From: Matthew Wilcox <willy@infradead.org>
To: Amir Goldstein <amir73il@gmail.com>
Cc: Chris Down <chris@chrisdown.name>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Al Viro <viro@zeniv.linux.org.uk>,
Jeff Layton <jlayton@kernel.org>,
Johannes Weiner <hannes@cmpxchg.org>, Tejun Heo <tj@kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
kernel-team@fb.com, Hugh Dickins <hughd@google.com>,
Miklos Szeredi <miklos@szeredi.hu>,
"zhengbin (A)" <zhengbin13@huawei.com>
Subject: Re: [PATCH] fs: inode: Reduce volatile inode wraparound risk when ino_t is 64 bit
Date: Fri, 20 Dec 2019 08:46:32 -0800 [thread overview]
Message-ID: <20191220164632.GA26902@bombadil.infradead.org> (raw)
In-Reply-To: <CAOQ4uxgo_kAttnB4N1+om5gScYSDn3FXAr+_GUiqNy_79iiLXQ@mail.gmail.com>
On Fri, Dec 20, 2019 at 03:41:11PM +0200, Amir Goldstein wrote:
> Suggestion:
> 1. Extend the kmem_cache API to let the ctor() know if it is
> initializing an object
> for the first time (new page) or recycling an object.
Uh, what? The ctor is _only_ called when new pages are allocated.
Part of the contract with the slab user is that objects are returned to
the slab in an initialised state.
> 2. Let shmem_init_inode retain the value of i_ino of recycled shmem_inode_info
> objects
> 3. i_ino is initialized with get_next_ino() only in case it it zero
>
> Alternatively to 1., if simpler to implement and acceptable by slab developers:
> 1.b. remove the assertion from cache_grow_begin()/new_slab_objects():
> WARN_ON_ONCE(s->ctor && (flags & __GFP_ZERO));
> and pass __GFP_ZERO in shmem_alloc_inode()
WTF would that _mean_? I want this object to contain zeroes and whatever
the constructor sets it to. WHich one wins?
next prev parent reply other threads:[~2019-12-20 16:46 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-20 2:49 [PATCH] fs: inode: Reduce volatile inode wraparound risk when ino_t is 64 bit Chris Down
2019-12-20 3:05 ` zhengbin (A)
2019-12-20 8:32 ` Amir Goldstein
2019-12-20 12:16 ` Chris Down
2019-12-20 13:41 ` Amir Goldstein
2019-12-20 16:46 ` Matthew Wilcox [this message]
2019-12-20 17:35 ` Amir Goldstein
2019-12-20 19:50 ` Matthew Wilcox
2019-12-23 20:45 ` Chris Down
2019-12-24 3:04 ` Amir Goldstein
2019-12-25 12:54 ` Chris Down
2019-12-26 1:40 ` zhengbin (A)
2019-12-20 21:30 ` Darrick J. Wong
2019-12-21 8:43 ` Amir Goldstein
2019-12-21 18:05 ` Darrick J. Wong
2019-12-21 10:16 ` Chris Down
2020-01-07 17:35 ` J. Bruce Fields
2020-01-07 17:44 ` Chris Down
2020-01-08 3:00 ` J. Bruce Fields
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