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b=qaZmBsMtlE03DE7uYyMpO1kH3Ux/UIj+d3TZ55psXgvie7qL/iaEUAXu7qkpdHWLCJOY5K 6Z4sS53We/EdoL0W1u1Lp5MpiaJIfxjxopHCyU/kXi8RenqWqApG/Iblcbd1bLsfXWv9dc xB4z24An3eDyptuXAe7PIOQlBhZtTWw= X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 01E5F40011 X-Rspam-User: Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=iu+LZTBS; spf=pass (imf04.hostedemail.com: domain of alexei.starovoitov@gmail.com designates 209.85.218.42 as permitted sender) smtp.mailfrom=alexei.starovoitov@gmail.com; dmarc=pass (policy=none) header.from=gmail.com X-Stat-Signature: toquswwkh8fzx6efy8e9cns6fd6u8az1 X-HE-Tag: 1657208690-6518 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000013, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Jul 7, 2022 at 3:28 AM Yafang Shao wrote: > > On Thu, Jul 7, 2022 at 8:07 AM Shakeel Butt wrote: > > > > On Wed, Jul 06, 2022 at 03:58:47PM +0000, Yafang Shao wrote: > > > GFP_ATOMIC doesn't cooperate well with memcg pressure so far, especially > > > if we allocate too much GFP_ATOMIC memory. For example, when we set the > > > memcg limit to limit a non-preallocated bpf memory, the GFP_ATOMIC can > > > easily break the memcg limit by force charge. So it is very dangerous to > > > use GFP_ATOMIC in non-preallocated case. One way to make it safe is to > > > remove __GFP_HIGH from GFP_ATOMIC, IOW, use (__GFP_ATOMIC | > > > __GFP_KSWAPD_RECLAIM) instead, then it will be limited if we allocate > > > too much memory. > > > > Please use GFP_NOWAIT instead of (__GFP_ATOMIC | __GFP_KSWAPD_RECLAIM). > > There is already a plan to completely remove __GFP_ATOMIC and mm-tree > > already have a patch for that. > > > > After reading the discussion[1], it looks good to me to use GFP_NOWAIT > instead. I will update it. Should we use GFP_ATOMIC | __GFP_NOMEMALLOC instead to align with its usage in the networking stack?