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Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Johannes Weiner , Zi Yan , Uladzislau Rezki , "Vishal Moola (Oracle)" , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v1 2/2] vmalloc: Optimize vfree Message-ID: References: <20260105161741.3952456-1-ryan.roberts@arm.com> <20260105161741.3952456-3-ryan.roberts@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260105161741.3952456-3-ryan.roberts@arm.com> X-Rspam-User: X-Rspamd-Queue-Id: 24C3C1C0003 X-Rspamd-Server: rspam10 X-Stat-Signature: 4krb6aye1cqncd137mnbfebky848ee98 X-HE-Tag: 1767674190-103694 X-HE-Meta: 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 357pQc98 XJLCt5J3eXMUPdZXaWddwW7L5Q/dCk00tTfzACsWfMByIVMDLY9d34FZEq/WO9y5nZM97tIcC/rwCVivO6TmeZSCXntB8UQ8hQfp2blAZt0FMoaoOPtH4Ek6RaAbrDPFexbbYczk4ozFoxlsG6tzMiR8zzAGDOJP/1t1hGuIIBcPKLlezRVxD2Yfr3Q/GkqAfC21pc6kriQCbU0TAL6ECrlwm3xK1W0L9i2BQtzbA+vdcl7Z9EMQZGYoFIKgFT8s+d8ED6zZfZzBOBJpferwuew6GArrgZY/dvyYWFVTXcmgNBuFmSg05AwKDMCW6iqzvcC4Y X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Jan 05, 2026 at 04:17:38PM +0000, Ryan Roberts wrote: > + if (vm->nr_pages) { > + start_pfn = page_to_pfn(vm->pages[0]); > + nr = 1; > + for (i = 1; i < vm->nr_pages; i++) { > + unsigned long pfn = page_to_pfn(vm->pages[i]); > + > + if (start_pfn + nr != pfn) { > + __free_contig_range(start_pfn, nr); > + start_pfn = pfn; > + nr = 1; > + cond_resched(); > + } else { > + nr++; > + } It kind of feels like __free_contig_range() and this routine do the same thing -- iterate over each page and make sure that it's compatible with being freed. What if we did ... + for (i = 0; i < vm->nr_pages; i++) { + struct page *page = vm->pages[i]; + + if (!put_page_testzero(page)) { + __free_frozen_contig_pages(start_page, nr); + nr = 0; + continue; + } + + if (!nr) { + start_page = page; + nr = 1; + continue; + } + + if (start_page + nr != page) { + __free_frozen_contig_pages(start_page, nr); + start_page = page; + nr = 1; + cond_resched(); + } else { + nr++; + } + } + + __free_frozen_contig_pages(start_page, nr); That way we don't need to mess around with returning the number of pages not freed.