linux-kernel - Re: [PATCH] mm: create a separate slab for page->ptl allocation

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20131022125512.GA24418@localhost>
Date:	Tue, 22 Oct 2013 13:55:12 +0100
From:	Fengguang Wu <fengguang.wu@...el.com>
To:	"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...hat.com>, linux-kernel@...r.kernel.org,
	linux-mm@...ck.org, linux-arch@...r.kernel.org
Subject: Re: [PATCH] mm: create a separate slab for page->ptl allocation

On Tue, Oct 22, 2013 at 02:53:59PM +0300, Kirill A. Shutemov wrote:
> If DEBUG_SPINLOCK and DEBUG_LOCK_ALLOC are enabled spinlock_t on x86_64
> is 72 bytes. For page->ptl they will be allocated from kmalloc-96 slab,
> so we loose 24 on each. An average system can easily allocate few tens
> thousands of page->ptl and overhead is significant.
> 
> Let's create a separate slab for page->ptl allocation to solve this.

Tested-by: Fengguang Wu <fengguang.wu@...el.com>

In a 4p server, we noticed up to +469.1% increase in will-it-scale page_fault3
test case and +199.8% in vm-scalability case-shm-pread-seq-mt.

    5c02216ce3110aab070d      5a58baaa0a1af0a43d7c
------------------------  ------------------------  
               300409.00      +440.2%   1622770.80  TOTAL will-it-scale.page_fault3.90.threads

    5c02216ce3110aab070d      5a58baaa0a1af0a43d7c
------------------------  ------------------------  
               291257.80      +469.1%   1657582.20  TOTAL will-it-scale.page_fault3.120.threads

...

    5c02216ce3110aab070d      5a58baaa0a1af0a43d7c
------------------------  ------------------------  
              4034831.40      +199.8%  12095649.80  TOTAL vm-scalability.throughput

Thanks,
Fengguang
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/