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b=EBYyKq4JCAW8GNUGiIHBtC4FTeUBGRM86DnzC8blZmSIdcNUJcW7DjTEGD710n+B+ U4evLNzQvWAC74XqMyk/+Fld2I9s2fyoYQxyeSgBa3xn++HxB4Iq6ftza8Mb+9yACZ tMb0Br1lnhUKLfdV8ifew9cxkHWyg3yDM4wHfKKMYZCzq0rkXX5kWCEpQfsq6Oqxoj H4HXAbk+EIBYO5MjajoMtf2roE5f6x9ZcUmh1CneSM/5sFklBy85el1M11qU4hUQ0m H+wVVuDcryGip/HPQ0Ew6QmcrcxLcC6YHk1SL3MD4kYsuAKrpk0V2ZG0EAH2D4cZ7a +Uzrsy2rRykPA== Message-ID: Date: Fri, 5 Jun 2026 14:14:02 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] mm/vmstat: avoid taking zone lock in /proc/buddyinfo reads Content-Language: en-US To: Imran Khan , akpm@linux-foundation.org, david@kernel.org, ljs@kernel.org, liam@infradead.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20260604134245.1580287-1-imran.f.khan@oracle.com> From: "Vlastimil Babka (SUSE)" Autocrypt: addr=vbabka@kernel.org; keydata= xsFNBFZdmxYBEADsw/SiUSjB0dM+vSh95UkgcHjzEVBlby/Fg+g42O7LAEkCYXi/vvq31JTB KxRWDHX0R2tgpFDXHnzZcQywawu8eSq0LxzxFNYMvtB7sV1pxYwej2qx9B75qW2plBs+7+YB 87tMFA+u+L4Z5xAzIimfLD5EKC56kJ1CsXlM8S/LHcmdD9Ctkn3trYDNnat0eoAcfPIP2OZ+ 9oe9IF/R28zmh0ifLXyJQQz5ofdj4bPf8ecEW0rhcqHfTD8k4yK0xxt3xW+6Exqp9n9bydiy tcSAw/TahjW6yrA+6JhSBv1v2tIm+itQc073zjSX8OFL51qQVzRFr7H2UQG33lw2QrvHRXqD Ot7ViKam7v0Ho9wEWiQOOZlHItOOXFphWb2yq3nzrKe45oWoSgkxKb97MVsQ+q2SYjJRBBH4 8qKhphADYxkIP6yut/eaj9ImvRUZZRi0DTc8xfnvHGTjKbJzC2xpFcY0DQbZzuwsIZ8OPJCc LM4S7mT25NE5kUTG/TKQCk922vRdGVMoLA7dIQrgXnRXtyT61sg8PG4wcfOnuWf8577aXP1x 6mzw3/jh3F+oSBHb/GcLC7mvWreJifUL2gEdssGfXhGWBo6zLS3qhgtwjay0Jl+kza1lo+Cv BB2T79D4WGdDuVa4eOrQ02TxqGN7G0Biz5ZLRSFzQSQwLn8fbwARAQABzSNWbGFzdGltaWwg QmFia2EgPHZiYWJrYUBrZXJuZWwub3JnPsLBsAQTAQoAWhYhBKlA1DSZLC6OmRA9UCJPp+fM gqZkBQJqFFy6GxSAAAAAAAQADm1hbnUyLDIuNSsxLjEyLDIsMgIbAwUJGtCBUAULCQgHAwUV CgkICwUWAgMBAAIeBQIXgAAKCRAiT6fnzIKmZJIUEADFx/tREzUImHrEwVHeSvDFmA7tJysI UVrlvrM09E7GIuzphzv7jYmo8n3ANpCczLEVr4G0syYQdTigaZgv3+FQDIIzhKih1IHhu1Ei XHlywNWKnQxxQEUNi5Mwx43wQz5XVw9F1A7gtKBKNtfogO511hAbrzagrYajyQacEJ/+sfhZ 9Da8ltHIXD8pcYaHUfQgEusCgmEd9+KrUwrTbckFKmYq5chuE6yJ4J0EmWknL096jIE6CnzF FRslQ3B1UKDjxVsm1ZHfir5NeWszLkTvGFsddFaWTgh8UycESG6VQzKXjjewXu2pG7YQYRpj QKm1W5X2TkwWkXRBZTmfmbhxIUMh3+zf5wQ463rSmDN/8v81tdqBtAW6rH/kzg1GvkaTHXn0 507yEHFzBksk2viAuIxxr7km8+/KARYLIdGtx30EG8cKzAUZOK6WqxtNCsXUJNrVE8CWrCaD icoNu7Fs1c5hmPHdSTnU48ce67449DdnO4neLSNhRiGlMHJgfJUmgrxu/hcYeOZ3haWmEQ2w uW1Mh01OHi8QZHCEyAbABrPs9GUgccc/4eYXX9hIgxfSkYzn8f+8NuIFPWl/0uTvjgqU29FQ SbzOLxHq9439Ox40G5mS5eZXRGxITYR+6TXvRGI6P/264jvflnr/pDGUttaikU+0W+1uxgKH cmYbEc7ATQRbGTU1AQgAn0H6UrFiWcovkh6EXVcl+SeqyO6JHOPm+e9Wu0Vw+VIUvXZVUVVQ La1PQDUi6j00ChlcR66g9/V0sPIcSutacPKfdKYOBvzd4rlhL8rfrdEsQw5ApZxrA8kYZVMh FmBRKAa6wos25moTlMKpCWzTH84+WO5+ziCTsTUZASAToz3RdunTD+vQcHj0GqNTPAHK63sf bAB2I0BslZkXkY1RLb/YhuA6E7JyEd2pilZOrIuBGl/5q2qSakgnAVFWFBR/DO27JuAksYnq +aH8vI0xGvwn75KqSk4UzAkDzWSmO4ZHuahKtQgZNsMYV+PGayRBX9b9zbldzopoLBdqHc4n jQARAQABwsF8BBgBCgAmAhsMFiEEqUDUNJksLo6ZED1QIk+n58yCpmQFAmfIHFQFCRYU6J8A CgkQIk+n58yCpmS2PA//bqN1LfcotmArgElsa+0EGZSQlYgK48pm8WAeTXTngudP9IJ4SuKY HR5RNjHcBeqN+Me0zxRqYzRb8nGanHEkDyf4Im8DQM8d6vbyU+FcPmG4skud4kgS1zMHnlVd SXfSIwKC/hKgdHG8aBV7545Lz9X6Iohea+94wneD0aw/hqF+QWewGZhWJriWAZtvEkzNjQOi 4U9F/trLten/x7bpphDSnDMKJtITbtzATT1Dq7o7VpIUK1nCTQALMuMjKCdi8OdU/+V+R3O4 0PXWvX8qrvqYapVbZ+9KqT74FsuB0Ya9uXwgBF2Q6cRuETZk5vqaqKxzqoQZCO8AOz/58j6O 2RHNy/mZEN+7tJ5Tsq42zVJ4jxsT8b9YplavCMsnBgDeRWhcbYhCyttoL7nYISyWg4kQYZ/P wIV3OuNv2f8iKYsxNsRuClOAF82+gvqOy1/1pprFjy8uo2pkoOrb63aOP3vO5VHnRKgra6dq NcaZ+c6J4H+nEJGi2SkHAUJz5oBzuThvPudLvPA/SK8sKoM01IRxSihev/S/5WLazXB1PGem OCbvzC1IjWJJraxiDJ5IygokapUa2RP7+WBR22skQ3SSl6G107QgWKSyTOGWEaRmV53vxQLV jXuCmzSSasTL60zq5yGrT4/DYQVSNEUiUbG4pYekxJujNeEDkUlky0Y= In-Reply-To: <20260604134245.1580287-1-imran.f.khan@oracle.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 49BA0C0009 X-Stat-Signature: mg9sx46y3sumimgja5hp1hjn7igmozhk X-Rspam-User: X-HE-Tag: 1780661647-237847 X-HE-Meta: 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 CyPeLERn voK+iScPsAJSy30Lz01KtQQ0kIAtUjuUrcNuADKi8kwL8oC0smAR4fvtghYtQVmVw266RS9c+Q4qzUqU8rLzItDnktLT9GLJfvbVIVBHiAtxhgf71V5Rv5Xh73XI5E0wcI1w9UGa57zBBhTxSfGCU+k6N641KvVRb6d/Dw0doV98VfLag3NmqmK+cizKigyt/CM++TCTJ8KD3Bx7msFZLUYBe5WN6ZsKZEwWV11AGX6j1pb0il79MH6L0YRaMVUx6M8p1narP009cx2leqs/FHnOBJbmppCffeLvysGMzMAYxREBWSJ3dIQ9G6A== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 6/4/26 15:42, Imran Khan wrote: > frag_show_print() just reads zone->free_area[order].nr_free, so > it can safely do this without needing the zone->lock. > > Pass nolock=true from frag_show(), so that walk_zones_in_node() > can skip the zone->lock acquisition. > > Signed-off-by: Imran Khan Acked-by: Vlastimil Babka (SUSE) > --- > mm/vmstat.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/vmstat.c b/mm/vmstat.c > index f534972f517de..7b93fbf9af092 100644 > --- a/mm/vmstat.c > +++ b/mm/vmstat.c > @@ -1568,7 +1568,7 @@ static void frag_show_print(struct seq_file *m, pg_data_t *pgdat, > static int frag_show(struct seq_file *m, void *arg) > { > pg_data_t *pgdat = (pg_data_t *)arg; > - walk_zones_in_node(m, pgdat, true, false, frag_show_print); > + walk_zones_in_node(m, pgdat, true, true, frag_show_print); > return 0; > } > > > base-commit: e43ffb69e0438cddd72aaa30898b4dc446f664f8