Re: about kmap_high function

2001-07-05 Thread Stephen C. Tweedie
Hi, On Thu, Jul 05, 2001 at 10:28:35AM +0800, michaelc wrote: >Thank you very much for your kindly guide, and I have two question to ask >you, One question is, Is kmap_high intended to be called merely in the user >context, so the highmem pages are mapped into user process page

Re[2]: about kmap_high function

2001-07-04 Thread michaelc
Hi, Tuesday, July 03, 2001, 5:38:09 PM, you wrote: SCT> kmap_high is intended to be called routinely for access to highmem SCT> pages. It is coded to be as fast as possible as a result. TLB SCT> flushes are expensive, especially on SMP, so kmap_high tries hard to SCT> avoid unnecessary flush

Re: about kmap_high function

2001-07-04 Thread Paul Mackerras
Stephen C. Tweedie writes: > On Tue, Jul 03, 2001 at 10:47:20PM +1000, Paul Mackerras wrote: > > On PPC it is a bit different. Flushing a single TLB entry is > > relatively cheap - the hardware broadcasts the TLB invalidation on the > > bus (in most implementations) so there are no cross-calls r

Re: about kmap_high function

2001-07-03 Thread Stephen C. Tweedie
Hi, On Tue, Jul 03, 2001 at 10:47:20PM +1000, Paul Mackerras wrote: > Stephen C. Tweedie writes: > > On PPC it is a bit different. Flushing a single TLB entry is > relatively cheap - the hardware broadcasts the TLB invalidation on the > bus (in most implementations) so there are no cross-calls

Re: about kmap_high function

2001-07-03 Thread Paul Mackerras
Stephen C. Tweedie writes: > kmap_high is intended to be called routinely for access to highmem > pages. It is coded to be as fast as possible as a result. TLB > flushes are expensive, especially on SMP, so kmap_high tries hard to > avoid unnecessary flushes. The code assumes that flushing a s

Re: about kmap_high function

2001-07-03 Thread Stephen C. Tweedie
Hi, On Fri, Jun 29, 2001 at 03:06:01PM +0800, michaelc wrote: > I found that the kmap_high function didn't call __flush_tlb_one() > when it mapped a highmem page sucessfully, and I think it maybe > cause the problem that TLB may store obslete page table entries, but > the kmap_atomic() functi

about kmap_high function

2001-06-28 Thread michaelc
I found that the kmap_high function didn't call __flush_tlb_one() when it mapped a highmem page sucessfully, and I think it maybe cause the problem that TLB may store obslete page table entries, but the kmap_atomic() function do call the __flush_tlb_one(), someone tell me what's the differenc