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h=Date:From:To:Cc:Subject:References:In-Reply-To; b=OEWBxu5KnEguBwQsJmXEOlLVlzd41WaccgHCS8VR/HX3KoqArK5AD3XyC4v/449Rw h4QokdvZhHHmCVVCXc1m12gHafV1segbzIfA8uFZKOjsWfIHlf8H6w2Xjd6HPlD+AF /4+OJEnpyV1GKW2Di/dSvT6HvNQrPdUwHpPzLfi0hik9/0VRnBU0/s8XkFkfu8by20 sQiCyOtUtmP0znCP62oXgEI4eEQLRsOwVNv2yNi3bWFZTys6z56zW5JhOYXOep6QrT CPvnTTDNz38OyCIF5AFykhFHD2yabhfoFfW4Tmg7oEZRK1RBBIaUzDU54/eXJV/VcC lwlYJJazkHi/Q== Date: Mon, 8 Jun 2026 09:17:02 +0100 From: Lorenzo Stoakes To: Imran Khan Cc: akpm@linux-foundation.org, 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-Rspamd-Queue-Id: 035C940006 X-Stat-Signature: wqumziyhaza49cwigrnm84kyhps6izut X-Rspamd-Server: rspam03 X-Rspam-User: X-HE-Tag: 1780906628-585352 X-HE-Meta: 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 iaT5lDZw YZeMU4PfWOX8JKwu16GbUaVtRlKMf0eLcW+Nrnkww1H2HyYigeSnZ33qzdWEYm/d9Soooe2NYTd2dF43xQf7F+gz/NBiwC/cYmhW6SFqQDuf3O1LUW1nVefllI1kOZlCVi6D7FiiUgB/ZpiqnSMXMFZMRtNzJb/3xTthnV9YRnnURBtBsTWmaPG8wDi37Yw3FKMD367fCXkDoYSFt0Fe/okcQxWuE9UkGBui6sQuJzxO33Zu5BUjOE2h0WDjRDXt0r6N+J5AujLIPFdLKO0WR/9qv5QEEjXCnzwEtOFs9DWHUzYc= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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 LGTM, so: Reviewed-by: Lorenzo Stoakes > --- > 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 > Cheers, Lorenzo