6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Michal Hocko <mhocko@xxxxxxxx> [ Upstream commit e9c3cda4d86e56bf7fe403729f38c4f0f65d3860 ] Gao Xiang has reported that the page allocator complains about high order __GFP_NOFAIL request coming from the vmalloc core: __alloc_pages+0x1cb/0x5b0 mm/page_alloc.c:5549 alloc_pages+0x1aa/0x270 mm/mempolicy.c:2286 vm_area_alloc_pages mm/vmalloc.c:2989 [inline] __vmalloc_area_node mm/vmalloc.c:3057 [inline] __vmalloc_node_range+0x978/0x13c0 mm/vmalloc.c:3227 kvmalloc_node+0x156/0x1a0 mm/util.c:606 kvmalloc include/linux/slab.h:737 [inline] kvmalloc_array include/linux/slab.h:755 [inline] kvcalloc include/linux/slab.h:760 [inline] it seems that I have completely missed high order allocation backing vmalloc areas case when implementing __GFP_NOFAIL support. This means that [k]vmalloc at al. can allocate higher order allocations with __GFP_NOFAIL which can trigger OOM killer for non-costly orders easily or cause a lot of reclaim/compaction activity if those requests cannot be satisfied. Fix the issue by falling back to zero order allocations for __GFP_NOFAIL requests if the high order request fails. Link: https://lkml.kernel.org/r/ZAXynvdNqcI0f6Us@xxxxxxxxxxxxxx Fixes: 9376130c390a ("mm/vmalloc: add support for __GFP_NOFAIL") Reported-by: Gao Xiang <hsiangkao@xxxxxxxxxxxxxxxxx> Link: https://lkml.kernel.org/r/20230305053035.1911-1-hsiangkao@xxxxxxxxxxxxxxxxx Signed-off-by: Michal Hocko <mhocko@xxxxxxxx> Reviewed-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx> Acked-by: Vlastimil Babka <vbabka@xxxxxxx> Cc: Baoquan He <bhe@xxxxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxx> Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Stable-dep-of: 8e0545c83d67 ("mm/vmalloc: fix vmalloc which may return null if called with __GFP_NOFAIL") Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- mm/vmalloc.c | 28 +++++++++++++++++++++++----- 1 file changed, 23 insertions(+), 5 deletions(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 67a10a04df041..cab30d9497e6b 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -2923,6 +2923,8 @@ vm_area_alloc_pages(gfp_t gfp, int nid, unsigned int order, unsigned int nr_pages, struct page **pages) { unsigned int nr_allocated = 0; + gfp_t alloc_gfp = gfp; + bool nofail = false; struct page *page; int i; @@ -2933,6 +2935,7 @@ vm_area_alloc_pages(gfp_t gfp, int nid, * more permissive. */ if (!order) { + /* bulk allocator doesn't support nofail req. officially */ gfp_t bulk_gfp = gfp & ~__GFP_NOFAIL; while (nr_allocated < nr_pages) { @@ -2971,20 +2974,35 @@ vm_area_alloc_pages(gfp_t gfp, int nid, if (nr != nr_pages_request) break; } + } else if (gfp & __GFP_NOFAIL) { + /* + * Higher order nofail allocations are really expensive and + * potentially dangerous (pre-mature OOM, disruptive reclaim + * and compaction etc. + */ + alloc_gfp &= ~__GFP_NOFAIL; + nofail = true; } /* High-order pages or fallback path if "bulk" fails. */ - while (nr_allocated < nr_pages) { if (fatal_signal_pending(current)) break; if (nid == NUMA_NO_NODE) - page = alloc_pages(gfp, order); + page = alloc_pages(alloc_gfp, order); else - page = alloc_pages_node(nid, gfp, order); - if (unlikely(!page)) - break; + page = alloc_pages_node(nid, alloc_gfp, order); + if (unlikely(!page)) { + if (!nofail) + break; + + /* fall back to the zero order allocations */ + alloc_gfp |= __GFP_NOFAIL; + order = 0; + continue; + } + /* * Higher order allocations must be able to be treated as * indepdenent small pages by callers (as they can with -- 2.43.0
