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From:   Joel Fernandes <joelaf@google.com>
Date:   Wed, 4 Apr 2018 21:12:52 -0700
Message-ID: <CAJWu+oqP64QzvPM6iHtzowek6s4p+3rb7WDXs1z51mwW-9mLbA@mail.gmail.com>
Subject: Re: [PATCH v1] kernel/trace:check the val against the available mem
To:     Matthew Wilcox <willy@infradead.org>
Cc:     Steven Rostedt <rostedt@goodmis.org>,
        Michal Hocko <mhocko@kernel.org>,
        Zhaoyang Huang <huangzhaoyang@gmail.com>,
        Ingo Molnar <mingo@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        kernel-patch-test@lists.linaro.org,
        Andrew Morton <akpm@linux-foundation.org>,
        "open list:MEMORY MANAGEMENT" <linux-mm@kvack.org>,
        Vlastimil Babka <vbabka@suse.cz>
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On Wed, Apr 4, 2018 at 7:58 PM, Matthew Wilcox <willy@infradead.org> wrote:
> On Wed, Apr 04, 2018 at 11:47:30AM -0400, Steven Rostedt wrote:
>> I originally was going to remove the RETRY_MAYFAIL, but adding this
>> check (at the end of the loop though) appears to have OOM consistently
>> kill this task.
>>
>> I still like to keep RETRY_MAYFAIL, because it wont trigger OOM if
>> nothing comes in and tries to do an allocation, but instead will fail
>> nicely with -ENOMEM.
>
> I still don't get why you want RETRY_MAYFAIL.  You know that tries
> *harder* to allocate memory than plain GFP_KERNEL does, right?  And
> that seems like the exact opposite of what you want.

No. We do want it to try harder but not if its already setup for failure.