Messages in this thread |  | | Date | Thu, 21 Sep 2000 07:21:59 +0200 (CEST) | From | Mike Galbraith <> | Subject | Re: 2.4.0-test9-pre4: __alloc_pages(...) try_again: |
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On Wed, 20 Sep 2000, Roger Larsson wrote:
> Hi, > > > Trying to find out why test9-pre4 freezes with mmap002 > I added a counter for try_again loops. > > ... __alloc_pages(...) > > int direct_reclaim = 0; > unsigned int gfp_mask = zonelist->gfp_mask; > struct page * page = NULL; > + int try_again_loops = 0; > > - - - > > + printk("VM: sync kswapd (direct_reclaim: %d) try_again # > %d\n", > + direct_reclaim, ++try_again_loops); > wakeup_kswapd(1); > goto try_again; > > > Result was surprising: > direct_reclaim was 1. > try_again_loops did never stop increasing (note: it is not static, > and should restart from zero after each success) > > Why does this happen? > a) kswapd did not succeed in freeing a suitable page? > b) __alloc_pages did not succeed in grabbing the page?
Hi Roger,
A trace of locked up box shows endless repetitions of kswapd aparantly failing to free anything. What I don't see in the trace snippet below is reclaim_page(). I wonder if this test in __alloc_pages_limit() should include an || direct_reclaim.
if (z->free_pages + z->inactive_clean_pages > water_mark) { struct page *page = NULL; /* If possible, reclaim a page directly. */ if (direct_reclaim && z->free_pages < z->pages_min + 8) page = reclaim_page(z); /* If that fails, fall back to rmqueue. */ if (!page) page = rmqueue(z, order); if (page) return page; }
dmesg log after breakout: SysRq: Suspending trace SysRq: Show Memory Mem-info: Free pages: 1404kB ( 0kB HighMem) ( Active: 274, inactive_dirty: 49, inactive_clean: 0, free: 351 (255 510 765) ) 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 1*512kB 0*1024kB 0*2048kB = 512kB) 1*4kB 1*8kB 1*16kB 1*32kB 1*64kB 0*128kB 1*256kB 1*512kB 0*1024kB 0*2048kB = 892kB) = 0kB) Swap cache: add 470291, delete 470291, find 212689/658406 Free swap: 199024kB 32752 pages of RAM 0 pages of HIGHMEM 4321 reserved pages 296 pages shared 0 pages swap cached 0 pages in page table cache Buffer memory: 120kB SysRq: Terminate All Tasks
trace snippet: ........ c0134aa7 try_to_free_buffers +<13/130> (0.18) pid(3) c0134a47 sync_page_buffers +<13/60> (0.27) pid(3) c0117fb3 __wake_up +<13/144> (0.25) pid(3) c012dea9 __free_pages +<d/28> (0.26) pid(3) c0134aa7 try_to_free_buffers +<13/130> (0.16) pid(3) c0134a47 sync_page_buffers +<13/60> (0.33) pid(3) c0117fb3 __wake_up +<13/144> (0.25) pid(3) c012dea9 __free_pages +<d/28> (0.20) pid(3) c012cce7 free_shortage +<13/ac> (0.13) pid(3) c012df1e nr_free_pages +<e/3c> (0.16) pid(3) c012df5a nr_inactive_clean_pages +<e/40> (0.16) pid(3) c012df1e nr_free_pages +<e/3c> (0.21) pid(3) c014261d shrink_dcache_memory +<d/38> (0.24) pid(3) c0142280 prune_dcache +<10/120> (0.18) pid(3) c012a8ea kmem_cache_shrink +<e/58> (0.14) pid(3) c012a832 is_chained_kmem_cache +<e/60> (0.96) pid(3) c012a892 __kmem_cache_shrink +<e/58> (0.36) pid(3) c0143849 shrink_icache_memory +<d/38> (0.24) pid(3) c014375f prune_icache +<13/f0> (0.14) pid(3) c01432e4 sync_all_inodes +<10/120> (1.12) pid(3) c01435ef dispose_list +<f/68> (0.21) pid(3) c012a8ea kmem_cache_shrink +<e/58> (0.14) pid(3) c012a832 is_chained_kmem_cache +<e/60> (0.29) pid(3) c012a892 __kmem_cache_shrink +<e/58> (0.26) pid(3) c012cde3 refill_inactive +<13/128> (0.12) pid(3) c012cd8e inactive_shortage +<e/50> (0.14) pid(3) c012df1e nr_free_pages +<e/3c> (0.18) pid(3) c012df5a nr_inactive_clean_pages +<e/40> (0.23) pid(3) c012cce7 free_shortage +<13/ac> (0.13) pid(3) c012df1e nr_free_pages +<e/3c> (0.21) pid(3) c012df5a nr_inactive_clean_pages +<e/40> (0.16) pid(3) c012df1e nr_free_pages +<e/3c> (0.19) pid(3) c012af3b kmem_cache_reap +<13/1f0> (2.17) pid(3) c0117bb3 schedule +<13/400> (1.20) pid(3->5) c0109263 __switch_to +<13/cc> (0.69) pid(5) c0134c9f flush_dirty_buffers +<13/cc> (0.19) pid(5) c012df1e nr_free_pages +<e/3c> (0.16) pid(5) c012df5a nr_inactive_clean_pages +<e/40> (0.20) pid(5) c0117fb3 __wake_up +<13/144> (0.31) pid(5) c0117bb3 schedule +<13/400> (1.20) pid(5->141) c0109263 __switch_to +<13/cc> (0.41) pid(141) c0118d7d remove_wait_queue +<d/24> (0.40) pid(141) c012db24 __alloc_pages_limit +<10/b8> (0.35) pid(141) c012db24 __alloc_pages_limit +<10/b8> (0.23) pid(141) c012d0d2 wakeup_kswapd +<12/cc> (0.17) pid(141) c012db24 __alloc_pages_limit +<10/b8> (0.25) pid(141) c012d0d2 wakeup_kswapd +<12/cc> (0.16) pid(141) c0118d13 add_wait_queue +<f/38> (0.22) pid(141) c0117bb3 schedule +<13/400> (1.12) pid(141->144) c0109263 __switch_to +<13/cc> (0.38) pid(144) c0118d7d remove_wait_queue +<d/24> (0.33) pid(144) c012db24 __alloc_pages_limit +<10/b8> (0.22) pid(144) c012db24 __alloc_pages_limit +<10/b8> (0.20) pid(144) c012d0d2 wakeup_kswapd +<12/cc> (0.17) pid(144) c012db24 __alloc_pages_limit +<10/b8> (0.24) pid(144) c012d0d2 wakeup_kswapd +<12/cc> (0.16) pid(144) c0118d13 add_wait_queue +<f/38> (0.22) pid(144) c0117bb3 schedule +<13/400> (1.20) pid(144->1237) c0109263 __switch_to +<13/cc> (0.36) pid(1237) c0118d7d remove_wait_queue +<d/24> (0.33) pid(1237) c012db24 __alloc_pages_limit +<10/b8> (0.22) pid(1237) c012db24 __alloc_pages_limit +<10/b8> (0.20) pid(1237) c012d0d2 wakeup_kswapd +<12/cc> (0.17) pid(1237) c012db24 __alloc_pages_limit +<10/b8> (0.24) pid(1237) c012d0d2 wakeup_kswapd +<12/cc> (0.19) pid(1237) c0118d13 add_wait_queue +<f/38> (0.22) pid(1237) c0117bb3 schedule +<13/400> (1.08) pid(1237->194) c0109263 __switch_to +<13/cc> (0.37) pid(194) c0118d7d remove_wait_queue +<d/24> (0.31) pid(194) c012db24 __alloc_pages_limit +<10/b8> (0.22) pid(194) c012db24 __alloc_pages_limit +<10/b8> (0.20) pid(194) c012d0d2 wakeup_kswapd +<12/cc> (0.17) pid(194) c012db24 __alloc_pages_limit +<10/b8> (0.24) pid(194) c012d0d2 wakeup_kswapd +<12/cc> (0.16) pid(194) c0118d13 add_wait_queue +<f/38> (0.22) pid(194) c0117bb3 schedule +<13/400> (0.99) pid(194->99) c0109263 __switch_to +<13/cc> (0.38) pid(99) c0118d7d remove_wait_queue +<d/24> (0.31) pid(99) c012db24 __alloc_pages_limit +<10/b8> (0.22) pid(99) c012db24 __alloc_pages_limit +<10/b8> (0.20) pid(99) c012d0d2 wakeup_kswapd +<12/cc> (0.22) pid(99) c012db24 __alloc_pages_limit +<10/b8> (0.24) pid(99) c012d0d2 wakeup_kswapd +<12/cc> (0.16) pid(99) c0118d13 add_wait_queue +<f/38> (0.22) pid(99) c0117bb3 schedule +<13/400> (0.89) pid(99->218) c0109263 __switch_to +<13/cc> (0.38) pid(218) c0118d7d remove_wait_queue +<d/24> (0.31) pid(218) c012db24 __alloc_pages_limit +<10/b8> (0.22) pid(218) c012db24 __alloc_pages_limit +<10/b8> (0.20) pid(218) c012d0d2 wakeup_kswapd +<12/cc> (0.17) pid(218) c012db24 __alloc_pages_limit +<10/b8> (0.24) pid(218) c012d0d2 wakeup_kswapd +<12/cc> (0.18) pid(218) c0118d13 add_wait_queue +<f/38> (0.22) pid(218) c0117bb3 schedule +<13/400> (0.90) pid(218->1238) c0109263 __switch_to +<13/cc> (0.48) pid(1238) c0118d7d remove_wait_queue +<d/24> (0.31) pid(1238) c012db24 __alloc_pages_limit +<10/b8> (0.22) pid(1238) c012db24 __alloc_pages_limit +<10/b8> (0.20) pid(1238) c012d0d2 wakeup_kswapd +<12/cc> (0.17) pid(1238) c012db24 __alloc_pages_limit +<10/b8> (0.24) pid(1238) c012d0d2 wakeup_kswapd +<12/cc> (0.16) pid(1238) c0118d13 add_wait_queue +<f/38> (0.22) pid(1238) c0117bb3 schedule +<13/400> (0.53) pid(1238->3) c0109263 __switch_to +<13/cc> (0.35) pid(3) c012cbf3 refill_inactive_scan +<13/f4> (0.18) pid(3) c012b30d age_page_down_nolock +<d/28> (0.16) pid(3) c012b39b deactivate_page_nolock +<f/254> (0.40) pid(3) c012cbf3 refill_inactive_scan +<13/f4> (0.16) pid(3) c012b30d age_page_down_nolock +<d/28> (0.16) pid(3) c012b39b deactivate_page_nolock +<f/254> (0.32) pid(3) ..........
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