On Mon, Mar 10, 2025 at 02:51:11PM +0100, Joel Granados wrote: > On Sat, Mar 08, 2025 at 04:05:49PM +0800, Ruiwu Chen wrote: > > >> When 'echo 4 > /proc/sys/vm/drop_caches' the message is disabled, > > >> but there is no interface to enable the message, only by restarting > > >> the way, so add the 'echo 0 > /proc/sys/vm/drop_caches' way to > > >> enabled the message again. > > >> > > >> Signed-off-by: Ruiwu Chen <rwchen404@xxxxxxxxx> > > > > > > You are overcomplicating things, if you just want to re-enable messages > > > you can just use: > > > > > > - stfu |= sysctl_drop_caches & 4; > > > + stfu = sysctl_drop_caches & 4; > > > > > > The bool is there as 4 is intended as a bit flag, you can can figure > > > out what values you want and just append 4 to it to get the expected > > > result. > > > > > > Luis > > > > Is that what you mean ? > > > > - stfu |= sysctl_drop_caches & 4; > > + stfu ^= sysctl_drop_caches & 4; > > > > 'echo 4 > /sys/kernel/vm/drop_caches' can disable or open messages, > > This is what I originally thought, but there is uncertainty that when different operators execute the command, > > It is not possible to determine whether this time is enabled or turned on unless you operate it twice. > > So can you use ^= or not? No, ^= does not work, see a boolean truth table. > And what does operate it twice mean? I think the reporter meant an "sysadmin", say two folks admining a system. Since we this as a flag to enable disabling it easily we can just always check for the flag as I suggested: stfu = sysctl_drop_caches & 4 Luis
