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From:   Mateusz Guzik <mjguzik@gmail.com>
Date:   Thu, 2 Mar 2023 19:51:55 +0100
Message-ID: <CAGudoHFUkchB93rvOSFgBxkLJWT59hyGs==uTcvtO3pKyekxvQ@mail.gmail.com>
Subject: Re: [PATCH v3 2/2] vfs: avoid duplicating creds in faccessat if possible
To:     Al Viro <viro@zeniv.linux.org.uk>
Cc:     Linus Torvalds <torvalds@linux-foundation.org>,
        Christian Brauner <brauner@kernel.org>, serge@hallyn.com,
        paul@paul-moore.com, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org
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On 3/2/23, Al Viro <viro@zeniv.linux.org.uk> wrote:
> On Thu, Mar 02, 2023 at 07:22:17PM +0100, Mateusz Guzik wrote:
>
>> Ops, I meant "names_cache", here:
>> 	names_cachep = kmem_cache_create_usercopy("names_cache", PATH_MAX, 0,
>> 			SLAB_HWCACHE_ALIGN|SLAB_PANIC, 0, PATH_MAX, NULL);
>>
>> it is fs/dcache.c and I brainfarted into the above.
>
> So you mean __getname() stuff?
>

yes. do some lookups in a loop on a kernel built with
CONFIG_INIT_ON_ALLOC_DEFAULT_ON=y (there may be a runtime switch for
it?) and  you will see memset using most time in perf top

-- 
Mateusz Guzik <mjguzik gmail.com>