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Thu, 5 Aug 2021 15:20:08 +0000 (UTC) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 8820E223E3; Thu, 5 Aug 2021 15:20:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1628176807; 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=R8OF9oy48H16sGSYglqcUPzXTNP66A4yq3Yxy1FwsOU=; b=00bC+hQRHgzZSkTWTXEs56t0xtklqlRUEiemH/Dgc8LgtPwSqyhHBfA6QZ8zFjusUI+T08 YxGhnDKJ47AxleAA163qRTLl9CR9GhtqG5zsMsBtX4DzeGF65mQUn8chhvxXJE1RSXzEZR m+03KL3/a4pad3qGBLQcvY0XsHYRGrM= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1628176807; 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=R8OF9oy48H16sGSYglqcUPzXTNP66A4yq3Yxy1FwsOU=; b=XWQ4oGlLYkwiMepVoUqnPkh9rBN4sb20t8bM1tXp8SxRyR3C3g2IJg7207xJgggjjeveVI nCklxk5Y9hMAKkCg== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 59CA513DA8; Thu, 5 Aug 2021 15:20:07 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id ECAVFacBDGFDdQAAMHmgww (envelope-from ); Thu, 05 Aug 2021 15:20:07 +0000 From: Vlastimil Babka To: Andrew Morton , Christoph Lameter , David Rientjes , Pekka Enberg , Joonsoo Kim Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Mike Galbraith , Sebastian Andrzej Siewior , Thomas Gleixner , Mel Gorman , Jesper Dangaard Brouer , Jann Horn , Vlastimil Babka Subject: [PATCH v4 18/35] mm, slub: stop disabling irqs around get_partial() Date: Thu, 5 Aug 2021 17:19:43 +0200 Message-Id: <20210805152000.12817-19-vbabka@suse.cz> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210805152000.12817-1-vbabka@suse.cz> References: <20210805152000.12817-1-vbabka@suse.cz> MIME-Version: 1.0 Authentication-Results: imf29.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=00bC+hQR; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=XWQ4oGlL; dmarc=none; spf=pass (imf29.hostedemail.com: domain of vbabka@suse.cz designates 195.135.220.28 as permitted sender) smtp.mailfrom=vbabka@suse.cz X-Stat-Signature: 8ng1ff4nph59oebn86nyrm7npbbkotrc X-Rspamd-Queue-Id: 926B79002589 X-Rspamd-Server: rspam01 X-HE-Tag: 1628176808-176423 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: The function get_partial() does not need to have irqs disabled as a whole. It's sufficient to convert spin_lock operations to their irq saving/restoring versions. As a result, it's now possible to reach the page allocator from the slab allocator without disabling and re-enabling interrupts on the way. Signed-off-by: Vlastimil Babka --- mm/slub.c | 22 ++++++++-------------- 1 file changed, 8 insertions(+), 14 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index f7c6cebb524d..b4a62aa00ae2 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -1993,11 +1993,12 @@ static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags); * Try to allocate a partial slab from a specific node. */ static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n, - struct page **ret_page, gfp_t flags) + struct page **ret_page, gfp_t gfpflags) { struct page *page, *page2; void *object = NULL; unsigned int available = 0; + unsigned long flags; int objects; /* @@ -2009,11 +2010,11 @@ static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n, if (!n || !n->nr_partial) return NULL; - spin_lock(&n->list_lock); + spin_lock_irqsave(&n->list_lock, flags); list_for_each_entry_safe(page, page2, &n->partial, slab_list) { void *t; - if (!pfmemalloc_match(page, flags)) + if (!pfmemalloc_match(page, gfpflags)) continue; t = acquire_slab(s, n, page, object == NULL, &objects); @@ -2034,7 +2035,7 @@ static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n, break; } - spin_unlock(&n->list_lock); + spin_unlock_irqrestore(&n->list_lock, flags); return object; } @@ -2749,8 +2750,10 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, local_irq_restore(flags); goto reread_page; } - if (unlikely(!slub_percpu_partial(c))) + if (unlikely(!slub_percpu_partial(c))) { + local_irq_restore(flags); goto new_objects; /* stolen by an IRQ handler */ + } page = c->page = slub_percpu_partial(c); slub_set_percpu_partial(c, page); @@ -2759,18 +2762,9 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, goto redo; } - local_irq_save(flags); - if (unlikely(c->page)) { - local_irq_restore(flags); - goto reread_page; - } - new_objects: - lockdep_assert_irqs_disabled(); - freelist = get_partial(s, gfpflags, node, &page); - local_irq_restore(flags); if (freelist) goto check_new_page;