Re: [PATCH] ipc: optimize semget/shmget/msgget for lots of keys

From	Davidlohr Bueso <dave@stgolabs.net>
Newsgroups	linux.kernel
Subject	Re: [PATCH] ipc: optimize semget/shmget/msgget for lots of keys
Date	2017-08-02 22:10 +0200
Message-ID	<ua87U-6eM-9@gated-at.bofh.it> (permalink)
References	<u9eyL-40A-31@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Mon, 31 Jul 2017, Guillaume Knispel wrote:
> static int __init ipc_init(void)
> {
>-	sem_init();
>-	msg_init();
>+	int err_sem, err_msg;
>+
>+	err_sem = sem_init();
>+	WARN(err_sem, "ipc: sysV sem_init failed: %d\n", err_sem);
>+	err_msg = msg_init();
>+	WARN(err_msg, "ipc: sysV msg_init failed: %d\n", err_msg);
> 	shm_init();

This shows the ugliness of the underlying ipc init asymmetry. Specifically,
140d0b2108f (Do 'shm_init_ns()' in an early pure_initcall) was the final
nail in the coffin to fix an exit_shm() race.

While normally we could just initialize the ipc_ids fields statically and
be over with initcall dependencies, your patch will require inits be done
dynamically for the rhashtable_init(). Oh well.

Also, why do you do this?

> -pure_initcall(ipc_ns_init);
> +core_initcall(ipc_ns_init);

Thanks,
Davidlohr

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Re: [PATCH] ipc: optimize semget/shmget/msgget for lots of keys Davidlohr Bueso <dave@stgolabs.net> - 2017-08-02 22:10 +0200
  Re: [PATCH] ipc: optimize semget/shmget/msgget for lots of keys Guillaume Knispel <guillaume.knispel@supersonicimagine.com> - 2017-08-03 19:20 +0200
    Re: [PATCH] ipc: optimize semget/shmget/msgget for lots of keys Davidlohr Bueso <dave@stgolabs.net> - 2017-08-07 19:40 +0200

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