| Message ID | 20230325071420.2246461-3-liushixin2@huawei.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Delay the initialization of zswap | expand |
On (23/03/25 15:14), Liu Shixin wrote: > +++ b/mm/zswap.c > @@ -761,15 +761,15 @@ static int __zswap_param_set(const char *val, const struct kernel_param *kp, > char *s = strstrip((char *)val); > int ret; > > + /* no change required */ > + if (!strcmp(s, *(char **)kp->arg) && zswap_has_pool) > + return 0; > + > if (zswap_init_failed) { > pr_err("can't set param, initialization failed\n"); > return -ENODEV; > } > > - /* no change required */ > - if (!strcmp(s, *(char **)kp->arg) && zswap_has_pool) > - return 0; I probably would suggest to simply remove `*(char **)kp->arg` from zswap code entirely, it doesn't solve any real problem (as far as I can tell).
On (23/03/25 15:14), Liu Shixin wrote: > static int zswap_enabled_param_set(const char *val, > const struct kernel_param *kp) > { > + bool res; > + > + if (kstrtobool(val, &res)) > + return -EINVAL; > + > + /* no change required */ > + if (res == *(bool *)kp->arg) > + return 0; Bool kernel param can be any of these letters 'YyTt1NnFf0'. Doing things to kp->arg outside of kernel/params.c is not going to be easy, let's not even try.
On (23/03/26 12:17), Sergey Senozhatsky wrote: > On (23/03/25 15:14), Liu Shixin wrote: > > static int zswap_enabled_param_set(const char *val, > > const struct kernel_param *kp) > > { > > + bool res; > > + > > + if (kstrtobool(val, &res)) > > + return -EINVAL; > > + > > + /* no change required */ > > + if (res == *(bool *)kp->arg) > > + return 0; > > Bool kernel param can be any of these letters 'YyTt1NnFf0'. Doing things > to kp->arg outside of kernel/params.c is not going to be easy, let's not > even try. Please disregard my previous email. kp->arg is always true or false at this point. I'd still prefer to not do kp->arg in zswap.
On Sun, Mar 26, 2023 at 01:53:27PM +0900, Sergey Senozhatsky wrote: > > > + if (kstrtobool(val, &res)) > > > + return -EINVAL; > > > + > > > + /* no change required */ > > > + if (res == *(bool *)kp->arg) > > > + return 0; > > > > Bool kernel param can be any of these letters 'YyTt1NnFf0'. Doing things > > to kp->arg outside of kernel/params.c is not going to be easy, let's not > > even try. > > Please disregard my previous email. kp->arg is always true or false > at this point. I'd still prefer to not do kp->arg in zswap. The whole parameter handling in zswap is a mess and I don't really have a good idea how to solve it all. But for this "paramter not changed" case I think we can helper a lot by adding a core moduleparam.h helper to encapsule it. I.e.: static inline bool param_bool_unchanged(bool val, const struct kernel_param *kp) return val == *(bool *)kp->arg); } and at least keep it out of zswap.
On 2023/3/27 7:25, Christoph Hellwig wrote: > On Sun, Mar 26, 2023 at 01:53:27PM +0900, Sergey Senozhatsky wrote: >>>> + if (kstrtobool(val, &res)) >>>> + return -EINVAL; >>>> + >>>> + /* no change required */ >>>> + if (res == *(bool *)kp->arg) >>>> + return 0; >>> Bool kernel param can be any of these letters 'YyTt1NnFf0'. Doing things >>> to kp->arg outside of kernel/params.c is not going to be easy, let's not >>> even try. >> Please disregard my previous email. kp->arg is always true or false >> at this point. I'd still prefer to not do kp->arg in zswap. > The whole parameter handling in zswap is a mess and I don't really > have a good idea how to solve it all. > > But for this "paramter not changed" case I think we can helper a lot > by adding a core moduleparam.h helper to encapsule it. I.e.: > > static inline bool param_bool_unchanged(bool val, > const struct kernel_param *kp) > > return val == *(bool *)kp->arg); > } > > and at least keep it out of zswap. Thanks for your advice. I will try this way. > > . >
diff --git a/mm/zswap.c b/mm/zswap.c index 6d2b879f091e..d2adc1ffe47d 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -761,15 +761,15 @@ static int __zswap_param_set(const char *val, const struct kernel_param *kp, char *s = strstrip((char *)val); int ret; + /* no change required */ + if (!strcmp(s, *(char **)kp->arg) && zswap_has_pool) + return 0; + if (zswap_init_failed) { pr_err("can't set param, initialization failed\n"); return -ENODEV; } - /* no change required */ - if (!strcmp(s, *(char **)kp->arg) && zswap_has_pool) - return 0; - /* if this is load-time (pre-init) param setting, * don't create a pool; that's done during init. */ @@ -864,6 +864,15 @@ static int zswap_zpool_param_set(const char *val, static int zswap_enabled_param_set(const char *val, const struct kernel_param *kp) { + bool res; + + if (kstrtobool(val, &res)) + return -EINVAL; + + /* no change required */ + if (res == *(bool *)kp->arg) + return 0; + if (zswap_init_failed) { pr_err("can't enable, initialization failed\n"); return -ENODEV;
If parameter is invalid or no change required, return directly. This can reduces unnecessary printing. Signed-off-by: Liu Shixin <liushixin2@huawei.com> --- mm/zswap.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-)