Messages in this thread | | | Date | Tue, 19 May 2009 12:48:32 +0800 | From | Wu Fengguang <> | Subject | Re: [PATCH 2/3] vmscan: make mapped executable pages the first class citizen |
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On Tue, May 19, 2009 at 12:44:19PM +0800, KOSAKI Motohiro wrote: > > > begin: 2479 2344 9659 210 0 579643 > > > end: 284 232010 234142 260 772776 20917184 > > > restore: 379 232159 234371 301 774888 20967849 > > > > > > The numbers show that > > > > > > - The startup pgmajfault of 2.6.30-rc4-mm is merely 1/3 that of 2.6.29. > > > I'd attribute that improvement to the mmap readahead improvements :-) > > > > > > - The pgmajfault increment during the file copy is 633-630=3 vs 260-210=50. > > > That's a huge improvement - which means with the VM_EXEC protection logic, > > > active mmap pages is pretty safe even under partially cache hot streaming IO. > > > > > > - when active:inactive file lru size reaches 1:1, their scan rates is 1:20.8 > > > under 10% cache hot IO. (computed with formula Dpgdeactivate:Dpgfree) > > > That roughly means the active mmap pages get 20.8 more chances to get > > > re-referenced to stay in memory. > > > > > > - The absolute nr_mapped drops considerably to 1/9 during the big IO, and the > > > dropped pages are mostly inactive ones. The patch has almost no impact in > > > this aspect, that means it won't unnecessarily increase memory pressure. > > > (In contrast, your 20% mmap protection ratio will keep them all, and > > > therefore eliminate the extra 41 major faults to restore working set > > > of zsh etc.) > > > > I'm surprised this. > > Why your patch don't protect mapped page from streaming io? > > I guess you use initlevel=5 and use only terminal, right? > if so, dropping some graphics component makes sense.
No, it's in pure console mode, no X running at all.
> > > > > I strongly hope reproduce myself, please teach me reproduce way. > > >
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