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b=R34x74x8E/GSFGWZ5m+9EbzgrAfdYbTSE5a1mEAPpvDlHh7KA0cPK10twzml4AXox 7CccmKY7KDDDm5SsgGpq7kW6Ubn2FQZO7xzsdqFJjxIcJnJ2UU04CNef7Wbp8bfbk8 TBB3AmDS0WgAopfq7uXn+Ln7NvzDtLvn7qeU7HeykjX5kahaDHvkeEF1jGTDBR6bRO rhu4Do/epOw+gBOnFza6HEuiUDEQtFX9NB976SI/ZMy+SJSYiNYIFwDW/9QiyYVCIU hykLIbl33cSoZut46KWf209FF+RhYPKnhwZeEc24xCft+6DTLvcyN5yBI00ASMxOwF M3d++d7AV3B/g== Date: Wed, 23 Apr 2025 05:12:06 -1000 From: Tejun Heo To: Suren Baghdasaryan Cc: Andrew Morton , gaoxu , Dennis Zhou , Christoph Lameter , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , yipengxiang Subject: Re: mm: percpu: increase PERCPU_MODULE_RESERVE to avoid allocation failure Message-ID: References: <20250422170209.a8beaa8a3610d2e92421476f@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: AE74740009 X-Rspam-User: X-Rspamd-Server: rspam07 X-Stat-Signature: 596ypjnn1ece8coqcdy7iorphr4j3rbh X-HE-Tag: 1745421128-57129 X-HE-Meta: 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 LzxP1Ifr HxlIVsytgbV6waOw/nvi9mj7BHNHwNJaA1mXVtDFhzNZcjU1kUREzyPjU00ORm6kFXSrXOWBHGl26opv5X4Vgtmj6+03cKhtUiA56A+Bb5II7SR70uqumD7DLigAoK3Vz0fxWh5BnYGfD7u6CjNxWxI5kNaxw8JuFhSPs1Mb+7jj5gGdB/sokgatpWcht/yeDcyN3yWoYsZUKJRqIZsRvWZIpAqSzJaTJRfVPiLBLmVMVriIJvrAX1w3WfZI8wYNQkLTTLtNAOCldaUbjcCnMdCZWLdYBQrTa+q2ElfYnB/RSTPU= 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: List-Subscribe: List-Unsubscribe: On Tue, Apr 22, 2025 at 05:19:31PM -0700, Suren Baghdasaryan wrote: ... > Allocating this reserved area dynamically would be ideal. OTOH this > change increases the area size from 64kb to 128kb. Don't know how much > effort we should put into it. The easiest solution would be switching the modules to use alloc_percpu() instead of declaring per-cpu variables statically. I couldn't think of a better way to support static percpu variables in modules and still can't, but there aren't noticeable downsides to using dynamically allocated percpu variables, so if you have several bytes here and there, sure, declare them statically, but for anything chunky, please use dynamic allocations. Thanks. -- tejun