From: Guo Ren <guoren@kernel.org>
To: Michal Hocko <mhocko@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Guenter Roeck <linux@roeck-us.net>,
Linux List Kernel Mailing <linux-kernel@vger.kernel.org>
Subject: Re: Linux 5.0-rc1 (test results)
Date: Wed, 9 Jan 2019 00:16:59 +0800 [thread overview]
Message-ID: <20190108161659.GA26358@guoren-Inspiron-7460> (raw)
In-Reply-To: <20190108154031.GB343@dhcp22.suse.cz>
Thx Michal,
On Tue, Jan 08, 2019 at 04:40:31PM +0100, Michal Hocko wrote:
> On Tue 08-01-19 17:51:07, Guo Ren wrote:
> [...]
> > static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm)
> > {
> > pte_t *pte;
> > unsigned long i;
> >
> > pte = (pte_t *) __get_free_page(GFP_KERNEL | __GFP_RETRY_MAYFAIL);
> > ^^^^^^^^^^^^^^^^^^^
> > It's necessary ?
> > x86 & arm don't use
> > it.
> > if (!pte)
> > return NULL;
>
> That depends on whether you want OOM killer to be triggered for these
> allocations. If you add the flag then the allocation bails out with a
> failure rather than kill an oom victim.
Yes, in page_alloc.c:
if (gfp_mask & __GFP_RETRY_MAYFAIL)
goto out;
...
if (out_of_memory(&oc) || WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL)) {
^^^^^^^^^^^^^ OOM kill victim
...
if (gfp_mask & __GFP_NOFAIL)
page = __alloc_pages_cpuset_fallback(gfp_mask, order,
ALLOC_NO_WATERMARKS, ac);
}
Seems it could affect the behavior of the system which is out of memory.
OOM killer could help to get_page for current. So keep the same as x86 &
arm here. I'll remove __GFP_RETRY_MAYFAIL in patch.
Best Regards
Guo Ren
next prev parent reply other threads:[~2019-01-08 16:17 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-07 2:14 Linux 5.0-rc1 Linus Torvalds
2019-01-07 5:07 ` linux-next: stats (was: Linux 5.0-rc1) Stephen Rothwell
2019-01-07 19:26 ` Linux 5.0-rc1 (test results) Guenter Roeck
2019-01-07 23:21 ` Linus Torvalds
2019-01-08 9:51 ` Guo Ren
2019-01-08 15:40 ` Michal Hocko
2019-01-08 16:16 ` Guo Ren [this message]
2019-01-08 17:29 ` Michal Hocko
2019-02-09 19:42 ` Linux 5.0-rc1 Paul Bolle
2019-02-11 0:01 ` isdn
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