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b=nEpgm35VwgTPK6SizgtKr+wENMcoYcGcjH843yv496ZgG2seRLPfxhRODnZNGZT5n Sr1LnIcX7Ww/BJNf4wFMNGaTW7AiU7qOrV2aT2wlJlf1OeU9aMEfHmEE03JYOJiZnv qgMZxrjrBzXUdKsNkkIFk6rHF4xtkEFAoDsgIB2s= Date: Wed, 26 Feb 2025 15:00:54 -0800 From: Andrew Morton To: Gabriel Krisman Bertazi Cc: Michal Hocko , linux-mm@kvack.org, Mel Gorman , Vlastimil Babka , Baoquan He Subject: Re: [PATCH] Revert "mm/page_alloc.c: don't show protection in zone's ->lowmem_reserve[] for empty zone" Message-Id: <20250226150054.a40db3fb41148b10da9bdca6@linux-foundation.org> In-Reply-To: <87h64gsnd5.fsf@mailhost.krisman.be> References: <20250226032258.234099-1-krisman@suse.de> <87h64gsnd5.fsf@mailhost.krisman.be> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 0C6BC40016 X-Stat-Signature: pwzikzgg3kbjzpgd6y8iatgxksuazimh X-Rspam-User: X-HE-Tag: 1740610855-309416 X-HE-Meta: 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 4rT6eS58 TYS5tuyLHJQZa79iWUfEglPQ5XzZ+9KPa7PDp2N00vwv99PajrbAwBo5/qGN6bIfNtUxWym7S8lFbrppdZc3IJ7jpS80qCNJrgYh/I5DRglW3a4ISbcWm+oVtvtMRgrXW6IFRfmEjkaEJ/KxF4lOCKigf9sV2yZH9eqS437A2VCijJ8av3sLYB0Y3KFk5WxZEcmXGheWxuNwwaE+dmgWBNIWvvLmZjymmmRpIfp5EaDHKLdn2DTEv28Dc81+Hb16OJZb7rw8r0lTeUIaNTMrjJllH6FEW4I487JW7w6wJaOLD0Kc= 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 Wed, 26 Feb 2025 11:05:10 -0500 Gabriel Krisman Bertazi wrote: > For reference, I collected vmstat with and without this patch on a > freshly booted system running intensive randread io from an nvme for 5 > minutes. I got: > > rpm-6.12.0-slfo.1.2 -> pgscan_kswapd 5629543865 > Patched -> pgscan_kswapd 33580844 > > 33M scans is similar to what we had in kernels predating this patch. > These numbers is fairly representative of the workload on this machine, as > measured in several runs. So we are talking about a 2-order of > magnitude increase. Thanks for adding this detail - I pasted it into the changelog. I'll queue the patch with a cc:stable. You may wish to send along a new changelog to fill in additional details resulting from the review discussion.