From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Ganesh Mahendran <opensource.ganesh@gmail.com>,
Minchan Kim <minchan@kernel.org>, Nitin Gupta <ngupta@vflare.org>,
Andrew Morton <akpm@linux-foundation.org>,
Linux-MM <linux-mm@kvack.org>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm/zsmalloc: avoid unnecessary iteration in get_pages_per_zspage()
Date: Fri, 6 May 2016 18:33:42 +0900 [thread overview]
Message-ID: <20160506093342.GB488@swordfish> (raw)
In-Reply-To: <20160506090801.GA488@swordfish>
On (05/06/16 18:08), Sergey Senozhatsky wrote:
[..]
> and it's not 45 iterations that we are getting rid of, but around 31:
> not every class reaches it's ideal 100% ratio on the first iteration.
> so, no, sorry, I don't think the patch really does what we want.
to be clear, what I meant was:
495 `cmp' + 15 `cmp je' IN
31 `mov cltd idiv mov sub imul cltd idiv cmp' OUT
IN > OUT.
CORRECTION here:
> * by the way, we don't even need `cltd' in those calculations. the
> reason why gcc puts cltd is because ZS_MAX_PAGES_PER_ZSPAGE has the
> 'wrong' data type. the patch to correct it is below (not a formal
> patch).
no, we need cltd there. but ZS_MAX_PAGES_PER_ZSPAGE also affects
ZS_MIN_ALLOC_SIZE, which is used in several places, like
get_size_class_index(). that's why ZS_MAX_PAGES_PER_ZSPAGE data
type change `improves' zs_malloc().
-ss
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next prev parent reply other threads:[~2016-05-06 9:32 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-05 5:17 [PATCH] mm/zsmalloc: avoid unnecessary iteration in get_pages_per_zspage() Ganesh Mahendran
2016-05-05 10:03 ` Sergey Senozhatsky
2016-05-06 3:09 ` Minchan Kim
2016-05-06 4:25 ` Ganesh Mahendran
2016-05-06 4:37 ` Minchan Kim
2016-05-06 9:08 ` Sergey Senozhatsky
2016-05-06 9:33 ` Sergey Senozhatsky [this message]
2016-05-09 5:01 ` Minchan Kim
2016-05-11 9:34 ` Sergey Senozhatsky
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