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[71.184.117.43]) by smtp.gmail.com with ESMTPSA id e4sm855103qkg.6.2019.03.26.09.28.15 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 26 Mar 2019 09:28:15 -0700 (PDT) Subject: Re: [PATCH v3] kmemleaak: survive in a low-memory situation To: Christopher Lameter Cc: akpm@linux-foundation.org, catalin.marinas@arm.com, mhocko@kernel.org, penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20190326154338.20594-1-cai@lca.pw> <01000169babb99b8-b583bf57-5104-45b7-a4d6-e7677c64ece2-000000@email.amazonses.com> From: Qian Cai Message-ID: <20540be2-5961-ea86-1ad8-50fbb4d15c6e@lca.pw> Date: Tue, 26 Mar 2019 12:28:14 -0400 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:60.0) Gecko/20100101 Thunderbird/60.3.3 MIME-Version: 1.0 In-Reply-To: <01000169babb99b8-b583bf57-5104-45b7-a4d6-e7677c64ece2-000000@email.amazonses.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Bogosity: Ham, tests=bogofilter, spamicity=0.000006, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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().