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Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Johannes Weiner , Zi Yan , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/2] mm: replace custom bad page map ratelimiting logic Date: Tue, 11 Aug 2026 18:21:55 +0100 Message-ID: <20260811172156.356053-2-pfalcato@suse.de> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260811172156.356053-1-pfalcato@suse.de> References: <20260811172156.356053-1-pfalcato@suse.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Pre-Result: action=no action; module=replies; Message is reply to one we originated X-Rspamd-Action: no action X-Rspam-User: X-Rspamd-Queue-Id: CFE9F120011 X-Rspamd-Server: rspam07 X-Stat-Signature: crp9uik4n7t9ffbm1ga8mgxoyzqkaqex X-HE-Tag: 1786468935-176041 X-HE-Meta: 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 jiDRL2AQ oJPoKfdZJ8f9BjruenPY7I3xbLO86+Mmw8dBoO63mqGc/p+iIfMy92RGwNoCy085wtRtlPXFj/xEHlIH7FKhaLr4+XCSXCfyL1KPYHv6fd054z9T/1J9TRlV/EdzLZdcXoQ+T2S5rhqgpG2rUCUQ428na5rmowt/5lyXBKDgWntze6hEczJxj3zxTL/DehgEWU86Qb2RtddqHwSPNj+HY+GIicp4G+6sXbVCLvDjXIszTQOUyx0cimB3RnEx0X7BN0XmmQEGQIgXLylQ= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: The current logic (allow up to $BURST prints per minute) can be entirely replaced by the generic version in lib/ratelimit.c, used around the kernel. Do so. The only functional difference should be that the new logs will read something like: KERN_WARNING "print_bad_page_map: %d callbacks suppressed\n", ... But that should be fine enough. Signed-off-by: Pedro Falcato --- mm/memory.c | 30 +++--------------------------- 1 file changed, 3 insertions(+), 27 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 4134ac607ee0..b4be57b590ce 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -492,32 +492,8 @@ static inline void add_mm_rss_vec(struct mm_struct *mm, int *rss) add_mm_counter(mm, i, rss[i]); } -static bool is_bad_page_map_ratelimited(void) -{ - static unsigned long resume; - static unsigned long nr_shown; - static unsigned long nr_unshown; - - /* - * Allow a burst of 60 reports, then keep quiet for that minute; - * or allow a steady drip of one report per second. - */ - if (nr_shown == 60) { - if (time_before(jiffies, resume)) { - nr_unshown++; - return true; - } - if (nr_unshown) { - pr_alert("BUG: Bad page map: %lu messages suppressed\n", - nr_unshown); - nr_unshown = 0; - } - nr_shown = 0; - } - if (nr_shown++ == 0) - resume = jiffies + 60 * HZ; - return false; -} +/* Allow a burst of 60 bad page map reports per minute. */ +static DEFINE_RATELIMIT_STATE(bad_page_map_ratelimit, 60 * HZ, 60); static void ptval_bytes_to_hex_str(char *buf, size_t buf_size, const void *entry, size_t entry_size) { @@ -633,7 +609,7 @@ static void print_bad_page_map(struct vm_area_struct *vma, char entry_str[PTVAL_STR_MAX]; pgoff_t index, anon_index; - if (is_bad_page_map_ratelimited()) + if (!__ratelimit(&bad_page_map_ratelimit)) return; mapping = vma->vm_file ? vma->vm_file->f_mapping : NULL; -- 2.55.0