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DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1755225923; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=Ied7X9jQgR3h26+VkaXChRgVV0OEH9AE3P2+5XZf8hg=; b=sXcGpxlGLJlXlGMqaGdOaOw37qJdpzNs2klMzvD3Lg2noAzkvPpfC87kjEHPgG9ynR8rGy YUD+zNGUbmZZj/dzvZ2fvCpymFoYONIvIiTkPdK12DLRa8FsJA5Hm0fKB82xu/gF74MqKJ ZFioUKEWLNxNYjOXPp3e0uSYYNz2eW4= From: Ye Liu To: Andrew Morton , Vlastimil Babka Cc: Ye Liu , Johannes Weiner , Zi Yan , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH v3] mm/page_alloc: simplify lowmem_reserve max calculation Date: Fri, 15 Aug 2025 10:45:09 +0800 Message-ID: <20250815024509.37900-1-ye.liu@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam03 X-Rspam-User: X-Rspamd-Queue-Id: 89C9C100003 X-Stat-Signature: jjac88w47q7dp4brpngobao8kju51toj X-HE-Tag: 1755225924-507141 X-HE-Meta: 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 iQbfjefw nLphTqb3+tVDk8lKHZOdq75QQiFfXmCf38VC2bVFi0WZWkipD8TDb07x2jyBhUSpfJxy9j2Ds3hBSeQtv9WIzZTFl4DCFHSxHz8C5K50LC1piwgArCdnAzU0QHiTzhwuGo9Ayz4GlNbTM2ac5LEVaG4M0hFm5UNkXb8TQOlJLR6BQ76xoImq/1gX0CSOD54vaJMK61tNvzFZrqQKUpdN6dIAoLKUVbe873MOsVl0IHY9neynJ7hxY9gcF/oGFXtOmDaluwZcJhe4dtwZJXZCl1rtrDJS2hrN69SU8s5d1x7If8/lfKp5ndZgF8qjAVNCerjfw2PUuK2TdTj/w43oppHMLa9VF77adybmX 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: From: Ye Liu Use max() to find the maximum lowmem_reserve value and min_t() to cap it to managed_pages in calculate_totalreserve_pages(), instead of open-coding the comparisons. No functional change. Signed-off-by: Ye Liu Acked-by: Johannes Weiner Acked-by: Zi Yan Changes in v3: - max = min_t(unsigned long, max, managed_pages); - Link to v2:https://lore.kernel.org/all/20250815023500.36893-1-ye.liu@linux.dev/ Changes in v2: - Drop unnecessary braces - Replace "if (max > managed_pages)" with min_t() - Link to v1:https://lore.kernel.org/all/20250814090053.22241-1-ye.liu@linux.dev/ --- mm/page_alloc.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 64872214bc7d..eff07323987c 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -6235,16 +6235,13 @@ static void calculate_totalreserve_pages(void) unsigned long managed_pages = zone_managed_pages(zone); /* Find valid and maximum lowmem_reserve in the zone */ - for (j = i; j < MAX_NR_ZONES; j++) { - if (zone->lowmem_reserve[j] > max) - max = zone->lowmem_reserve[j]; - } + for (j = i; j < MAX_NR_ZONES; j++) + max = max(max, zone->lowmem_reserve[j]); /* we treat the high watermark as reserved pages. */ max += high_wmark_pages(zone); - if (max > managed_pages) - max = managed_pages; + max = min_t(unsigned long, max, managed_pages); pgdat->totalreserve_pages += max; -- 2.43.0