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Wed, 27 Mar 2024 15:23:05 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap2.dmz-prg2.suse.org with ESMTPSA id qHk9L9k5BGZafgAAn2gu4w (envelope-from ); Wed, 27 Mar 2024 15:23:05 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: e9177cc7-ec4d-11ee-afe3-a90da7624cb6 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1711552986; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=BqLZjhhBHT3mnXz0DltiWo9mb+SXQAswcBtFsIHNjqU=; b=eCXUM4ctFmRMh/J+LAGK+4e1y6KxkqEmjC1ysplW7YQaysPSYjXGtyhqKUD1gvSekLojS1 0OBAg7wu6A+GkGTa26PDu6zJer/uDcsAX2adBHRNJGOXA1RrDK6pZ16WetQp//PapgewKy 0O83/8aW6LWvhU/Wi0CV0c7dPXKkSJc= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1711552986; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=BqLZjhhBHT3mnXz0DltiWo9mb+SXQAswcBtFsIHNjqU=; b=eCXUM4ctFmRMh/J+LAGK+4e1y6KxkqEmjC1ysplW7YQaysPSYjXGtyhqKUD1gvSekLojS1 0OBAg7wu6A+GkGTa26PDu6zJer/uDcsAX2adBHRNJGOXA1RrDK6pZ16WetQp//PapgewKy 0O83/8aW6LWvhU/Wi0CV0c7dPXKkSJc= From: Juergen Gross To: xen-devel@lists.xenproject.org Cc: Juergen Gross , Andrew Cooper , George Dunlap , Jan Beulich , Julien Grall , Stefano Stabellini Subject: [PATCH v6 6/8] xen/spinlock: support higher number of cpus Date: Wed, 27 Mar 2024 16:22:27 +0100 Message-Id: <20240327152229.25847-7-jgross@suse.com> X-Mailer: git-send-email 2.35.3 In-Reply-To: <20240327152229.25847-1-jgross@suse.com> References: <20240327152229.25847-1-jgross@suse.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Spam-Score: 3.70 X-Spamd-Result: default: False [3.70 / 50.00]; RCVD_VIA_SMTP_AUTH(0.00)[]; TO_DN_SOME(0.00)[]; R_MISSING_CHARSET(2.50)[]; BROKEN_CONTENT_TYPE(1.50)[]; RCVD_COUNT_THREE(0.00)[3]; NEURAL_HAM_SHORT(-0.20)[-1.000]; RCPT_COUNT_SEVEN(0.00)[7]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; ARC_NA(0.00)[]; FROM_HAS_DN(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; MIME_GOOD(-0.10)[text/plain]; DKIM_SIGNED(0.00)[suse.com:s=susede1]; MID_CONTAINS_FROM(1.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.com:email]; FUZZY_BLOCKED(0.00)[rspamd.com]; RCVD_TLS_ALL(0.00)[] X-Spam-Level: *** Authentication-Results: smtp-out2.suse.de; none X-Spam-Flag: NO X-ZohoMail-DKIM: pass (identity @suse.com) X-ZM-MESSAGEID: 1711553001971100003 Content-Type: text/plain; charset="utf-8" Allow 16 bits per cpu number, which is the limit imposed by spinlock_tickets_t. This will allow up to 65535 cpus, while increasing only the size of recursive spinlocks in debug builds from 8 to 12 bytes. The current Xen limit of 4095 cpus is imposed by SPINLOCK_CPU_BITS being 12. There are machines available with more cpus than the current Xen limit, so it makes sense to have the possibility to use more cpus. Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich --- V5: - keep previous recursion limit (Julien Grall) V6: - use unsigned int instead of uint32_t (Jan Beulich) --- xen/common/spinlock.c | 2 ++ xen/include/xen/spinlock.h | 20 ++++++++++---------- 2 files changed, 12 insertions(+), 10 deletions(-) diff --git a/xen/common/spinlock.c b/xen/common/spinlock.c index 7ccb725171..5aa9ba6188 100644 --- a/xen/common/spinlock.c +++ b/xen/common/spinlock.c @@ -485,7 +485,9 @@ bool _rspin_trylock(rspinlock_t *lock) =20 /* Don't allow overflow of recurse_cpu field. */ BUILD_BUG_ON(NR_CPUS > SPINLOCK_NO_CPU); + BUILD_BUG_ON(SPINLOCK_CPU_BITS > sizeof(lock->recurse_cpu) * 8); BUILD_BUG_ON(SPINLOCK_RECURSE_BITS < 3); + BUILD_BUG_ON(SPINLOCK_MAX_RECURSE > ((1u << SPINLOCK_RECURSE_BITS) - 1= )); =20 check_lock(&lock->debug, true); =20 diff --git a/xen/include/xen/spinlock.h b/xen/include/xen/spinlock.h index 3a4092626c..db00a24646 100644 --- a/xen/include/xen/spinlock.h +++ b/xen/include/xen/spinlock.h @@ -8,16 +8,16 @@ #include #include =20 -#define SPINLOCK_CPU_BITS 12 +#define SPINLOCK_CPU_BITS 16 =20 #ifdef CONFIG_DEBUG_LOCKS union lock_debug { - uint16_t val; -#define LOCK_DEBUG_INITVAL 0xffff + uint32_t val; +#define LOCK_DEBUG_INITVAL 0xffffffff struct { - uint16_t cpu:SPINLOCK_CPU_BITS; -#define LOCK_DEBUG_PAD_BITS (14 - SPINLOCK_CPU_BITS) - uint16_t :LOCK_DEBUG_PAD_BITS; + unsigned int cpu:SPINLOCK_CPU_BITS; +#define LOCK_DEBUG_PAD_BITS (30 - SPINLOCK_CPU_BITS) + unsigned int :LOCK_DEBUG_PAD_BITS; bool irq_safe:1; bool unseen:1; }; @@ -211,11 +211,11 @@ typedef struct spinlock { =20 typedef struct rspinlock { spinlock_tickets_t tickets; - uint16_t recurse_cpu:SPINLOCK_CPU_BITS; + uint16_t recurse_cpu; #define SPINLOCK_NO_CPU ((1u << SPINLOCK_CPU_BITS) - 1) -#define SPINLOCK_RECURSE_BITS (16 - SPINLOCK_CPU_BITS) - uint16_t recurse_cnt:SPINLOCK_RECURSE_BITS; -#define SPINLOCK_MAX_RECURSE ((1u << SPINLOCK_RECURSE_BITS) - 1) +#define SPINLOCK_RECURSE_BITS 8 + uint8_t recurse_cnt; +#define SPINLOCK_MAX_RECURSE 15 union lock_debug debug; #ifdef CONFIG_DEBUG_LOCK_PROFILE struct lock_profile *profile; --=20 2.35.3