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[91.12.97.29]) by smtp.gmail.com with ESMTPSA id h6sm14828393wrt.20.2021.06.09.04.19.29 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 09 Jun 2021 04:19:29 -0700 (PDT) Subject: Re: how to return a chunk of kernel .data to free mem ? To: jim.cromie@gmail.com, LKML , Linux Memory Management List , Jason Baron References: From: David Hildenbrand Organization: Red Hat Message-ID: <196e42a7-d50f-48e0-b4bd-e7f3701bfc6d@redhat.com> Date: Wed, 9 Jun 2021 13:19:29 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=VsDpANDq; spf=none (imf18.hostedemail.com: domain of david@redhat.com has no SPF policy when checking 170.10.133.124) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com X-Stat-Signature: 7crsebaa4oohwfb1ym81u4znnp8t8a77 X-Rspamd-Queue-Id: 7FE0E20010B7 X-Rspamd-Server: rspam06 X-HE-Tag: 1623237571-633812 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000004, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 05.06.21 16:50, jim.cromie@gmail.com wrote: > I have convinced DYNAMIC_DEBUG code to not need > about 15% of its __dyndbg section, about 30kb on my test kernel. > > This memory is not kmalloc'd, so krealloc wont work. > (I tried anyway, on a loaded module, it panicd) > > Is there a way to return a chunk of init .data memory to general use ? > > heres the patchset; > https://lore.kernel.org/lkml/20210529200029.205306-1-jim.cromie@gmail.com/ > Hm, you could try free_reserved_page(). But obviously, only full pages can be handed to the buddy. -- Thanks, David / dhildenb