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bh=z8v4ryVEKUVoC+Nx8Pww9inYHYBKUn8XDFXC2DN/iVs=; b=PaMxdXxvO6Exmk8d3FptcxglUOrdFSfEbkRN4Jnc8ppEBjJ3TDmap479lfL7G7XqP/mIJL 0Ri6gSjT6zL40BCg== Received: from director2.suse.de ([192.168.254.72]) by imap3-int with ESMTPSA id iHkcN3aowGD6XgAALh3uQQ (envelope-from ); Wed, 09 Jun 2021 11:39:34 +0000 From: Vlastimil Babka To: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Christoph Lameter , David Rientjes , Pekka Enberg , Joonsoo Kim Cc: Sebastian Andrzej Siewior , Thomas Gleixner , Mel Gorman , Jesper Dangaard Brouer , Peter Zijlstra , Jann Horn , Vlastimil Babka Subject: [RFC v2 18/34] mm, slub: stop disabling irqs around get_partial() Date: Wed, 9 Jun 2021 13:38:47 +0200 Message-Id: <20210609113903.1421-19-vbabka@suse.cz> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210609113903.1421-1-vbabka@suse.cz> References: <20210609113903.1421-1-vbabka@suse.cz> MIME-Version: 1.0 Authentication-Results: imf22.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=hQJ14+UF; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=PaMxdXxv; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=hQJ14+UF; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=PaMxdXxv; dmarc=none; spf=pass (imf22.hostedemail.com: domain of vbabka@suse.cz designates 195.135.220.28 as permitted sender) smtp.mailfrom=vbabka@suse.cz X-Rspamd-Server: rspam02 X-Stat-Signature: mj19d39ro77ntaqiw4zdt8runizxaxa8 X-Rspamd-Queue-Id: BD25FC005A20 X-HE-Tag: 1623238771-384826 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 760080b58957..6f894d1e84d6 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -1950,11 +1950,12 @@ 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; /* @@ -1966,11 +1967,11 @@ 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); @@ -1991,7 +1992,7 @@ 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; } @@ -2706,8 +2707,10 @@ 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); @@ -2716,18 +2719,9 @@ 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;