Messages in this thread | | | From | KOSAKI Motohiro <> | Subject | Re: [RFC] high system time & lock contention running large mixed workload | Date | Fri, 4 Dec 2009 09:36:21 +0900 (JST) |
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> On Tue, 2009-12-01 at 21:20 -0500, Rik van Riel wrote: > > > This is reasonable, except for the fact that pages that are moved > > to the inactive list without having the referenced bit cleared are > > guaranteed to be moved back to the active list. > > > > You'll be better off without that excess list movement, by simply > > moving pages directly back onto the active list if the trylock > > fails. > > > > > The attached patch addresses this issue by changing page_check_address() > to return -1 if the spin_trylock() fails and page_referenced_one() to > return 1 in that path so the page gets moved back to the active list. > > Also, BTW, check this out: an 8-CPU/16GB system running AIM 7 Compute > has 196491 isolated_anon pages. This means that ~6140 processes are > somewhere down in try_to_free_pages() since we only isolate 32 pages at > a time, this is out of 9000 processes... > > > --------------------------------------------------------------------- > active_anon:2140361 inactive_anon:453356 isolated_anon:196491 > active_file:3438 inactive_file:1100 isolated_file:0 > unevictable:2802 dirty:153 writeback:0 unstable:0 > free:578920 slab_reclaimable:49214 slab_unreclaimable:93268 > mapped:1105 shmem:0 pagetables:139100 bounce:0 > > Node 0 Normal free:1647892kB min:12500kB low:15624kB high:18748kB > active_anon:7835452kB inactive_anon:785764kB active_file:13672kB > inactive_file:4352kB unevictable:11208kB isolated(anon):785964kB > isolated(file):0kB present:12410880kB mlocked:11208kB dirty:604kB > writeback:0kB mapped:4344kB shmem:0kB slab_reclaimable:177792kB > slab_unreclaimable:368676kB kernel_stack:73256kB pagetables:489972kB > unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 > > 202895 total pagecache pages > 197629 pages in swap cache > Swap cache stats: add 6954838, delete 6757209, find 1251447/2095005 > Free swap = 65881196kB > Total swap = 67354616kB > 3997696 pages RAM > 207046 pages reserved > 1688629 pages shared > 3016248 pages non-shared
This seems we have to improve reclaim bale out logic. the system already have 1.5GB free pages. IOW, the system don't need swap-out anymore.
> @@ -352,9 +359,11 @@ static int page_referenced_one(struct page *page, > if (address == -EFAULT) > goto out; > > - pte = page_check_address(page, mm, address, &ptl, 0); > + pte = page_check_address(page, mm, address, &ptl, 0, trylock); > if (!pte) > goto out; > + else if (pte == (pte_t *)-1) > + return 1; > > /* > * Don't want to elevate referenced for mlocked page that gets this far,
Sorry, NAK. I have to say the same thing of Rik's previous mention. shrink_active_list() ignore the return value of page_referenced(). then above 'return 1' is meaningless.
Umm, ok, I'll make the patch myself.
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