On Tue, 15 Sep 2020 15:56:35 +0800 <yanfei.xu@xxxxxxxxxxxxx> wrote:Thanks for your reply!
From: Yanfei Xu <yanfei.xu@xxxxxxxxxxxxx>
alloc_mask shouldn't inherit the current task's flags when
__alloc_pages_nodemask is invoked in interrupt.
...
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4889,7 +4889,8 @@ __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order, int preferred_nid,
* from a particular context which has been marked by
* memalloc_no{fs,io}_{save,restore}.
*/
- alloc_mask = current_gfp_context(gfp_mask);
+ if (!in_interrupt())
+ alloc_mask = current_gfp_context(gfp_mask);
ac.spread_dirty_pages = false;
/*
hm, yes, and perhaps other callsites in page_alloc.c.
I assume this doesn't actually make any runtime difference? Because
gfp_mask in interrupt contexts isn't going to have __GFP_IO or __GFP_FS
anyway.