From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 43AE81AAE23; Mon, 14 Oct 2024 11:00:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728903618; cv=none; b=QpoW2JZzYhWeP8o9FQtCCw3Cm8CzVfZ/zynlIhe3NB3p7kilD8LW5oDdCohZtYbdtDVycNfq7iRKO994/UK0cANFludtHdSCpkn+rGSuvnXNcvd7Fbrbq0RPzUOnw0xaif0pPSVb+slAmYwRVFLc7Pe3X4s8DKPzu4DIvQMr4cg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728903618; c=relaxed/simple; bh=ckI1+T2GFgSWcVYnvAcaN2k41SpN9b7TGriYQVjzmWI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=i9BM+aPJgJLWkBWmbx23IgDHdKZj/bRCqaYC/L/R5mVTF1WAj5+IRcD6LV7IRqB0D1Q5O9a4f16PIUJPswIQ77CntslSrzWMmdplzeeJ1U8RRuPGSkyvDQEjp2MuH9w8CpqPaUxcBrEiLzID+OZneHlhF1aMHgPEbVcMv8R64/k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 89DBA168F; Mon, 14 Oct 2024 04:00:46 -0700 (PDT) Received: from e125769.cambridge.arm.com (e125769.cambridge.arm.com [10.1.196.27]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 6B5403F51B; Mon, 14 Oct 2024 04:00:14 -0700 (PDT) From: Ryan Roberts To: Andrew Morton , Anshuman Khandual , Ard Biesheuvel , Catalin Marinas , David Hildenbrand , Greg Marsden , Ivan Ivanov , Kalesh Singh , Marc Zyngier , Mark Rutland , Matthias Brugger , Miroslav Benes , Will Deacon Cc: Ryan Roberts , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-perf-users@vger.kernel.org Subject: [RFC PATCH v1 16/57] perf: Remove PAGE_SIZE compile-time constant assumption Date: Mon, 14 Oct 2024 11:58:23 +0100 Message-ID: <20241014105912.3207374-16-ryan.roberts@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20241014105912.3207374-1-ryan.roberts@arm.com> References: <20241014105514.3206191-1-ryan.roberts@arm.com> <20241014105912.3207374-1-ryan.roberts@arm.com> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit To prepare for supporting boot-time page size selection, refactor code to remove assumptions about PAGE_SIZE being compile-time constant. Code intended to be equivalent when compile-time page size is active. Refactor a BUILD_BUG_ON() so that we test against the limit; _format is invariant to page size so testing it is no bigger than the minimum supported size is sufficient. Wrap global variables that are initialized with PAGE_SIZE derived values using DEFINE_GLOBAL_PAGE_SIZE_VAR() so their initialization can be deferred for boot-time page size builds. Signed-off-by: Ryan Roberts --- ***NOTE*** Any confused maintainers may want to read the cover note here for context: https://lore.kernel.org/all/20241014105514.3206191-1-ryan.roberts@arm.com/ include/linux/perf_event.h | 2 +- kernel/events/core.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 1a8942277ddad..b7972155f93eb 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -1872,7 +1872,7 @@ _name##_show(struct device *dev, \ struct device_attribute *attr, \ char *page) \ { \ - BUILD_BUG_ON(sizeof(_format) >= PAGE_SIZE); \ + BUILD_BUG_ON(sizeof(_format) >= PAGE_SIZE_MIN); \ return sprintf(page, _format "\n"); \ } \ diff --git a/kernel/events/core.c b/kernel/events/core.c index 8a6c6bbcd658a..81149663ab7d8 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -419,7 +419,7 @@ static struct kmem_cache *perf_event_cache; int sysctl_perf_event_paranoid __read_mostly = 2; /* Minimum for 512 kiB + 1 user control page */ -int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */ +__DEFINE_GLOBAL_PAGE_SIZE_VAR(int, sysctl_perf_event_mlock, __read_mostly, 512 + (PAGE_SIZE / 1024)); /* 'free' kiB per user */ /* * max perf event sample rate -- 2.43.0