From: Thomas Gleixner <tglx@linutronix.de>
To: Vlastimil Babka <vbabka@suse.cz>,
kernel test robot <oliver.sang@intel.com>,
Shanker Donthineni <sdonthineni@nvidia.com>
Cc: oe-lkp@lists.linux.dev, lkp@intel.com,
linux-kernel@vger.kernel.org, Marc Zyngier <maz@kernel.org>,
Michael Walle <michael@walle.cc>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Hans de Goede <hdegoede@redhat.com>,
Wolfram Sang <wsa+renesas@sang-engineering.com>,
linux-mm@kvack.org, "Liam R. Howlett" <Liam.Howlett@oracle.com>,
Matthew Wilcox <willy@infradead.org>,
David Rientjes <rientjes@google.com>,
Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@kernel.org>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Hyeonggon Yoo <42.hyeyoo@gmail.com>,
Roman Gushchin <roman.gushchin@linux.dev>
Subject: Re: mm, slab/slub: Ensure kmem_cache_alloc_bulk() is available early
Date: Tue, 07 Feb 2023 19:20:31 +0100 [thread overview]
Message-ID: <87edr1uykw.ffs@tglx> (raw)
In-Reply-To: <8b7762c3-02be-a5c9-1c4d-507cfb51a15c@suse.cz>
On Tue, Feb 07 2023 at 15:47, Vlastimil Babka wrote:
> From 340d7c7b99f3e67780f6dec480ed1d27e6f325eb Mon Sep 17 00:00:00 2001
> From: Vlastimil Babka <vbabka@suse.cz>
> Date: Tue, 7 Feb 2023 15:34:53 +0100
> Subject: [PATCH] mm, slab/slub: remove notes that bulk alloc/free needs
> interrupts enabled
>
> The slab functions kmem_cache_[alloc|free]_bulk() have been documented
> as requiring interrupts to be enabled, since their addition in 2015.
> It's unclear whether that was a fundamental restriction, or an attempt
> to save some cpu cycles by not having to save and restore the irq
> flags.
I don't think so. The restriction is rather meant to avoid huge
allocations in atomic context which causes latencies and also might
deplete the atomic reserves.
So I rather avoid that and enforce !ATOMIC mode despite the
local_irq_save/restore() change which is really only to accomodate with
early boot.
Thanks,
tglx
next prev parent reply other threads:[~2023-02-07 18:20 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <202302011308.f53123d2-oliver.sang@intel.com>
2023-02-01 13:27 ` [PATCH 5/5] genirq: Use the maple tree for IRQ descriptors management Thomas Gleixner
2023-02-06 14:24 ` Vlastimil Babka
2023-02-06 18:10 ` Thomas Gleixner
2023-02-07 10:30 ` Thomas Gleixner
2023-02-07 14:16 ` mm, slab/slub: Ensure kmem_cache_alloc_bulk() is available early Thomas Gleixner
2023-02-07 14:45 ` Vlastimil Babka
2023-02-07 14:47 ` Vlastimil Babka
2023-02-07 18:20 ` Thomas Gleixner [this message]
2023-02-08 9:15 ` Vlastimil Babka
2023-02-08 20:46 ` Thomas Gleixner
2023-02-09 20:28 ` Matthew Wilcox
2023-02-09 23:19 ` Thomas Gleixner
2023-02-08 13:20 ` Hyeonggon Yoo
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