Messages in this thread | | | Date | Fri, 09 Mar 2012 11:16:12 +0400 | From | Konstantin Khlebnikov <> | Subject | Re: [PATCH 3/7 v2] mm: rework __isolate_lru_page() file/anon filter |
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Hugh Dickins wrote: > On Thu, 8 Mar 2012, KAMEZAWA Hiroyuki wrote: >> On Tue, 6 Mar 2012 19:22:21 -0800 (PST) >> Hugh Dickins<hughd@google.com> wrote: >>> >>> What does the compiler say (4.5.1 here, OPTIMIZE_FOR_SIZE off)? >>> text data bss dec hex filename >>> 17723 113 17 17853 45bd vmscan.o.0 >>> 17671 113 17 17801 4589 vmscan.o.1 >>> 17803 113 17 17933 460d vmscan.o.2 >>> >>> That suggests that your v2 is the worst and your v1 the best. >>> Kame, can I persuade you to let the compiler decide on this? >>> >> >> Hmm. How about Costa' proposal ? as >> >> int tmp_var = PageActive(page) ? ISOLATE_ACTIVE : ISOLATE_INACTIVE >> if (!(mode& tmp_var)) >> ret; > > Yes, that would have been a good compromise (given a better name > than "tmp_var"!), I didn't realize that one was acceptable to you. > > But I see that Konstantin has been inspired by our disagreement to a > more creative solution. > > I like very much the look of what he's come up with, but I'm still > puzzling over why it barely makes any improvement to __isolate_lru_page(): > seems significantly inferior (in code size terms) to his original (which > I imagine Glauber's compromise would be equivalent to). > > At some point I ought to give up on niggling about this, > but I haven't quite got there yet.
(with if()) $ ./scripts/bloat-o-meter built-in.o built-in.o-v1 add/remove: 0/0 grow/shrink: 2/1 up/down: 32/-20 (12) function old new delta static.shrink_active_list 837 853 +16 shrink_inactive_list 1259 1275 +16 static.isolate_lru_pages 1055 1035 -20
(with switch()) $ ./scripts/bloat-o-meter built-in.o built-in.o-v2 add/remove: 0/0 grow/shrink: 4/2 up/down: 111/-23 (88) function old new delta __isolate_lru_page 301 377 +76 static.shrink_active_list 837 853 +16 shrink_inactive_list 1259 1275 +16 page_evictable 170 173 +3 __remove_mapping 322 319 -3 static.isolate_lru_pages 1055 1035 -20
(without __always_inline on page_lru()) $ ./scripts/bloat-o-meter built-in.o built-in.o-v5-noinline add/remove: 0/0 grow/shrink: 5/2 up/down: 93/-23 (70) function old new delta __isolate_lru_page 301 333 +32 isolate_lru_page 359 385 +26 static.shrink_active_list 837 853 +16 putback_inactive_pages 635 651 +16 page_evictable 170 173 +3 __remove_mapping 322 319 -3 static.isolate_lru_pages 1055 1035 -20
$ ./scripts/bloat-o-meter built-in.o built-in.o-v5 add/remove: 0/0 grow/shrink: 3/4 up/down: 35/-67 (-32) function old new delta static.shrink_active_list 837 853 +16 __isolate_lru_page 301 317 +16 page_evictable 170 173 +3 __remove_mapping 322 319 -3 mem_cgroup_lru_del 73 65 -8 static.isolate_lru_pages 1055 1035 -20 __mem_cgroup_commit_charge 676 640 -36
Actually __isolate_lru_page() even little bit bigger
> > Hugh
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