From: Vlastimil Babka <vbabka@suse.cz>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: 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>,
Sebastian Sewior <bigeasy@linutronix.de>,
Steven Rostedt <rostedt@goodmis.org>,
Hou Tao <houtao1@huawei.com>,
Johannes Weiner <hannes@cmpxchg.org>,
shakeel.butt@linux.dev, Michal Hocko <mhocko@suse.com>,
Matthew Wilcox <willy@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>, Tejun Heo <tj@kernel.org>,
linux-mm <linux-mm@kvack.org>, Kernel Team <kernel-team@fb.com>,
Jann Horn <jannh@google.com>
Subject: Re: [PATCH bpf-next v2 3/6] locking/local_lock: Introduce local_trylock_irqsave()
Date: Fri, 13 Dec 2024 15:02:06 +0100 [thread overview]
Message-ID: <b67b1a0c-194a-4dd4-bc83-271e6388208f@suse.cz> (raw)
In-Reply-To: <60fadf5a-4c96-43b3-8cc2-baf71eb93e3f@suse.cz>
On 12/12/24 10:15, Vlastimil Babka wrote:
> On 12/12/24 03:49, Alexei Starovoitov wrote:
>> I like your
>> +struct local_tryirq_lock
>> approach, but let's put it in local_lock.h ?
>
> Sure, that was a proof of concept so kept it local.
>
>> and it probably needs local_inc_return() instead of READ/WRITE_ONCE.
>> With irq and nmis it's racy.
>
> Hm guess you are right, thanks!
>
Ah I remember now, the idea was that if an irq or nmi interrupts someone
else between checking that active is 0 and setting it to 1, it will finish
the critical section and unlock before the interrupted context can continue,
so the race is harmless.
next prev parent reply other threads:[~2024-12-13 14:02 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
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 [this message]
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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