The VM pressure notification flags have excluded GFP_KERNEL with the reasoning that user land will not be able to take any action in case of kernel memory being low. This is not true always. Consider the case of a user land program managing all the huge memory pages. By including GFP_KERNEL flag whenever the kernel memory is low, pressure notification can be send, and the manager process can split huge pages to satisfy kernel memory requirement. This is a common scanario in cloud. Most of the host memory is reserved as hugepages and can be broken down to small pages on demand. This is done to minimise fragmentation so that Virtual Machine power on will be successful always. Signed-off-by: Shaju Abraham <shaju.abraham@xxxxxxxxxxx> --- mm/vmpressure.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/vmpressure.c b/mm/vmpressure.c index 4bac22fe1aa2..7ccfb3dd8173 100644 --- a/mm/vmpressure.c +++ b/mm/vmpressure.c @@ -253,7 +253,8 @@ void vmpressure(gfp_t gfp, struct mem_cgroup *memcg, bool tree, * Indirect reclaim (kswapd) sets sc->gfp_mask to GFP_KERNEL, so * we account it too. */ - if (!(gfp & (__GFP_HIGHMEM | __GFP_MOVABLE | __GFP_IO | __GFP_FS))) + if (!(gfp & (__GFP_HIGHMEM | __GFP_MOVABLE | __GFP_IO | + __GFP_FS | GFP_KERNEL))) return; /* -- 2.20.1
