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Date:   Wed, 9 Mar 2022 19:29:47 -0800
From:   Andrew Morton <akpm@linux-foundation.org>
To:     wangjianxing <wangjianxing@loongson.cn>
Cc:     Matthew Wilcox <willy@infradead.org>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, vbabka@suse.cz
Subject: Re: [PATCH 1/1] mm/page_alloc: add scheduling point to
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Message-Id: <20220309192947.0b4c8c875c492de09c1ab632@linux-foundation.org>
In-Reply-To: <3713cb82-9596-9916-9830-c2827d6a6fe4@loongson.cn>
References: <20220302013825.2290315-1-wangjianxing@loongson.cn>
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On Thu, 10 Mar 2022 10:48:41 +0800 wangjianxing <wangjianxing@loongson.cn> =
wrote:

> spin_lock will preempt_disable(), interrupt context will=20
> __irq_enter/local_bh_disable and also add preempt count with offset.
>=20
> cond_resched check whether if preempt_count =3D=3D 0 in first and won't=20
> schedule in previous context.
>=20
> Is this right?
>=20
>=20
> With another way, could we add some condition to avoid call cond_resched=
=20
> in interrupt context or spin_lock()?
>=20
> + if (preemptible())
> +=A0=A0 =A0=A0=A0 cond_resched();
>=20

None of this works with CONFIG_PREEMPTION=3Dn.