From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: From: Hua Ji Subject: About 32M hash table Date: Sun, 10 Jun 2001 16:28:33 -0700 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Sender: owner-linux-mm@kvack.org Return-Path: To: linuxppc-user@lists.linuxppc.org, linuxppc-embedded@lists.linuxppc.org, linux-mm@kvack.org List-ID: Hi, folks, Got an issue. Thanks in advance. I tried to build a 32M page table for my 750-based system. From the linux ppc source codes(head.S or hashtable.S from the MVista Inc.), the **hash_page** function is the one who does the work. I tested with 256k page table size, it works. However, after I changed to 32M page table setting, the hashed value is not correct/same as I mannually get: Hash_Base = 0x8000000 //Hence, it is 32M aligned Hash_bits =19 //So that 26-19=7; In other words, the total 9 bits(7th-15th) frin primiary hash will get involved. From 256K page table, the Hash_bits is 12, which means the (26-12)th and 15th bits will be used for hash function. ---------------------- For example, when I map the 0x1d000000, the value calculated with specification would be: 0x08340040; But with the linux codes, the value is: 0x08740040, which was proved being wrong(I was able to get the exception when enabled the mmu. The only thing I assume for changing to 32M is the above :Hash_base and the Hash_bits. I guess I missed some points. Any advice is highly appreciated. Thanks, Mike -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/