On Mon, Jan 21, 2013 at 02:15:49PM +1100, paul.szabo@xxxxxxxxxxxxx wrote: > When calculating amount of dirtyable memory, min_free_kbytes should be > subtracted because it is not intended for dirty pages. So what's the effect for user? It would be better to include that in description if possible. > > Using an "extern int" because that is the only interface to some such > sysctl values. > > (This patch does not solve the PAE OOM issue.) > > Paul Szabo psz@xxxxxxxxxxxxxxxxx http://www.maths.usyd.edu.au/u/psz/ > School of Mathematics and Statistics University of Sydney Australia > > Reported-by: Paul Szabo <psz@xxxxxxxxxxxxxxxxx> > Reference: http://bugs.debian.org/695182 > Signed-off-by: Paul Szabo <psz@xxxxxxxxxxxxxxxxx> > > --- mm/page-writeback.c.old 2012-12-06 22:20:40.000000000 +1100 > +++ mm/page-writeback.c 2013-01-21 13:57:05.000000000 +1100 > @@ -343,12 +343,16 @@ > unsigned long determine_dirtyable_memory(void) > { > unsigned long x; > + extern int min_free_kbytes; > > x = global_page_state(NR_FREE_PAGES) + global_reclaimable_pages(); > > if (!vm_highmem_is_dirtyable) > x -= highmem_dirtyable_memory(x); > > + /* Subtract min_free_kbytes */ > + x -= min(x, min_free_kbytes >> (PAGE_SHIFT - 10)); It seems you saw old kernel. Current kernel includes following logic. static unsigned long global_dirtyable_memory(void) { unsigned long x; x = global_page_state(NR_FREE_PAGES) + global_reclaimable_pages(); x -= min(x, dirty_balance_reserve); if (!vm_highmem_is_dirtyable) x -= highmem_dirtyable_memory(x); return x + 1; /* Ensure that we never return 0 */ } And dirty_lanace_reserve already includes high_wmark_pages. Look at calculate_totalreserve_pages. So I think we don't need this patch. Thanks. > + > return x + 1; /* Ensure that we never return 0 */ > } > > -- > 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> -- Kind regards, Minchan Kim -- 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>