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[73.223.190.181]) by smtp.gmail.com with ESMTPSA id w189-20020a627bc6000000b0053e61633057sm8524481pfc.132.2022.09.13.18.53.24 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Tue, 13 Sep 2022 18:53:25 -0700 (PDT) From: Joe Damato To: x86@kernel.org, linux-mm@kvack.org, Ben Segall , Daniel Bristot de Oliveira , Dietmar Eggemann , "H. Peter Anvin" , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Mel Gorman , Steven Rostedt , Valentin Schneider Cc: Joe Damato Subject: [RFC 0/1] mm: Track per-task tlb events Date: Tue, 13 Sep 2022 18:51:08 -0700 Message-Id: <1663120270-2673-1-git-send-email-jdamato@fastly.com> X-Mailer: git-send-email 2.7.4 ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1663120407; a=rsa-sha256; cv=none; b=orbliI821jm4LW+DUSicTsZdtwbuVUNRJAJ5cqHVd+K7lHEkwsPLKPg09nZMCAceqwKwUs QEczSzmaNfzAfAAYKUzBk0ePzFBGw7q+m9zTTQZSYNjeuZK9OFE/HaJ6l7Iw5Jv/pMtCns 4wc6s4OETOo9kcKSJCpuA9cJzz9uBAs= ARC-Authentication-Results: i=1; imf07.hostedemail.com; dkim=pass header.d=fastly.com header.s=google header.b=gfs2RGp7; dmarc=pass (policy=reject) header.from=fastly.com; spf=pass (imf07.hostedemail.com: domain of jdamato@fastly.com designates 209.85.216.53 as permitted sender) smtp.mailfrom=jdamato@fastly.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1663120407; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:references:dkim-signature; bh=TRgWwX2Tmd+EvHBnlkB6xTDwLdmxHLqUQDbVImjS7Xg=; b=3GgHdPExprwZ6408fjk4cXxoySEKCDFzxVmD0CFA0B+EJMJSh6IxmWeYKOepw6k0y3NRyA CJzVU5Ql41/LYXcbDPHfNtz+SvIz4jBgl1bYrAW0Rk/EPWPmv71RbGlUZSSazu3pwmVPJ1 koNYixWtAU0WSeWhnzRfJwqe5IRJljU= Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=fastly.com header.s=google header.b=gfs2RGp7; dmarc=pass (policy=reject) header.from=fastly.com; spf=pass (imf07.hostedemail.com: domain of jdamato@fastly.com designates 209.85.216.53 as permitted sender) smtp.mailfrom=jdamato@fastly.com X-Rspam-User: X-Rspamd-Server: rspam01 X-Stat-Signature: uh4rmusf7kjfh6inp6ntfig5qe49gsg1 X-Rspamd-Queue-Id: 36F1040090 X-HE-Tag: 1663120407-283318 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: Greetings: TLB shootdown events can be measured on a per-CPU basis by examining /proc/interrupts. Further information about TLB events can be harvested from /proc/vmstat if CONFIG_DEBUG_TLBFLUSH is enabled, but this information is system-wide. This information is useful, but on a busy system with many tasks it can be difficult to disambiguate the source of the TLB shootdown events. Having this information tracked per-task can enable developers to fix or tweak userland allocators to reduce the number of IPIs and improve application performance. This change adds two new fields to task_struct and signal_struct to help track TLB events: - ngtlbflush: number of tlb flushes generated - nrtlbflush: number of tlb flushes received These stats are exported in /proc/[pid]/stat alongside similar metrics (e.g. min_flt and maj_flt) for analysis. I've gotten code into kernel networking / drivers before, but I've never hacked on mm and mm-adjacent code before. Please let me know if there's a glaring issue and I'll be happy to tweak this code as necessary. If this seems OK, I'll send an official v1. Thanks! Joe Damato (1): mm: Add per-task struct tlb counters arch/x86/mm/tlb.c | 2 ++ fs/proc/array.c | 9 +++++++++ include/linux/sched.h | 6 ++++++ include/linux/sched/signal.h | 1 + kernel/exit.c | 6 ++++++ kernel/fork.c | 1 + 6 files changed, 25 insertions(+) -- 2.7.4