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Subject: Re: [PATCH 2/3] mm: Extract might_alloc() debug check
To:     Daniel Vetter <daniel.vetter@ffwll.ch>,
        DRI Development <dri-devel@lists.freedesktop.org>
Cc:     Intel Graphics Development <intel-gfx@lists.freedesktop.org>,
        linux-mm@kvack.org, linux-xfs@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
        Vlastimil Babka <vbabka@suse.cz>,
        "Paul E . McKenney" <paulmck@kernel.org>,
        Christoph Lameter <cl@linux.com>,
        Pekka Enberg <penberg@kernel.org>,
        David Rientjes <rientjes@google.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@kernel.org>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
        Michel Lespinasse <walken@google.com>,
        Waiman Long <longman@redhat.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Dave Chinner <david@fromorbit.com>, Qian Cai <cai@lca.pw>,
        "Matthew Wilcox (Oracle)" <willy@infradead.org>,
        Daniel Vetter <daniel.vetter@intel.com>
References: <20201120095445.1195585-1-daniel.vetter@ffwll.ch>
 <20201120095445.1195585-3-daniel.vetter@ffwll.ch>
From:   Randy Dunlap <rdunlap@infradead.org>
Message-ID: <bfe3b1a4-9cc0-358f-a62e-b6d9a68e735a@infradead.org>
Date:   Fri, 20 Nov 2020 09:19:56 -0800
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Hi,

On 11/20/20 1:54 AM, Daniel Vetter wrote:
> diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h
> index d5ece7a9a403..f94405d43fd1 100644
> --- a/include/linux/sched/mm.h
> +++ b/include/linux/sched/mm.h
> @@ -180,6 +180,22 @@ static inline void fs_reclaim_acquire(gfp_t gfp_mask) { }
>  static inline void fs_reclaim_release(gfp_t gfp_mask) { }
>  #endif
>  
> +/**
> + * might_alloc - Marks possible allocation sites

                    Mark

> + * @gfp_mask: gfp_t flags that would be use to allocate

                                           used

> + *
> + * Similar to might_sleep() and other annotations this can be used in functions

                                         annotations,

> + * that might allocate, but often dont. Compiles to nothing without

                                     don't.

> + * CONFIG_LOCKDEP. Includes a conditional might_sleep() if @gfp allows blocking.

?                                            might_sleep_if() if

> + */
> +static inline void might_alloc(gfp_t gfp_mask)
> +{
> +	fs_reclaim_acquire(gfp_mask);
> +	fs_reclaim_release(gfp_mask);
> +
> +	might_sleep_if(gfpflags_allow_blocking(gfp_mask));
> +}


-- 
~Randy