* Re: [PATCH] ppc64: 64K pages support [not found] ` <1130916198.20136.17.camel@gaston> @ 2005-11-05 0:38 ` Christoph Hellwig 2005-11-05 0:44 ` Benjamin Herrenschmidt 0 siblings, 1 reply; 3+ messages in thread From: Christoph Hellwig @ 2005-11-05 0:38 UTC (permalink / raw) To: Benjamin Herrenschmidt Cc: Andrew Morton, linuxppc64-dev, Linus Torvalds, Linux Kernel list, linux-mm So how does the 64k on 4k hardware emulation work? When Hugh did bigger softpagesize for x86 based on 2.4.x he had to fix drivers all over to deal with that. -- 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/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] ppc64: 64K pages support 2005-11-05 0:38 ` [PATCH] ppc64: 64K pages support Christoph Hellwig @ 2005-11-05 0:44 ` Benjamin Herrenschmidt 2005-11-05 6:37 ` Dave Airlie 0 siblings, 1 reply; 3+ messages in thread From: Benjamin Herrenschmidt @ 2005-11-05 0:44 UTC (permalink / raw) To: Christoph Hellwig Cc: Andrew Morton, linuxppc64-dev, Linus Torvalds, Linux Kernel list, linux-mm On Sat, 2005-11-05 at 01:38 +0100, Christoph Hellwig wrote: > So how does the 64k on 4k hardware emulation work? When Hugh did > bigger softpagesize for x86 based on 2.4.x he had to fix drivers all > over to deal with that. What was the problem with drivers ? On ppc64, it's all hidden in the arch code. All the kernel sees is a 64k page size. I extended the PTE to contain tracking informations for the 16 sub pages (HPTE bits & hash slot index). Sub pages are faulted on demand and flushed all at once, but it's all transparent to the generic code. Ben. -- 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/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] ppc64: 64K pages support 2005-11-05 0:44 ` Benjamin Herrenschmidt @ 2005-11-05 6:37 ` Dave Airlie 0 siblings, 0 replies; 3+ messages in thread From: Dave Airlie @ 2005-11-05 6:37 UTC (permalink / raw) To: Benjamin Herrenschmidt Cc: Christoph Hellwig, Andrew Morton, linuxppc64-dev, Linus Torvalds, Linux Kernel list, linux-mm > What was the problem with drivers ? On ppc64, it's all hidden in the > arch code. All the kernel sees is a 64k page size. I extended the PTE to > contain tracking informations for the 16 sub pages (HPTE bits & hash > slot index). Sub pages are faulted on demand and flushed all at once, > but it's all transparent to the generic code. > We did that with the VAX port about 5 years ago :-), granted for different reasons.. The VAX has 512 byte hw pages, we had to make a 4K pagesize for the kernel by grouping 8 hw pages together and hiding it all in the arch dir.. granted I don't know if it broke any drivers, we didn't have any... Dave. -- 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/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 3+ messages in thread
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2005-11-05 0:38 ` [PATCH] ppc64: 64K pages support Christoph Hellwig
2005-11-05 0:44 ` Benjamin Herrenschmidt
2005-11-05 6:37 ` Dave Airlie
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