From: Steven Rostedt <rostedt@goodmis.org>
To: Sebastian Sewior <bigeasy@linutronix.de>
Cc: Michal Hocko <mhocko@suse.com>,
Alexei Starovoitov <alexei.starovoitov@gmail.com>,
Matthew Wilcox <willy@infradead.org>, bpf <bpf@vger.kernel.org>,
Andrii Nakryiko <andrii@kernel.org>,
Kumar Kartikeya Dwivedi <memxor@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
Vlastimil Babka <vbabka@suse.cz>, Hou Tao <houtao1@huawei.com>,
Johannes Weiner <hannes@cmpxchg.org>,
shakeel.butt@linux.dev, Thomas Gleixner <tglx@linutronix.de>,
Tejun Heo <tj@kernel.org>, linux-mm <linux-mm@kvack.org>,
Kernel Team <kernel-team@fb.com>
Subject: Re: [PATCH bpf-next v2 1/6] mm, bpf: Introduce __GFP_TRYLOCK for opportunistic page allocation
Date: Thu, 12 Dec 2024 10:48:09 -0500 [thread overview]
Message-ID: <20241212104809.1c6cb0a1@batman.local.home> (raw)
In-Reply-To: <20241212153506.dT1MvukO@linutronix.de>
On Thu, 12 Dec 2024 16:35:06 +0100
Sebastian Sewior <bigeasy@linutronix.de> wrote:
> If NMI is one of the possible calling contexts, yes.
>
> One thing I am not 100% sure about is how "good" a spinlock_t trylock is
> if attempted from hardirq (on PREEMPT_RT). Obtaining the lock und
> unlocking is doable. The lock part will assign the "current" task as the
> task that owns the lock now. This task is just randomly on the CPU while
> the hardirq triggered. The regular spin_lock() will see this random task
> as the owner and might PI-boost it. This could work…
Looking at the unlock code, it and the slowtrylock() appears to use
raw_spin_lock_irqsave(). Hence it expects that it can be called from
irq disabled context. If it can be used in interrupt disabled context,
I don't see why it wouldn't work in actual interrupt context.
-- Steve
next prev parent reply other threads:[~2024-12-12 15:48 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-12-10 2:39 [PATCH bpf-next v2 0/6] bpf, mm: Introduce __GFP_TRYLOCK Alexei Starovoitov
2024-12-10 2:39 ` [PATCH bpf-next v2 1/6] mm, bpf: Introduce __GFP_TRYLOCK for opportunistic page allocation Alexei Starovoitov
2024-12-10 5:31 ` Matthew Wilcox
2024-12-10 9:05 ` Michal Hocko
2024-12-10 20:25 ` Shakeel Butt
2024-12-11 10:08 ` Michal Hocko
2024-12-10 22:06 ` Alexei Starovoitov
2024-12-11 10:19 ` Michal Hocko
2024-12-12 15:07 ` Sebastian Sewior
2024-12-12 15:21 ` Michal Hocko
2024-12-12 15:35 ` Sebastian Sewior
2024-12-12 15:48 ` Steven Rostedt [this message]
2024-12-12 16:00 ` Sebastian Sewior
2024-12-13 17:44 ` Steven Rostedt
2024-12-13 18:44 ` Alexei Starovoitov
2024-12-13 18:57 ` Alexei Starovoitov
2024-12-13 20:09 ` Steven Rostedt
2024-12-13 21:00 ` Steven Rostedt
2024-12-13 22:02 ` Alexei Starovoitov
2024-12-12 21:57 ` Alexei Starovoitov
2024-12-10 21:42 ` Alexei Starovoitov
2024-12-10 9:01 ` Sebastian Andrzej Siewior
2024-12-10 21:53 ` Alexei Starovoitov
2024-12-11 8:38 ` Vlastimil Babka
2024-12-12 2:14 ` Alexei Starovoitov
2024-12-12 8:54 ` Vlastimil Babka
2024-12-10 18:39 ` Vlastimil Babka
2024-12-10 22:42 ` Alexei Starovoitov
2024-12-11 8:48 ` Vlastimil Babka
2024-12-10 2:39 ` [PATCH bpf-next v2 2/6] mm, bpf: Introduce free_pages_nolock() Alexei Starovoitov
2024-12-10 8:35 ` Sebastian Andrzej Siewior
2024-12-10 22:49 ` Alexei Starovoitov
2024-12-12 14:44 ` Sebastian Andrzej Siewior
2024-12-12 19:57 ` Alexei Starovoitov
2024-12-11 10:11 ` Vlastimil Babka
2024-12-12 1:43 ` Alexei Starovoitov
2024-12-10 2:39 ` [PATCH bpf-next v2 3/6] locking/local_lock: Introduce local_trylock_irqsave() Alexei Starovoitov
2024-12-11 10:53 ` Vlastimil Babka
2024-12-11 11:55 ` Vlastimil Babka
2024-12-12 2:49 ` Alexei Starovoitov
2024-12-12 9:15 ` Vlastimil Babka
2024-12-13 14:02 ` Vlastimil Babka
2024-12-12 15:15 ` Sebastian Andrzej Siewior
2024-12-12 19:59 ` Alexei Starovoitov
2024-12-10 2:39 ` [PATCH bpf-next v2 4/6] memcg: Add __GFP_TRYLOCK support Alexei Starovoitov
2024-12-11 23:47 ` kernel test robot
2024-12-10 2:39 ` [PATCH bpf-next v2 5/6] mm, bpf: Use __GFP_ACCOUNT in try_alloc_pages() Alexei Starovoitov
2024-12-11 12:05 ` Vlastimil Babka
2024-12-12 2:54 ` Alexei Starovoitov
2024-12-10 2:39 ` [PATCH bpf-next v2 6/6] bpf: Use try_alloc_pages() to allocate pages for bpf needs Alexei Starovoitov
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