On Sun, Feb 16, 2025 at 06:05:14PM +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 I want to add the 'echo 0 > /proc/sys/vm/drop_caches'
> way to enabled the message again.
>
> Signed-off-by: Ruiwu Chen <rwchen404@xxxxxxxxx>
> ---
> fs/drop_caches.c | 7 +++++--
> kernel/sysctl.c | 2 +-
> 2 files changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/fs/drop_caches.c b/fs/drop_caches.c
> index d45ef541d848..c90cfaf9756d 100644
> --- a/fs/drop_caches.c
> +++ b/fs/drop_caches.c
> @@ -57,7 +57,7 @@ int drop_caches_sysctl_handler(const struct ctl_table *table, int write,
> if (ret)
> return ret;
> if (write) {
> - static int stfu;
> + static bool stfu;
>
> if (sysctl_drop_caches & 1) {
> lru_add_drain_all();
> @@ -73,7 +73,10 @@ int drop_caches_sysctl_handler(const struct ctl_table *table, int write,
> current->comm, task_pid_nr(current),
> sysctl_drop_caches);
> }
> - stfu |= sysctl_drop_caches & 4;
> + if (sysctl_drop_caches == 0)
> + stfu = false;
> + else if (sysctl_drop_caches == 4)
> + stfu = true;
> }
> return 0;
> }
> diff --git a/kernel/sysctl.c b/kernel/sysctl.c
> index cb57da499ebb..f2e06e074724 100644
> --- a/kernel/sysctl.c
> +++ b/kernel/sysctl.c
> @@ -2088,7 +2088,7 @@ static const struct ctl_table vm_table[] = {
> .maxlen = sizeof(int),
> .mode = 0200,
> .proc_handler = drop_caches_sysctl_handler,
> - .extra1 = SYSCTL_ONE,
> + .extra1 = SYSCTL_ZERO,
> .extra2 = SYSCTL_FOUR,
> },
> {
> --
> 2.27.0
>
All this has changed with Kaixiong's move of the vm_table.
Please rebase this on top of sysctl-next [1] and send a V2
Best
[1] https://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl.git/log/?h=sysctl-next
--
Joel Granados
