2015-03-13 오후 9:12에 Roman Pen 이(가) 쓴 글: > Hello all. > > Recently I came across high fragmentation of vm_map_ram allocator: vmap_block > has free space, but still new blocks continue to appear. Further investigation > showed that certain mapping/unmapping sequence can exhaust vmalloc space. On > small 32bit systems that's not a big problem, cause purging will be called soon > on a first allocation failure (alloc_vmap_area), but on 64bit machines, e.g. > x86_64 has 45 bits of vmalloc space, that can be a disaster. I think the problem you comments is already known so that I wrote comments about it as "it could consume lots of address space through fragmentation". Could you tell me about your situation and reason why it should be avoided? > > Fixing this I also did some tweaks in allocation logic of a new vmap block and > replaced dirty bitmap with min/max dirty range values to make the logic simpler. > > I would like to receive comments on the following three patches. > > Thanks. > > Roman Pen (3): > mm/vmalloc: fix possible exhaustion of vmalloc space caused by > vm_map_ram allocator > mm/vmalloc: occupy newly allocated vmap block just after allocation > mm/vmalloc: get rid of dirty bitmap inside vmap_block structure > > mm/vmalloc.c | 94 ++++++++++++++++++++++++++++++++++-------------------------- > 1 file changed, 54 insertions(+), 40 deletions(-) > > Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > Cc: Nick Piggin <npiggin@xxxxxxxxx> > Cc: Eric Dumazet <edumazet@xxxxxxxxxx> > Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> > Cc: David Rientjes <rientjes@xxxxxxxxxx> > Cc: WANG Chao <chaowang@xxxxxxxxxx> > Cc: Fabian Frederick <fabf@xxxxxxxxx> > Cc: Christoph Lameter <cl@xxxxxxxxx> > Cc: Gioh Kim <gioh.kim@xxxxxxx> > Cc: Rob Jones <rob.jones@xxxxxxxxxxxxxxx> > Cc: linux-mm@xxxxxxxxx > Cc: linux-kernel@xxxxxxxxxxxxxxx > Cc: stable@xxxxxxxxxxxxxxx > -- 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>