From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id B9796C761A6 for ; Thu, 30 Mar 2023 11:56:44 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 54565900002; Thu, 30 Mar 2023 07:56:44 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4F6136B0074; Thu, 30 Mar 2023 07:56:44 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 39659900002; Thu, 30 Mar 2023 07:56:44 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 2A6FF6B0072 for ; Thu, 30 Mar 2023 07:56:44 -0400 (EDT) Received: from smtpin14.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id E56661A08AA for ; Thu, 30 Mar 2023 11:56:43 +0000 (UTC) X-FDA: 80625412686.14.4461E4E Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) by imf02.hostedemail.com (Postfix) with ESMTP id 664B680020 for ; Thu, 30 Mar 2023 11:56:39 +0000 (UTC) Authentication-Results: imf02.hostedemail.com; dkim=pass header.d=infradead.org header.s=desiato.20200630 header.b=bKGHblLx; spf=none (imf02.hostedemail.com: domain of peterz@infradead.org has no SPF policy when checking 90.155.92.199) smtp.mailfrom=peterz@infradead.org; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1680177401; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=k7uaT+sMnmeDWcjQU/N6p9lwO5v20LsnKAG8porccmM=; b=EFdilCwqhQtX0eXgvvAe/p8q90lWcuZkdXqKE8lyfbHixU5v67gMQGw7O4JSCKVMAnk6Oz wmTjMG+f8er0xaEGCsRYrpBGF0sES1ZNGhI8XV46aCdeK0X0BnZiHROPD8cWoUm+LU5sB7 5n5uzZRSeNL16AmOimQn/J/6wg3ELM0= ARC-Authentication-Results: i=1; imf02.hostedemail.com; dkim=pass header.d=infradead.org header.s=desiato.20200630 header.b=bKGHblLx; spf=none (imf02.hostedemail.com: domain of peterz@infradead.org has no SPF policy when checking 90.155.92.199) smtp.mailfrom=peterz@infradead.org; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1680177401; a=rsa-sha256; cv=none; b=25Sdm46toJBIXkt7mbxfsD1lj4QPoJ3ErdTOxtY867h/qIPSpB8cgbapd8wJb9kfvzQkvY Iipr5+EvpGe7G8rpSW0p2w69sSVPTEGlHVD8NhowiXPXeQ9mOfcrVCjAYyXjU6MpbLGyMm HMJM5uYDOtPoSR+egDKgHZmNlS9+I9A= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=k7uaT+sMnmeDWcjQU/N6p9lwO5v20LsnKAG8porccmM=; b=bKGHblLxGK5HyB9nqT1iZNN8IZ Jwito8ISCxvONnPiJog41gh0/xiv7+Jr9a+RNjRX4fIvDUXNpAMXuDzjdxZiPH2bE/T4GiOyJZuEz uPstI2+e99KjsP8XnUsWohuERcczDzOwwKt85tANyMCCTzf4P2WcXR5K5Kc5SDj/xuXwWlqDKKQDl WxkhhKhMVFQUzSOY5HgmDQdmi03mOHGJHcMvCRQqUgbgVlC9s87CMizLxdEwF5NCmvCCN0zsFn08W DwR9NDzy3fkGdpNS93mHwCzMZNuQr0v1MoLUc2UAjnU3AGEUlmie7i/MhPkLNAXcK+XHxw2ux0G2k Vdeh4uuQ==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1phqtJ-007B4v-2x; Thu, 30 Mar 2023 11:56:30 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id AD71E3002A3; Thu, 30 Mar 2023 13:56:26 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 5B9402421D7A0; Thu, 30 Mar 2023 13:56:26 +0200 (CEST) Date: Thu, 30 Mar 2023 13:56:26 +0200 From: Peter Zijlstra To: Linus Torvalds Cc: Luis Chamberlain , david@redhat.com, patches@lists.linux.dev, linux-modules@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, pmladek@suse.com, petr.pavlu@suse.com, prarit@redhat.com, gregkh@linuxfoundation.org, rafael@kernel.org, christophe.leroy@csgroup.eu, tglx@linutronix.de, song@kernel.org, rppt@kernel.org, willy@infradead.org, vbabka@suse.cz, mhocko@suse.com, dave.hansen@linux.intel.com Subject: Re: [PATCH 4/7] sempahore: add a helper for a concurrency limiter Message-ID: <20230330115626.GA124812@hirez.programming.kicks-ass.net> References: <20230329053149.3976378-1-mcgrof@kernel.org> <20230329053149.3976378-5-mcgrof@kernel.org> <20230329072112.GG4253@hirez.programming.kicks-ass.net> <20230329091935.GP4253@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Server: rspam03 X-Stat-Signature: 76fs9ycja4ieuectgnd1rk1chrgxs639 X-Rspamd-Queue-Id: 664B680020 X-HE-Tag: 1680177399-67833 X-HE-Meta: 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 PeyAlzfp 2AtXOgtgSTGkUQvACq2lPJwlTEfaThFBXuAtLbmq4ESnkZRLwZ3waqN0LYcjoSMs6KNiSRSGEce4xPfOC9bv5ltffVWT80eSY7gs8W0BnwbxH9h7U8QY7qZfzsusch23utzKU4iS4o1YY5DGCSAO+uTD0htQk8k6Fq0uFlZRIFinupwz4SNTlzs3gl/KXHnYfRlS9tTDd5MB/XfbpctU2qeIv3Q== 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: On Wed, Mar 29, 2023 at 09:50:39AM -0700, Linus Torvalds wrote: > So ack on your patch, but don't bother with DEFINE_BINARY_SEMAPHORE(). Sure thing; still completely untested... --- Subject: Change DEFINE_SEMAPHORE() to take a number argument From: Peter Zijlstra Date: Wed, 29 Mar 2023 12:14:42 +0200 Fundamentally semaphores are a counted primitive, but DEFINE_SEMAPHORE() does not expose this and explicitly creates a binary semaphore. Change DEFINE_SEMAPHORE() to take a number argument and use that in the few places that open-coded it using __SEMAPHORE_INITIALIZER(). Signed-off-by: Peter Zijlstra (Intel) --- arch/mips/cavium-octeon/setup.c | 2 +- arch/x86/kernel/cpu/intel.c | 2 +- drivers/firmware/efi/runtime-wrappers.c | 2 +- drivers/firmware/efi/vars.c | 2 +- drivers/macintosh/adb.c | 2 +- drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c | 2 +- drivers/platform/x86/intel/ifs/sysfs.c | 2 +- drivers/scsi/esas2r/esas2r_ioctl.c | 2 +- drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c | 2 +- include/linux/semaphore.h | 4 ++-- kernel/printk/printk.c | 2 +- net/rxrpc/call_object.c | 6 ++---- 12 files changed, 14 insertions(+), 16 deletions(-) --- a/arch/mips/cavium-octeon/setup.c +++ b/arch/mips/cavium-octeon/setup.c @@ -72,7 +72,7 @@ extern void pci_console_init(const char static unsigned long long max_memory = ULLONG_MAX; static unsigned long long reserve_low_mem; -DEFINE_SEMAPHORE(octeon_bootbus_sem); +DEFINE_SEMAPHORE(octeon_bootbus_sem, 1); EXPORT_SYMBOL(octeon_bootbus_sem); static struct octeon_boot_descriptor *octeon_boot_desc_ptr; --- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -1177,7 +1177,7 @@ static const struct { static struct ratelimit_state bld_ratelimit; static unsigned int sysctl_sld_mitigate = 1; -static DEFINE_SEMAPHORE(buslock_sem); +static DEFINE_SEMAPHORE(buslock_sem, 1); #ifdef CONFIG_PROC_SYSCTL static struct ctl_table sld_sysctls[] = { --- a/drivers/firmware/efi/runtime-wrappers.c +++ b/drivers/firmware/efi/runtime-wrappers.c @@ -158,7 +158,7 @@ void efi_call_virt_check_flags(unsigned * none of the remaining functions are actually ever called at runtime. * So let's just use a single lock to serialize all Runtime Services calls. */ -static DEFINE_SEMAPHORE(efi_runtime_lock); +static DEFINE_SEMAPHORE(efi_runtime_lock, 1); /* * Expose the EFI runtime lock to the UV platform --- a/drivers/firmware/efi/vars.c +++ b/drivers/firmware/efi/vars.c @@ -21,7 +21,7 @@ /* Private pointer to registered efivars */ static struct efivars *__efivars; -static DEFINE_SEMAPHORE(efivars_lock); +static DEFINE_SEMAPHORE(efivars_lock, 1); static efi_status_t check_var_size(bool nonblocking, u32 attributes, unsigned long size) --- a/drivers/macintosh/adb.c +++ b/drivers/macintosh/adb.c @@ -80,7 +80,7 @@ static struct adb_driver *adb_controller BLOCKING_NOTIFIER_HEAD(adb_client_list); static int adb_got_sleep; static int adb_inited; -static DEFINE_SEMAPHORE(adb_probe_mutex); +static DEFINE_SEMAPHORE(adb_probe_mutex, 1); static int sleepy_trackpad; static int autopoll_devs; int __adb_probe_sync; --- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c +++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c @@ -298,7 +298,7 @@ const u32 dmae_reg_go_c[] = { /* Global resources for unloading a previously loaded device */ #define BNX2X_PREV_WAIT_NEEDED 1 -static DEFINE_SEMAPHORE(bnx2x_prev_sem); +static DEFINE_SEMAPHORE(bnx2x_prev_sem, 1); static LIST_HEAD(bnx2x_prev_list); /* Forward declaration */ --- a/drivers/platform/x86/intel/ifs/sysfs.c +++ b/drivers/platform/x86/intel/ifs/sysfs.c @@ -13,7 +13,7 @@ * Protects against simultaneous tests on multiple cores, or * reloading can file while a test is in progress */ -static DEFINE_SEMAPHORE(ifs_sem); +static DEFINE_SEMAPHORE(ifs_sem, 1); /* * The sysfs interface to check additional details of last test --- a/drivers/scsi/esas2r/esas2r_ioctl.c +++ b/drivers/scsi/esas2r/esas2r_ioctl.c @@ -56,7 +56,7 @@ dma_addr_t esas2r_buffered_ioctl_addr; u32 esas2r_buffered_ioctl_size; struct pci_dev *esas2r_buffered_ioctl_pcid; -static DEFINE_SEMAPHORE(buffered_ioctl_semaphore); +static DEFINE_SEMAPHORE(buffered_ioctl_semaphore, 1); typedef int (*BUFFERED_IOCTL_CALLBACK)(struct esas2r_adapter *, struct esas2r_request *, struct esas2r_sg_context *, --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c @@ -149,7 +149,7 @@ static char *g_fragments_base; static char *g_free_fragments; static struct semaphore g_free_fragments_sema; -static DEFINE_SEMAPHORE(g_free_fragments_mutex); +static DEFINE_SEMAPHORE(g_free_fragments_mutex, 1); static int vchiq_blocking_bulk_transfer(struct vchiq_instance *instance, unsigned int handle, void *data, --- a/include/linux/semaphore.h +++ b/include/linux/semaphore.h @@ -25,8 +25,8 @@ struct semaphore { .wait_list = LIST_HEAD_INIT((name).wait_list), \ } -#define DEFINE_SEMAPHORE(name) \ - struct semaphore name = __SEMAPHORE_INITIALIZER(name, 1) +#define DEFINE_SEMAPHORE(_name, _n) \ + struct semaphore _name = __SEMAPHORE_INITIALIZER(_name, _n) static inline void sema_init(struct semaphore *sem, int val) { --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -89,7 +89,7 @@ static DEFINE_MUTEX(console_mutex); * console_sem protects updates to console->seq and console_suspended, * and also provides serialization for console printing. */ -static DEFINE_SEMAPHORE(console_sem); +static DEFINE_SEMAPHORE(console_sem, 1); HLIST_HEAD(console_list); EXPORT_SYMBOL_GPL(console_list); DEFINE_STATIC_SRCU(console_srcu); --- a/net/rxrpc/call_object.c +++ b/net/rxrpc/call_object.c @@ -40,10 +40,8 @@ const char *const rxrpc_call_completions struct kmem_cache *rxrpc_call_jar; -static struct semaphore rxrpc_call_limiter = - __SEMAPHORE_INITIALIZER(rxrpc_call_limiter, 1000); -static struct semaphore rxrpc_kernel_call_limiter = - __SEMAPHORE_INITIALIZER(rxrpc_kernel_call_limiter, 1000); +static DEFINE_SEMAPHORE(rxrpc_call_limiter, 1000); +static DEFINE_SEMAPHORE(rxrpc_kernel_call_limiter, 1000); void rxrpc_poke_call(struct rxrpc_call *call, enum rxrpc_call_poke_trace what) {