Centos 7.x: Physical buffer allocation
by zvivered from LinuxQuestions.org on (#4QPGG)
Hello,
Under Centos 7.x (64) I tried to allocate a 32MB contiguous physical memory with:
void *p = dma_alloc_coherent (NULL, 0x2000000, &DmaHandle, GFP_KERNEL);
Also tried:
void *p = __get_free_pages (GFP_KERNEL, __get_order (0x2000000));
In both cases I got p=0 and few error messages in dmesg.
It works fine if the size is 0x400000 (4MB).
Is there a solution without changing the kernel boot command line parameters ?
Thank you,
Zvika
Under Centos 7.x (64) I tried to allocate a 32MB contiguous physical memory with:
void *p = dma_alloc_coherent (NULL, 0x2000000, &DmaHandle, GFP_KERNEL);
Also tried:
void *p = __get_free_pages (GFP_KERNEL, __get_order (0x2000000));
In both cases I got p=0 and few error messages in dmesg.
It works fine if the size is 0x400000 (4MB).
Is there a solution without changing the kernel boot command line parameters ?
Thank you,
Zvika