fix msleep_interruptible() comment 2005-06-25 16:24:58 -07:00
uid16.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
user.c [PATCH] inotify 2005-07-12 20:38:38 -07:00
wait.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
workqueue.c [PATCH] re-export cancel_rearming_delayed_workqueue 2005-04-16 15:23:59 -07:00