| Message ID | 20220622064712.959479-1-yang.yang29@zte.com.cn (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm/page_alloc: make the annotations of available memory more accurate | expand |
On Wed, 22 Jun 2022 06:47:13 +0000 cgel.zte@gmail.com wrote: > From: Yang Yang <yang.yang29@zte.com.cn> > > Not all the systems use swap, so estimating available memory would > help to prevent swapping or OOM of system that not use swap. > > And we need to reserve some page cache to prevent swapping or > thrashing. If somebody is accessing the pages in pagecache, > and if too much would be freed, most accesses might mean > reading data from disk, i.e. thrashing. > > Signed-off-by: Yang Yang <yang.yang29@zte.com.cn> This should include your signoff, as described in Documentation/process/submitting-patches.rst. And we'd like a full name for that signoff please, not simply a bare email address.
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index e538dde2c1c0..233f68d31cdd 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5889,14 +5889,14 @@ long si_mem_available(void) /* * Estimate the amount of memory available for userspace allocations, - * without causing swapping. + * without causing swapping or OOM. */ available = global_zone_page_state(NR_FREE_PAGES) - totalreserve_pages; /* * Not all the page cache can be freed, otherwise the system will - * start swapping. Assume at least half of the page cache, or the - * low watermark worth of cache, needs to stay. + * start swapping or thrashing. Assume at least half of the page + * cache, or the low watermark worth of cache, needs to stay. */ pagecache = pages[LRU_ACTIVE_FILE] + pages[LRU_INACTIVE_FILE]; pagecache -= min(pagecache / 2, wmark_low);