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charset="UTF-8" ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1657673377; a=rsa-sha256; cv=none; b=FAYZUMpp+Hj1pJGLwi+FVNuBKY/wVxCdaCxedLZJCtn0Yh1GQElO1vZxa7jgz4xSDqUB/N BcDPuleSTBU7o+IzpTLVTIATMyOt9iAZ2/x5ZBklrymkx41UGGgVlg0n4Rgr32K35ls8VY xCxG6THe1v4WT+6DrqTTDim7rWcccHY= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=myyFuufK; spf=pass (imf24.hostedemail.com: domain of alexei.starovoitov@gmail.com designates 209.85.218.45 as permitted sender) smtp.mailfrom=alexei.starovoitov@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1657673377; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=wEW+uTd/RBYCxiEUkE6M+XESEKJryNMphRsuANsRi4o=; b=jZjZacOWdacGcmrUwI0JULeRIJJHr2ZyLP2tACEQzq+uJ3eJebAEjkNUYueEY8V/72ERPz rfzcuFo6VVzikT4MmT6Fv6109rIcSmCU4JbnBDWLQupYjPuKVlII38JSA/Dz16VxZAGEof lNr0wxvXB6H1qhnwFOQ/cFRx4udle/8= X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: E0823180074 X-Rspam-User: Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=myyFuufK; spf=pass (imf24.hostedemail.com: domain of alexei.starovoitov@gmail.com designates 209.85.218.45 as permitted sender) smtp.mailfrom=alexei.starovoitov@gmail.com; dmarc=pass (policy=none) header.from=gmail.com X-Stat-Signature: 5aw5ucyxbh3csf761ct7cpek1yz3p9f8 X-HE-Tag: 1657673376-360810 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, Jul 11, 2022 at 12:19 PM Shakeel Butt wrote: > > On Sat, Jul 9, 2022 at 8:45 AM 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. There's a plan to completely remove __GFP_ATOMIC in the > > mm side[1], so let's use GFP_NOWAIT instead. > > > > We introduced BPF_F_NO_PREALLOC is because full map pre-allocation is > > too memory expensive for some cases. That means removing __GFP_HIGH > > doesn't break the rule of BPF_F_NO_PREALLOC, but has the same goal with > > it-avoiding issues caused by too much memory. So let's remove it. > > > > This fix can also apply to other run-time allocations, for example, the > > allocation in lpm trie, local storage and devmap. So let fix it > > consistently over the bpf code > > > > It also fixes a typo in the comment. > > > > [1]. https://lore.kernel.org/linux-mm/163712397076.13692.4727608274002939094@noble.neil.brown.name/ > > > > Cc: Roman Gushchin > > Cc: Shakeel Butt > > Cc: NeilBrown > > Signed-off-by: Yafang Shao > > Reviewed-by: Shakeel Butt Applied to bpf-next.