Messages in this thread |  | | Subject | Re: [PATCH] net: decnet: Replace GFP_ATOMIC with GFP_KERNEL in dn_route_init | From | Jia-Ju Bai <> | Date | Mon, 9 Apr 2018 22:48:38 +0800 |
| |
On 2018/4/9 22:44, Eric Dumazet wrote: > > On 04/09/2018 07:10 AM, Jia-Ju Bai wrote: >> dn_route_init() is never called in atomic context. >> >> The call chain ending up at dn_route_init() is: >> [1] dn_route_init() <- decnet_init() >> decnet_init() is only set as a parameter of module_init(). >> >> Despite never getting called from atomic context, >> dn_route_init() calls __get_free_pages() with GFP_ATOMIC, >> which waits busily for allocation. >> GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL, >> to avoid busy waiting and improve the possibility of sucessful allocation. >> >> This is found by a static analysis tool named DCNS written by myself. >> And I also manually check it. >> >> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com> >> --- >> net/decnet/dn_route.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/net/decnet/dn_route.c b/net/decnet/dn_route.c >> index 0bd3afd..59ed12a 100644 >> --- a/net/decnet/dn_route.c >> +++ b/net/decnet/dn_route.c >> @@ -1898,7 +1898,7 @@ void __init dn_route_init(void) >> while(dn_rt_hash_mask & (dn_rt_hash_mask - 1)) >> dn_rt_hash_mask--; >> dn_rt_hash_table = (struct dn_rt_hash_bucket *) >> - __get_free_pages(GFP_ATOMIC, order); >> + __get_free_pages(GFP_KERNEL, order); >> } while (dn_rt_hash_table == NULL && --order > 0); >> >> if (!dn_rt_hash_table) >> > This might OOM under pressure.
Sorry, I do not understand this. Could you please explain the reason?
> This would need __GFP_NOWARN | __GFP_NORETRY I guess, and would target net-next >
Do you mean __get_free_pages(__GFP_NOWARN | __GFP_NORETRY) or __get_free_pages(__GFP_NOWARN | __GFP_NORETRY | GFP_KERNEL)?
Best wishes, Jia-Ju Bai
|  |