diff options
Diffstat (limited to 'Documentation/vm/transhuge.txt')
| -rw-r--r-- | Documentation/vm/transhuge.txt | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/Documentation/vm/transhuge.txt b/Documentation/vm/transhuge.txt index c4171e4519c2..cd28d5ee5273 100644 --- a/Documentation/vm/transhuge.txt +++ b/Documentation/vm/transhuge.txt @@ -110,6 +110,7 @@ MADV_HUGEPAGE region. echo always >/sys/kernel/mm/transparent_hugepage/defrag echo defer >/sys/kernel/mm/transparent_hugepage/defrag +echo defer+madvise >/sys/kernel/mm/transparent_hugepage/defrag echo madvise >/sys/kernel/mm/transparent_hugepage/defrag echo never >/sys/kernel/mm/transparent_hugepage/defrag @@ -120,10 +121,15 @@ that benefit heavily from THP use and are willing to delay the VM start to utilise them. "defer" means that an application will wake kswapd in the background -to reclaim pages and wake kcompact to compact memory so that THP is +to reclaim pages and wake kcompactd to compact memory so that THP is available in the near future. It's the responsibility of khugepaged to then install the THP pages later. +"defer+madvise" will enter direct reclaim and compaction like "always", but +only for regions that have used madvise(MADV_HUGEPAGE); all other regions +will wake kswapd in the background to reclaim pages and wake kcompactd to +compact memory so that THP is available in the near future. + "madvise" will enter direct reclaim like "always" but only for regions that are have used madvise(MADV_HUGEPAGE). This is the default behaviour. @@ -296,7 +302,7 @@ thp_split_page is incremented every time a huge page is split into base reason is that a huge page is old and is being reclaimed. This action implies splitting all PMD the page mapped with. -thp_split_page_failed is is incremented if kernel fails to split huge +thp_split_page_failed is incremented if kernel fails to split huge page. This can happen if the page was pinned by somebody. thp_deferred_split_page is incremented when a huge page is put onto split |