linux-kernel - Re: mlock() confusing 1 half of system RAM limit

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Message-ID: <20180601134154.GD15278@dhcp22.suse.cz>
Date:   Fri, 1 Jun 2018 15:41:54 +0200
From:   Michal Hocko <mhocko@...nel.org>
To:     Alex Richman <alex.r@...abs.co.uk>
Cc:     linux-man@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: mlock() confusing 1 half of system RAM limit

On Fri 01-06-18 14:24:23, Alex Richman wrote:
> Ah, that's it.  Increased the limit on the mount and it works fine now.

Well, it is hidden very well. It is not until the page fault time (or
get_user_pages aka __mm_populate) when the operation fails and remasks
ENOSPC -> VM_FAULT_SIGBUS -> EFAULT -> ENOMEM on the way.
-- 
Michal Hocko
SUSE Labs