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SubjectRe: [PATCH 3/7 v2] mm: rework __isolate_lru_page() file/anon filter
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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