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From: Andrew Morton <akpm@linux-foundation.org>
To: Uladzislau Rezki <urezki@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
	Daniel Wagner <dwagner@suse.de>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	Thomas Gleixner <tglx@linutronix.de>,
	linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Hillf Danton <hdanton@sina.com>, Michal Hocko <mhocko@suse.com>,
	Matthew Wilcox <willy@infradead.org>,
	Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com>
Subject: Re: [PATCH 1/1] mm/vmalloc: remove preempt_disable/enable when do preloading
Date: Fri, 11 Oct 2019 16:55:15 -0700	[thread overview]
Message-ID: <20191011165515.a25e7d1c22e6b5e3e6fb69da@linux-foundation.org> (raw)
In-Reply-To: <20191010151749.GA14740@pc636>

On Thu, 10 Oct 2019 17:17:49 +0200 Uladzislau Rezki <urezki@gmail.com> wrote:

> > > : 	 * The preload is done in non-atomic context, thus it allows us
> > > : 	 * to use more permissive allocation masks to be more stable under
> > > : 	 * low memory condition and high memory pressure.
> > > : 	 *
> > > : 	 * Even if it fails we do not really care about that. Just proceed
> > > : 	 * as it is. "overflow" path will refill the cache we allocate from.
> > > : 	 */
> > > : 	if (!this_cpu_read(ne_fit_preload_node)) {
> > > 
> > > Readability nit: local `pva' should be defined here, rather than having
> > > function-wide scope.
> > > 
> > > : 		pva = kmem_cache_alloc_node(vmap_area_cachep, GFP_KERNEL, node);
> > > 
> > > Why doesn't this honour gfp_mask?  If it's not a bug, please add
> > > comment explaining this.
> > > 
> But there is a comment, if understand you correctly:
> 
> <snip>
> * Even if it fails we do not really care about that. Just proceed
> * as it is. "overflow" path will refill the cache we allocate from.
> <snip>

My point is that the alloc_vmap_area() caller passed us a gfp_t but
this code ignores it, as does adjust_va_to_fit_type().  These *look*
like potential bugs.  If not, they should be commented so they don't
look like bugs any more ;)




  reply	other threads:[~2019-10-11 23:55 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-09 16:49 [PATCH 1/1] mm/vmalloc: remove preempt_disable/enable when do preloading Uladzislau Rezki (Sony)
2019-10-09 18:21 ` Steven Rostedt
2019-10-09 22:19 ` Andrew Morton
2019-10-10  2:17   ` Steven Rostedt
2019-10-10 15:17     ` Uladzislau Rezki
2019-10-11 23:55       ` Andrew Morton [this message]
2019-10-14 14:27         ` Uladzislau Rezki
2019-10-14 16:30           ` Michal Hocko
2019-10-15  9:54             ` Uladzislau Rezki

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