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b=YoO97zB5l64bkgGGRHVPrac5zt4TgQBHFw8dQ6KbkSJLpA8ekU6CJ+u+NzM8vAHU5 qntGXOzMdi7UI99ZlQ6uC5G8+plqCHWSg7kwDtggOLoW18k/GrwWpSOMd9o9OGd+o1 vccqzwUfqlnb4ySkhIN04iSfzLK6XSj8XdNC97tmzdWg3tDx5AFPF+6FXgrLkscngc TrHXsu8bGQtMio/5ceUpfT/TqSDXGvCggZNggvGYQELY2n2OJe08ZDUwPWiLzY/Icz 9BUSvn2jhfje8yUwI7NZy3xA7pXcdf25LYM/7ajs0JZDnMKmAYsfq4R7e9YMnDa+HD BazwhF0WgBzIA== Date: Mon, 19 Oct 2026 14:27:01 +0100 From: Harry Yoo To: Vitaly Wool Cc: akpm@linux-foundation.org, cl@gentwo.org, hao.li@linux.dev, hch@lst.de, linux-kernel@vger.kernel.org, linux-mm@kvack.org, nickolai@csail.mit.edu, rientjes@google.com, roman.gushchin@linux.dev, vbabka@kernel.org, vitaly.vul@partner.samsung.com Subject: Re: [PATCH v1] mempool: fix min_nr exceeding the elements array after concurrent resizes Message-ID: References: <20261018160315.1465504-1-vitaly.wool@konsulko.se> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Stat-Signature: ynx36zkbsfprnsegagx5e6k5tgiiq7oy X-Rspamd-Queue-Id: 7C5EE20011 X-Rspam-User: X-Rspamd-Server: rspam06 X-HE-Tag: 1792416424-31762 X-HE-Meta: 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 dYQ3neoH LbWeSVYVAGsOFqD4r8LXijzZZKS3B76cPrFoV//JPLbEx4w0UZBiBHSRBZdKcW9rZyim5x3aDTeqWkgCXyzq8rP2K8ecGO+X+gKUVG3oeZNrOG5LgsP4Y9AV3EBNdvmT1tNaFgJcSG935s02O5u0fpviYDq2vrexvE2Q2AC4lxLk8aN/5qj5qAmMsNYXYHMvRU7nCYILUoKHjm2SOSMMPzugFXNGBH4bN6dcAytdjYrlzYUo9aNmw0SDkCevoyUgKNaifloPCUr0g/mVWyOIu/No4AYtSMgAAvO1JbQ8cvX2DPJNPHWTWrba1iJFMGxxvx2rl1sebX1zgexjzK0RdeiLqO6/QNtUqEgGT Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Oct 19, 2026 at 08:45:55AM +0200, Vitaly Wool wrote: > > > > On Oct 18, 2026, at 6:15 PM, Harry Yoo wrote: > > > > On Sun, Oct 18, 2026 at 06:03:15PM +0200, Vitaly Wool wrote: > >>>> How about we take my patch [1] instead since > >>>> it isn't prone to this bug and is a nice optimization to the existing > >>>> mempool_resize() at the same time? > >>> > >>> It is not a good idea to squeeze a bug fix and an optimization > >>> into one patch. > >> > >> Generally speaking, yes. But that patch had been submitted before the fix > >> popped up, so there was no sqeezing per se. > > > > I mean the patch you've submitted does two things (wihch is not good). > > > > It should be split into two patches that 1) fixes the bug and 2) > > optimizes it. > > I don’t think this is a fair statement. I would say that the patch > I’ve submitted improves mempool_resize() to be rid of unnecessary > reallocations and data copying, and that (improved) implementation is > *not* prone to the race found in the previous version of this function. We backport bugfixes to -stable, but don't want to backport performance optimizations to -stable in general. -- Cheers, Harry / Hyeonggon