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From: Greg Kurz <groug@kaod.org>
To: Dominique Martinet <asmadeus@codewreck.org>
Cc: Matthew Wilcox <willy@infradead.org>,
	Latchesar Ionkov <lucho@ionkov.net>,
	Eric Van Hensbergen <ericvh@gmail.com>,
	linux-kernel@vger.kernel.org, Ron Minnich <rminnich@sandia.gov>,
	linux-fsdevel@vger.kernel.org,
	v9fs-developer@lists.sourceforge.net
Subject: Re: [V9fs-developer] [PATCH v2 4/6] 9p: Embed wait_queue_head into p9_req_t
Date: Thu, 12 Jul 2018 16:59:14 +0200	[thread overview]
Message-ID: <20180712165914.7d1f949f@bahia.lan> (raw)
In-Reply-To: <20180712144012.GA21574@nautica>

On Thu, 12 Jul 2018 16:40:12 +0200
Dominique Martinet <asmadeus@codewreck.org> wrote:

> Greg Kurz wrote on Thu, Jul 12, 2018:
> > This is true when all tags have been used at least once. But the current code
> > lazily allocates the wait_queue_head_t, ie, only when a tag is used for the
> > first time. Your patch causes a full row of wait_quest_head_t to be pre-allocated.
> > 
> > ie, P9_ROW_MAXTAG * 24 = 255 * 24 = 6120
> > 
> > instead of (P9_ROW_MAXTAG * 8) + 24 = 255 * 8 + 24 = 2064
> > 
> > This is nearly a page of allocated memory that might be never used.
> > 
> > Not sure if this is a problem though...  
> 
> I thought the exact same, but the next patch in the serie removes that
> array and allocates even more lazily with a slab, so this was a
> no-brainer :)
> 

Ah ? I haven't started looking at that *big* other patch yet... :)

  reply	other threads:[~2018-07-12 15:16 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-11 21:02 [PATCH v2 0/6] 9p: Use IDRs more effectively Matthew Wilcox
2018-07-11 21:02 ` [PATCH v2 1/6] 9p: Fix comment on smp_wmb Matthew Wilcox
2018-07-12 11:55   ` [V9fs-developer] " Greg Kurz
2018-07-11 21:02 ` [PATCH v2 2/6] 9p: Change p9_fid_create calling convention Matthew Wilcox
2018-07-12  2:15   ` [V9fs-developer] " piaojun
2018-07-12 11:56   ` Greg Kurz
2018-07-13  1:18   ` jiangyiwen
2018-07-11 21:02 ` [PATCH v2 3/6] 9p: Replace the fidlist with an IDR Matthew Wilcox
2018-07-12 11:17   ` Dominique Martinet
2018-07-12 11:23     ` Matthew Wilcox
2018-07-12 11:30       ` Dominique Martinet
2018-07-13  2:05   ` [V9fs-developer] " jiangyiwen
2018-07-13  2:48     ` Matthew Wilcox
2018-07-11 21:02 ` [PATCH v2 4/6] 9p: Embed wait_queue_head into p9_req_t Matthew Wilcox
2018-07-12 14:36   ` [V9fs-developer] " Greg Kurz
2018-07-12 14:40     ` Dominique Martinet
2018-07-12 14:59       ` Greg Kurz [this message]
2018-07-11 21:02 ` [PATCH v2 5/6] 9p: Use a slab for allocating requests Matthew Wilcox
2018-07-18 10:05   ` Dominique Martinet
2018-07-18 11:49     ` Matthew Wilcox
2018-07-18 12:46       ` Dominique Martinet
2018-07-23 11:52     ` Greg Kurz
2018-07-23 12:25       ` Dominique Martinet
2018-07-23 14:24         ` Greg Kurz
2018-07-30  9:31         ` Dominique Martinet
2018-07-30  9:34           ` [PATCH 1/2] net/9p: embed fcall in req to round down buffer allocs Dominique Martinet
2018-07-30  9:34             ` [PATCH 2/2] net/9p: add a per-client fcall kmem_cache Dominique Martinet
2018-07-31  1:18               ` [V9fs-developer] " piaojun
2018-07-31  1:35                 ` Dominique Martinet
2018-07-31  1:45                   ` piaojun
2018-07-31  2:46               ` Matthew Wilcox
2018-07-31  4:17                 ` Dominique Martinet
2018-08-01 14:28               ` [V9fs-developer] " Greg Kurz
2018-08-01 15:22                 ` Dominique Martinet
2018-07-31  0:55             ` [V9fs-developer] [PATCH 1/2] net/9p: embed fcall in req to round down buffer allocs piaojun
2018-07-31  1:12               ` Dominique Martinet
2018-07-31  1:28                 ` piaojun
2018-08-01 14:14             ` Greg Kurz
2018-08-01 14:38               ` Dominique Martinet
2018-08-01 15:03                 ` Greg Kurz
2018-08-02  2:37             ` [PATCH v2 " Dominique Martinet
2018-08-02  2:37               ` [PATCH v2 2/2] net/9p: add a per-client fcall kmem_cache Dominique Martinet
2018-08-02  4:58                 ` [V9fs-developer] " Dominique Martinet
2018-08-02  9:23               ` [PATCH v2 1/2] net/9p: embed fcall in req to round down buffer allocs Greg Kurz
2018-08-02 22:03                 ` Dominique Martinet
2018-08-09 14:33               ` [PATCH v3 " Dominique Martinet
2018-08-09 14:33                 ` [PATCH v3 2/2] net/9p: add a per-client fcall kmem_cache Dominique Martinet
2018-08-10  1:23                   ` piaojun
2018-08-10  1:41                     ` Dominique Martinet
2018-08-10  1:49                       ` piaojun
2018-08-10  0:47                 ` [PATCH v3 1/2] net/9p: embed fcall in req to round down buffer allocs piaojun
2018-07-11 21:02 ` [PATCH v2 6/6] 9p: Remove p9_idpool Matthew Wilcox
2018-07-11 23:37 ` [PATCH v2 0/6] 9p: Use IDRs more effectively Dominique Martinet

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