From: Christoph Hellwig <hch@lst•de>
To: Alexander Lobakin <aleksander.lobakin@intel•com>
Cc: Jesper Dangaard Brouer <hawk@kernel•org>,
Christoph Hellwig <hch@lst•de>,
Vlastimil Babka <vbabka@kernel•org>, Harry Yoo <harry@kernel•org>,
Andrew Morton <akpm@linux-foundation•org>,
Hao Li <hao.li@linux•dev>, Christoph Lameter <cl@gentwo•org>,
David Rientjes <rientjes@google•com>,
Roman Gushchin <roman.gushchin@linux•dev>,
linux-arm-msm@vger•kernel.org, dri-devel@lists•freedesktop.org,
freedreno@lists•freedesktop.org, linux-kernel@vger•kernel.org,
linux-mm@kvack•org, io-uring@vger•kernel.org,
kasan-dev@googlegroups•com, bpf@vger•kernel.org,
netdev@vger•kernel.org, Matt Fleming <mfleming@cloudflare•com>,
kernel-team <kernel-team@cloudflare•com>
Subject: Re: [PATCH] mm/slab: improve kmem_cache_alloc_bulk
Date: Wed, 27 May 2026 16:07:24 +0200 [thread overview]
Message-ID: <20260527140724.GA13256@lst.de> (raw)
In-Reply-To: <777c7229-4285-4c7c-9340-dfaebd2ab291@intel.com>
On Wed, May 27, 2026 at 03:56:38PM +0200, Alexander Lobakin wrote:
> >> - n -= kmem_cache_alloc_bulk(net_hotdata.skbuff_cache,
> >> - GFP_ATOMIC | __GFP_ZERO | __GFP_NOWARN,
> >> - n - nc->skb_count, &skbs[nc->skb_count]);
> >> + if (kmem_cache_alloc_bulk(net_hotdata.skbuff_cache,
> >> + GFP_ATOMIC | __GFP_ZERO | __GFP_NOWARN,
> >> + n - nc->skb_count, &skbs[nc->skb_count]))
> >> + n = nc->skb_count;
>
> kmem_cache_alloc_bulk() allocates `n - nc->skb_count`, but here you
> assign `nc->skb_count` to n.
> Ah wait,
>
> n -= n - nc->skb_count
> n = n - (n - nc->skb_count)
> n = n - n + nc->skb_count
> n = nc->skb_count
>
> Correct :D
Exactly the steps I went through when writing this patch :)
next prev parent reply other threads:[~2026-05-27 14:07 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-27 7:02 improve the kmem_cache_alloc_bulk API Christoph Hellwig
2026-05-27 7:02 ` [PATCH] mm/slab: improve kmem_cache_alloc_bulk Christoph Hellwig
2026-05-27 7:53 ` bot+bpf-ci
2026-05-27 8:51 ` Jesper Dangaard Brouer
2026-05-27 13:56 ` Alexander Lobakin
2026-05-27 14:07 ` Christoph Hellwig [this message]
2026-05-27 9:38 ` Vlastimil Babka (SUSE)
2026-05-27 12:20 ` Christoph Hellwig
2026-05-28 8:58 ` kernel test robot
2026-05-27 9:11 ` improve the kmem_cache_alloc_bulk API Vlastimil Babka (SUSE)
2026-05-27 12:21 ` Christoph Hellwig
2026-05-27 14:07 ` Vlastimil Babka (SUSE)
2026-05-28 9:05 ` Christoph Hellwig
2026-05-28 9:16 ` Vlastimil Babka (SUSE)
-- strict thread matches above, loose matches on Subject: below --
2026-05-28 9:34 improve the kmem_cache_alloc_bulk API v2 Christoph Hellwig
2026-05-28 9:34 ` [PATCH] mm/slab: improve kmem_cache_alloc_bulk Christoph Hellwig
2026-05-29 11:54 ` Vlastimil Babka (SUSE)
2026-05-29 13:50 ` Christoph Hellwig
2026-06-01 6:39 ` Harry Yoo
2026-06-01 8:16 ` Vlastimil Babka (SUSE)
2026-06-01 11:38 ` Christoph Hellwig
2026-06-01 12:50 ` Vlastimil Babka (SUSE)
2026-06-01 13:32 ` Rob Clark
2026-06-01 14:39 ` Rob Clark
2026-06-03 9:17 ` Vlastimil Babka (SUSE)
2026-06-03 11:13 ` Rob Clark
2026-06-03 16:22 ` Vlastimil Babka (SUSE)
2026-06-04 7:10 ` Harry Yoo
2026-06-04 7:35 ` Vlastimil Babka (SUSE)
2026-06-04 9:36 ` Rob Clark
2026-06-01 11:39 ` Harry Yoo
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