On Mon, Jul 24, 2017 at 05:45:35PM +0800, Hui Zhu wrote: > The first version is in [1]. > > Got -EBUSY from zs_page_migrate will make migration > slow (retry) or fail (zs_page_putback will schedule_work free_work, > but it cannot ensure the success). > > I noticed this issue because my Kernel patched [2] > that will remove retry in __alloc_contig_migrate_range. > This retry willhandle the -EBUSY because it will re-isolate the page > and re-call migrate_pages. > Without it will make cma_alloc fail at once with -EBUSY. > > According to the review from Minchan Kim in [3], I update the patch > to skip unnecessary loops but not return -EBUSY if zspage is not inuse. > > Following is what I got with highalloc-performance in a vbox with 2 > cpu 1G memory 512 zram as swap. And the swappiness is set to 100. > ori ne > orig new > Minor Faults 50805113 50830235 > Major Faults 43918 56530 > Swap Ins 42087 55680 > Swap Outs 89718 104700 > Allocation stalls 0 0 > DMA allocs 57787 52364 > DMA32 allocs 47964599 48043563 > Normal allocs 0 0 > Movable allocs 0 0 > Direct pages scanned 45493 23167 > Kswapd pages scanned 1565222 1725078 > Kswapd pages reclaimed 1342222 1503037 > Direct pages reclaimed 45615 25186 > Kswapd efficiency 85% 87% > Kswapd velocity 1897.101 1949.042 > Direct efficiency 100% 108% > Direct velocity 55.139 26.175 > Percentage direct scans 2% 1% > Zone normal velocity 1952.240 1975.217 > Zone dma32 velocity 0.000 0.000 > Zone dma velocity 0.000 0.000 > Page writes by reclaim 89764.000 105233.000 > Page writes file 46 533 > Page writes anon 89718 104700 > Page reclaim immediate 21457 3699 > Sector Reads 3259688 3441368 > Sector Writes 3667252 3754836 > Page rescued immediate 0 0 > Slabs scanned 1042872 1160855 > Direct inode steals 8042 10089 > Kswapd inode steals 54295 29170 > Kswapd skipped wait 0 0 > THP fault alloc 175 154 > THP collapse alloc 226 289 > THP splits 0 0 > THP fault fallback 11 14 > THP collapse fail 3 2 > Compaction stalls 536 646 > Compaction success 322 358 > Compaction failures 214 288 > Page migrate success 119608 111063 > Page migrate failure 2723 2593 > Compaction pages isolated 250179 232652 > Compaction migrate scanned 9131832 9942306 > Compaction free scanned 2093272 2613998 > Compaction cost 192 189 > NUMA alloc hit 47124555 47193990 > NUMA alloc miss 0 0 > NUMA interleave hit 0 0 > NUMA alloc local 47124555 47193990 > NUMA base PTE updates 0 0 > NUMA huge PMD updates 0 0 > NUMA page range updates 0 0 > NUMA hint faults 0 0 > NUMA hint local faults 0 0 > NUMA hint local percent 100 100 > NUMA pages migrated 0 0 > AutoNUMA cost 0% 0% > > [1]: https://lkml.org/lkml/2017/7/14/93 > [2]: https://lkml.org/lkml/2014/5/28/113 > [3]: https://lkml.org/lkml/2017/7/21/10 > > Signed-off-by: Hui Zhu <zhuhui@xxxxxxxxxx> > --- > mm/zsmalloc.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c > index d41edd2..c2c7ba9 100644 > --- a/mm/zsmalloc.c > +++ b/mm/zsmalloc.c > @@ -1997,8 +1997,11 @@ int zs_page_migrate(struct address_space *mapping, struct page *newpage, > > spin_lock(&class->lock); > if (!get_zspage_inuse(zspage)) { > - ret = -EBUSY; > - goto unlock_class; > + /* > + * Set "offset" to end of the page so that every loops > + * skips unnecessary object scanning. > + */ > + offset = PAGE_SIZE; > } > > pos = offset; > @@ -2066,7 +2069,7 @@ int zs_page_migrate(struct address_space *mapping, struct page *newpage, > } > } > kunmap_atomic(s_addr); > -unlock_class: > + Unncessary newline. Other than that, Looks good to me. Acked-by: Minchan Kim <minchan@xxxxxxxxxx> Thanks! -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
