From: Florian Weimer <fweimer@redhat.com>
To: Cupertino Miranda via Libc-alpha <libc-alpha@sourceware.org>
Cc: Cupertino Miranda <cupertino.miranda@oracle.com>,
jose.marchesi@oracle.com, elena.zannoni@oracle.com,
adhemerval.zanella@linaro.org
Subject: Re: [PATCH] Created tunable to force small pages on stack allocation.
Date: Mon, 13 Mar 2023 08:54:46 +0100 [thread overview]
Message-ID: <87edptulvd.fsf@oldenburg.str.redhat.com> (raw)
In-Reply-To: <20230310143558.361825-2-cupertino.miranda@oracle.com> (Cupertino Miranda via Libc-alpha's message of "Fri, 10 Mar 2023 14:35:58 +0000")
* Cupertino Miranda via Libc-alpha:
> +static void
> +TUNABLE_CALLBACK (set_stack_hugetlb) (tunable_val_t *valp)
> +{
> + enum malloc_thp_mode_t thp_mode = __malloc_thp_mode ();
> + /*
> + Only allow to change the default of this tunable if the system
> + does support and has either 'madvise' or 'always' mode. Otherwise
> + the madvise() call is wasteful.
> + */
> + switch(thp_mode)
> + {
> + case malloc_thp_mode_always:
> + case malloc_thp_mode_madvise:
> + __nptl_stack_hugetlb = (int32_t) valp->numval;
> + break;
> + default:
> + break;
> + }
> +}
I suspect that quite a few failing madvise calls are cheaper than the
those three system calls in __malloc_thp_mode. In addition,
__malloc_thp_mode may fail due to future kernel changes, disabling the
tunable by accident.
Thanks,
Florian
next prev parent reply other threads:[~2023-03-13 7:54 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-10 14:35 Cupertino Miranda
2023-03-10 14:35 ` Cupertino Miranda
2023-03-13 7:54 ` Florian Weimer [this message]
2023-03-13 10:07 ` Cupertino Miranda
2023-03-13 17:10 ` Cupertino Miranda
2023-03-13 17:18 ` Cupertino Miranda
2023-03-13 17:15 ` Adhemerval Zanella Netto
2023-03-13 17:32 ` Cupertino Miranda
2023-03-13 17:17 ` Cupertino Miranda
2023-03-20 15:41 [v2] Created tunable to force small pages on stack Cupertino Miranda
2023-03-20 15:41 ` [PATCH] Created tunable to force small pages on stack allocation Cupertino Miranda
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