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To: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,T_SCC_BODY_TEXT_LINE, T_SPF_PERMERROR autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org I'm running on CentOS7 on a 5.3 based kernel. I have CMA configured into the kernel and attempting to manipulate the amount of memory reserved via the "cma" boot parameter. I have one system with 32GB of memory of which I'm able to reserve 16GB for CMA. However, on another system that has over 512GB of memory, I can only reserve up to 8GB for CMA. My question is, why am I not able to reserve a larger CMA region on my 512GB memory system as compared to my other system where I could effectively reserve half of the DRAM space? Thanks in advance for any advice or pointers to where I might be able to find an explanation. Eric Pilmore