On Fri, 2006-08-18 at 15:59 +0100, Alan Cox wrote: > Ar Gwe, 2006-08-18 am 12:52 +0400, ysgrifennodd Kirill Korotaev: > > > hmm, not sure why it is simpler. > > because introducing additonal lookups/hashes etc. is harder and > > adds another source for possible mistakes. > > we can always optimize it out if people insist (by cost of slower > > accounting). > > It ought to be cheap. Given each set of page structs is an array its a > simple subtract and divide (or with care and people try to pack them > nicely for cache lines - shift) to get to the parallel accounting array.
I wish page structs were just a simple array. ;) It will just be a bit more code, but we'll need this for the two other memory models: sparsemem and discontigmem. For discontig, we'll just need pointers in the pg_data_ts and, for sparsemem, we'll likely need another pointer in the 'struct mem_section'. This will effectively double the memory we need for sparsemem (because we only use one pointer per SECTION_SIZE bytes of memory) but, that should be just fine. Is there ever any need to go from the accounting structure *back* to the page? I guess that might be the hard part with keeping parallel arrays, if we even need it. The reverse lookups might introduce a bit more pain with sparsemem and discontig because, right now, we use bits in page->flags to help us go find the containing node or the correct mem_section for the page. -- Dave ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ ckrm-tech mailing list https://lists.sourceforge.net/lists/listinfo/ckrm-tech
