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b=ExvJXB+v5NznZQBp47/Q5VjnJbVvyitW4di3uIhPLvqvcUgc+0z2B60yf1qVsE0dS BUv2KdmSEXT0OLlTb8OhsHIet/1JuqBI8oXmooSbHRQNWhRjf2s2inpLIvbr2ovr4c nC2Yfyeld4wL1wfguV0GM/qXAkvtjYMGSZecdQJtU/WvWhxPt/WIGjttI1w4PNzPtu KL08bQyeWdNhBNaEDoxBC4MtRoVJp6QDVd8JlSY2FdwtUrA6IoMb252Yi8f1etWfUz uOwWVf3zAuLp4lXfFUnZ18xOrSAT6kc2KDIspAy2xg2jNzcmiAh0VPYoNQurIANxrm 6vXjIg42fhAJg== Date: Wed, 24 Jun 2026 08:16:50 +0100 From: Lorenzo Stoakes To: akpm@linux-foundation.org Cc: Imran Khan , david@kernel.org, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/vmstat: avoid taking zone lock in /proc/buddyinfo reads Message-ID: References: <20260604134245.1580287-1-imran.f.khan@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260604134245.1580287-1-imran.f.khan@oracle.com> X-Stat-Signature: mesypjzp6jwi94mmwi8f3jikntsob8cu X-Rspamd-Queue-Id: 4804CC000C X-Rspam-User: X-Rspamd-Server: rspam01 X-HE-Tag: 1782285419-831279 X-HE-Meta: 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 c1wBMQQU 9Cy05dkBOPs5+V6r1SqQRAxOxZtkfyf/hn8LbOmWFW+SZbH/bsU+0krfmSMcOoGkWzdFNPn3LRNXehzMPEiUHDGCjSlgJOu6yM4VnTYxqI6M44VYBTiLWh64bPimYxq4Gn0tET8tSLgTrSHFHstebNeOprz2lYBxU7v4KkEWIGl2yIUAsXCcJBfKUjXX84FK0VK8RDOhM4Ia6/k2rzPteoXmPh6FaKghPCpzJ4r9mUks5qvJpB+eyWdDdvJ/j+QrIj1+h5BiYIpWe4RX2sfNXHgDTYg== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hi Andrew, I think this one got missed last cycle? I don't see it in any mm- tree, and has a bunch of tags. I guess Imran will need to resend it at -rc1? Cheers, Lorenzo On Thu, Jun 04, 2026 at 09:42:45PM +0800, 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 > --- > 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 > -- > 2.34.1 >