From: Sergey Senozhatsky <senozhatsky@chromium.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Petr Mladek <pmladek@suse.com>,
Sergey Senozhatsky <senozhatsky@chromium.org>,
Luis Chamberlain <mcgrof@kernel.org>,
david@redhat.com, patches@lists.linux.dev,
linux-modules@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, petr.pavlu@suse.com,
prarit@redhat.com, gregkh@linuxfoundation.org, rafael@kernel.org,
christophe.leroy@csgroup.eu, tglx@linutronix.de, song@kernel.org,
rppt@kernel.org, willy@infradead.org, vbabka@suse.cz,
mhocko@suse.com, dave.hansen@linux.intel.com
Subject: Re: [PATCH 4/7] sempahore: add a helper for a concurrency limiter
Date: Fri, 31 Mar 2023 12:42:09 +0900 [thread overview]
Message-ID: <20230331034209.GA12892@google.com> (raw)
In-Reply-To: <CAHk-=wgF34MkhZnM_Kc1zggTWCAQ=BzEgAaAbE5wDM07bWiYeg@mail.gmail.com>
On (23/03/30 09:23), Linus Torvalds wrote:
> Although we also do have some other issues - I think down_trylock() is
> ok in irq contexts, but mutex_trylock() is not. Maybe that's why
> printk uses semaphores? I forget.
Yes, correct. IIRC we also cannot safely call mutex_unlock() from IRQ
context because it takes some internal mutex spin_lock in a non-IRQ-safe
manner. Semaphore is OK in this regard, both semaphore try_lock() and
unlock() can be called from IRQ.
next prev parent reply other threads:[~2023-03-31 3:42 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-29 5:31 [PATCH 0/7] module: avoid userspace pressure on unwanted allocations Luis Chamberlain
2023-03-29 5:31 ` [PATCH 1/7] module: move finished_loading() Luis Chamberlain
2023-03-29 5:31 ` [PATCH 2/7] module: extract patient module check into helper Luis Chamberlain
2023-03-29 5:31 ` [PATCH 3/7] module: avoid allocation if module is already present and ready Luis Chamberlain
2023-03-29 5:31 ` [PATCH 4/7] sempahore: add a helper for a concurrency limiter Luis Chamberlain
2023-03-29 7:21 ` Peter Zijlstra
2023-03-29 7:51 ` Luis Chamberlain
2023-03-29 9:19 ` Peter Zijlstra
2023-03-29 9:49 ` Luis Chamberlain
2023-03-29 10:14 ` Peter Zijlstra
2023-03-29 16:50 ` Linus Torvalds
2023-03-30 11:56 ` Peter Zijlstra
2023-03-30 16:23 ` Linus Torvalds
2023-03-31 3:42 ` Sergey Senozhatsky [this message]
2023-03-31 8:05 ` Petr Mladek
2023-03-31 3:45 ` Luis Chamberlain
2023-03-31 4:06 ` Matthew Wilcox
2023-03-31 4:13 ` Luis Chamberlain
2023-03-31 4:11 ` Sergey Senozhatsky
2023-03-29 5:31 ` [PATCH 5/7] modules/kmod: replace implementation with a sempahore Luis Chamberlain
2023-03-29 5:31 ` [PATCH 6/7] debugfs: add debugfs_create_atomic64_t for atomic64_t Luis Chamberlain
2023-03-29 5:46 ` Greg KH
2023-03-29 5:31 ` [PATCH 7/7] module: add debug stats to help identify memory pressure Luis Chamberlain
2023-03-29 5:46 ` Greg KH
2023-03-29 6:04 ` Luis Chamberlain
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