From: Christoph Hellwig <hch@infradead.org>
To: Mike Rapoport <rppt@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>,
Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org
Subject: Re: [PATCH] block: partitions: replace __get_free_page() with kmalloc()
Date: Mon, 25 May 2026 23:27:33 -0700 [thread overview]
Message-ID: <ahU9VQAxZE_jXi28@infradead.org> (raw)
In-Reply-To: <ahQX_JCgS9JWIhY-@kernel.org>
On Mon, May 25, 2026 at 12:35:56PM +0300, Mike Rapoport wrote:
> > This does, but it still fails to explain why kmalloc performs just as
> > well as __get_free_page(s) these days.
>
> I don't think that in this case - a single allocation on the cold path -
> the performance difference is even measurable.
Well, please state that.
> Nevertheless allocations from slab caches are way faster than
> __get_free_page() (i.e. alloc_pages()) as it's essentially lockless
> cmpxchg. Allocations that need to refill the cache do alloc_pages() with a
> little of slab bookkeeping overhead.
Please state that too.
prev parent reply other threads:[~2026-05-26 6:27 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-20 8:15 [PATCH] block: partitions: replace __get_free_page() with kmalloc() Mike Rapoport (Microsoft)
[not found] ` <ahPnX-CwVgK-9chp@infradead.org>
2026-05-25 6:52 ` Mike Rapoport
2026-05-25 7:16 ` Christoph Hellwig
2026-05-25 9:35 ` Mike Rapoport
2026-05-26 6:27 ` Christoph Hellwig [this message]
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