linux-kernel - Re: [PATCH v3] kmemleaak: survive in a low-memory situation

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Message-ID: <20540be2-5961-ea86-1ad8-50fbb4d15c6e@lca.pw>
Date:   Tue, 26 Mar 2019 12:28:14 -0400
From:   Qian Cai <cai@....pw>
To:     Christopher Lameter <cl@...ux.com>
Cc:     akpm@...ux-foundation.org, catalin.marinas@....com,
        mhocko@...nel.org, penberg@...nel.org, rientjes@...gle.com,
        iamjoonsoo.kim@....com, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] kmemleaak: survive in a low-memory situation



On 3/26/19 12:00 PM, Christopher Lameter wrote:
>> +		 */
>> +		gfp = (in_atomic() || irqs_disabled()) ? GFP_ATOMIC :
>> +		       gfp_kmemleak_mask(gfp) | __GFP_DIRECT_RECLAIM;
>> +		object = kmem_cache_alloc(object_cache, gfp);
>> +	}
>> +
>>  	if (!object) {
> 
> If the alloc must succeed then this check is no longer necessary.

Well, GFP_ATOMIC could still fail. It looks like the only thing that will never
fail is (__GFP_DIRECT_RECLAIM | __GFP_NOFAIL) as it keeps retrying in
__alloc_pages_slowpath().