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From: Roman Gushchin <roman.gushchin@linux.dev>
To: Matthew Wilcox <willy@infradead.org>
Cc: Christoph Lameter <cl@linux.com>,
	linux-mm@kvack.org, cgroups@vger.kernel.org
Subject: Re: cgroups: warning for metadata allocation with GFP_NOFAIL (was Re: folio_alloc_buffers() doing allocations > order 1 with GFP_NOFAIL)
Date: Tue, 14 Nov 2023 09:29:00 -0800	[thread overview]
Message-ID: <ZVOuXOaPn_eCxaLY@P9FQF9L96D.corp.robot.car> (raw)
In-Reply-To: <ZVKnx2eCsOqLipG0@casper.infradead.org>

On Mon, Nov 13, 2023 at 10:48:39PM +0000, Matthew Wilcox wrote:
> On Mon, Nov 13, 2023 at 11:48:57AM -0800, Christoph Lameter wrote:
> > On Fri, 10 Nov 2023, Matthew Wilcox wrote:
> > 
> > > > Maybe Christoph is playing with min_slab_order or something, so we're
> > > > getting 8 pages per slab.  That's still only 2496 bytes.  Why are we
> > > > calling into the large kmalloc path?  What's really going on here?
> > > 
> > > Christoph?
> > 
> > Sorry I thought I already answered that.
> > 
> > This was a boot with slub_min_order=5 that was inadvertently left in from a
> > performance test.
> 
> Ah.  So do you think we need to fix this?

I'd leave the fix, so that we don't have to look into this "problem" next time.
But I'm not inclined to work on a proper fix: fixing the slab accounting
for this non-trivial setup. Maybe we should add a note into a doc saying that
raising slub_min_order might affect the slab accounting precision?


      reply	other threads:[~2023-11-14 17:29 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-11-01  0:13 folio_alloc_buffers() doing allocations > order 1 with GFP_NOFAIL Christoph Lameter (Ampere)
2023-11-01  8:08 ` Matthew Wilcox
2023-11-07  2:57   ` cgroups: warning for metadata allocation with GFP_NOFAIL (was Re: folio_alloc_buffers() doing allocations > order 1 with GFP_NOFAIL) Christoph Lameter
2023-11-07 18:05     ` Roman Gushchin
2023-11-07 18:18       ` Shakeel Butt
2023-11-08 10:33       ` Michal Hocko
2023-11-09  6:37         ` Shakeel Butt
2023-11-09 17:36           ` Roman Gushchin
2023-11-07 19:24     ` Matthew Wilcox
2023-11-07 21:33       ` Roman Gushchin
2023-11-07 21:37         ` Matthew Wilcox
2023-11-10 13:38       ` Matthew Wilcox
2023-11-13 19:48         ` Christoph Lameter
2023-11-13 22:48           ` Matthew Wilcox
2023-11-14 17:29             ` Roman Gushchin [this message]

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