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[94.245.46.49]) by smtp.gmail.com with ESMTPSA id n4sm135298lfl.40.2020.06.18.11.23.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 18 Jun 2020 11:23:35 -0700 (PDT) From: Uladzislau Rezki X-Google-Original-From: Uladzislau Rezki Date: Thu, 18 Jun 2020 20:23:33 +0200 To: Matthew Wilcox Cc: Uladzislau Rezki , "Paul E. McKenney" , LKML , linux-mm@kvack.org, Andrew Morton , "Theodore Y . Ts'o" , Joel Fernandes , RCU , Oleksiy Avramchenko Subject: Re: [PATCH v2 09/16] rcu/tree: Maintain separate array for vmalloc ptrs Message-ID: <20200618182333.GA15082@pc636> References: <20200525214800.93072-1-urezki@gmail.com> <20200525214800.93072-10-urezki@gmail.com> <20200617234609.GA10087@paulmck-ThinkPad-P72> <20200618172504.GA14613@pc636> <20200618173206.GS2723@paulmck-ThinkPad-P72> <20200618175623.GA14865@pc636> <20200618181541.GS8681@bombadil.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200618181541.GS8681@bombadil.infradead.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: rcu-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org On Thu, Jun 18, 2020 at 11:15:41AM -0700, Matthew Wilcox wrote: > On Thu, Jun 18, 2020 at 07:56:23PM +0200, Uladzislau Rezki wrote: > > If we mix pointers, then we can do free per pointer only. I mean in that > > case we will not be able to use kfree_bulk() interface for freeing SLAB > > memory and the code would converted to something like: > > > > > > while (nr_objects_in_array > 0) { > > if (is_vmalloc_addr(array[X])) > > vfree(array[X]); > > else > > kfree(array[X]); > > } > > > > [PATCH] Add vfree_bulk interface > > This is a useful interface to have for the RCU kvfree code. There is > scope for more performance gains later, but introducing the interface > now allows us to simplify the RCU code today. > > Signed-off-by: Matthew Wilcox (Oracle) > > diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h > index 48bb681e6c2a..dc2bbb61af61 100644 > --- a/include/linux/vmalloc.h > +++ b/include/linux/vmalloc.h > @@ -119,6 +119,7 @@ void *__vmalloc_node(unsigned long size, unsigned long align, gfp_t gfp_mask, > > extern void vfree(const void *addr); > extern void vfree_atomic(const void *addr); > +extern void vfree_bulk(size_t count, void **addrs); > > extern void *vmap(struct page **pages, unsigned int count, > unsigned long flags, pgprot_t prot); > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index abe37f09ac42..6042f9b4394a 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -2366,6 +2366,22 @@ void vfree(const void *addr) > } > EXPORT_SYMBOL(vfree); > > +void vfree_bulk(size_t count, void **addrs) > +{ > + unsigned int i; > + > + BUG_ON(in_nmi()); > + might_sleep_if(!in_interrupt()); > + > + for (i = 0; i < count; i++) { > + void *addr = addrs[i]; > + kmemleak_free(addr); > + if (addr) > + __vfree(addr); > + } > +} > +EXPORT_SYMBOL(vfree_bulk); > + > Can we just do addrs[i] all over the loop? Also, we can just call vfree() instead that has all checking we need: NMI, kmemleak, might_sleep. Thanks! -- Vlad Rezki