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Date:   Mon, 26 Jul 2021 10:20:35 +0200
From:   Michal Hocko <mhocko@suse.com>
To:     Shakeel Butt <shakeelb@google.com>
Cc:     Suren Baghdasaryan <surenb@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        David Rientjes <rientjes@google.com>,
        Matthew Wilcox <willy@infradead.org>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Roman Gushchin <guro@fb.com>, Rik van Riel <riel@surriel.com>,
        Minchan Kim <minchan@kernel.org>,
        Christian Brauner <christian@brauner.io>,
        Christoph Hellwig <hch@infradead.org>,
        Oleg Nesterov <oleg@redhat.com>,
        David Hildenbrand <david@redhat.com>,
        Jann Horn <jannh@google.com>,
        Andy Lutomirski <luto@kernel.org>,
        Christian Brauner <christian.brauner@ubuntu.com>,
        Florian Weimer <fweimer@redhat.com>, jengelh@inai.de,
        Tim Murray <timmurray@google.com>,
        Linux API <linux-api@vger.kernel.org>,
        Linux MM <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>,
        kernel-team <kernel-team@android.com>
Subject: Re: [PATCH v3 1/2] mm: introduce process_mrelease system call
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References: <20210723011436.60960-1-surenb@google.com>
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On Thu 22-07-21 19:03:56, Shakeel Butt wrote:
> On Thu, Jul 22, 2021 at 6:14 PM Suren Baghdasaryan <surenb@google.com> wrote:
> >
> [...]
> > +
> > +       mmap_read_lock(mm);
> 
> How about mmap_read_trylock(mm) and return -EAGAIN on failure?

Btw. wether there is a non-blocking variant or not we should use
killable waiting to make sure the task calling into this is killable
by userspace (e.g. to implement a timeout based approach).
-- 
Michal Hocko
SUSE Labs