Hi, prodyut hazarika wrote: >> +choice >> + prompt "Page size" >> + depends on 44x && PPC32 >> + default PPC32_4K_PAGES >> + help >> + The PAGE_SIZE definition. Increasing the page size may >> + improve the system performance in some dedicated cases. >> + If unsure, set it to 4 KB. >> + >> > You should mention an example of dedicated cases (eg. RAID). > I think this help should mention that for page size 256KB, you will > need to have a special version of binutils, since the ELF standard > mentions page sizes only upto 64KB. >
Agreed. >> -#ifdef CONFIG_PPC_64K_PAGES >> +#if defined(CONFIG_PPC32_256K_PAGES) >> +#define PAGE_SHIFT 18 >> +#elif defined(CONFIG_PPC32_64K_PAGES) || defined(CONFIG_PPC_64K_PAGES) >> #define PAGE_SHIFT 16 >> +#elif defined(CONFIG_PPC32_16K_PAGES) >> +#define PAGE_SHIFT 14 >> #else >> #define PAGE_SHIFT 12 >> #endif >> > > Why should the new defines be inside CONFIG_PPC_64K_PAGES? The > I think you missed first '-' on the first line. > definition CONFIG_PPC_64K_PAGES is repeated. > Shouldn't these defines be like this: > #if defined(CONFIG_PPC32_256K_PAGES) > #define PAGE_SHIFT 18 > #elif defined(CONFIG_PPC32_64K_PAGES) || defined(CONFIG_PPC_64K_PAGES) > #define PAGE_SHIFT 16 > #elif defined(CONFIG_PPC32_16K_PAGES) > #define PAGE_SHIFT 14 > #else > #define PAGE_SHIFT 12 > #endif > And they do actually :) > Please change PPC44x_PGD_OFF_SH to PPC44x_PGD_OFF_SHIFT. SH sounds > very confusing. I don't like the MI and M2 names too. Change > PPC44x_RPN_M2 to PPC44x_RPN_MASK. Change M1 to MASK in > PPC44x_PGD_OFF_M1 and PPC44x_PTE_ADD_M1 . > Agreed. > Is there no way a define like > #define PPC44x_PGD_OFF_SH (32 - PMD_SHIFT + 2) > be used in assembly file. If yes, we can avoid repeating the defines. > We can use defined like this, problem is that PMD_SHIFT and PTE_SHIFT declared inside #ifndef __ASSEMBLY__ > I think these 44x specific defines should go to asm/mmu-44x.h since I > Agreed. > For 256KB page size, I cannot understand why PTE_SHIFT is 11. Since > each PTE entry is 8 byte, PTE_SHIFT should have been 15. But then > there would be no bits in the Effective address for the 1st level > PGDIR offset. On what basis PTE_SHIFT of 11 is chosen? This overflow > problem happens only for 256KB page size. > I think Yuri has commented on this already. Any comments on the issues mentioned in introductory message? Regards, Ilya. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
