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Message-ID: <5230C5A7.2030206@redhat.com> Date: Wed, 11 Sep 2013 14:33:59 -0500 From: Eric Sandeen <sandeen@...hat.com> To: "Theodore Ts'o" <tytso@....edu>, Andreas Dilger <adilger@...ger.ca>, Thavatchai Makphaibulchoke <thavatchai.makpahibulchoke@...com>, T Makphaibulchoke <tmac@...com>, Al Viro <viro@...iv.linux.org.uk>, "linux-ext4@...r.kernel.org List" <linux-ext4@...r.kernel.org>, Linux Kernel Mailing List <linux-kernel@...r.kernel.org>, "linux-fsdevel@...r.kernel.org Devel" <linux-fsdevel@...r.kernel.org>, aswin@...com, Linus Torvalds <torvalds@...ux-foundation.org>, aswin_proj@...ts.hp.com Subject: Re: [PATCH v3 0/2] ext4: increase mbcache scalability On 9/11/13 11:49 AM, Eric Sandeen wrote: > On 9/11/13 6:30 AM, Theodore Ts'o wrote: >> On Tue, Sep 10, 2013 at 10:13:16PM -0500, Eric Sandeen wrote: >>> >>> Above doesn't tell us the prevalence of various contexts on the actual system, >>> but they are all under 100 bytes in any case. >> >> OK, so in other words, on your system i_file_acl and i_file_acl_high >> (which is where we store the block # for the external xattr block), >> should always be zero for all inodes, yes? > > Oh, hum - ok, so that would have been the better thing to check (or at > least an additional thing). > > # find / -xdev -exec filefrag -x {} \; | awk -F : '{print $NF}' | sort | uniq -c > > Finds quite a lot that claim to have external blocks, but it seems broken: > > # filefrag -xv /var/lib/yum/repos/x86_64/6Server/epel > Filesystem type is: ef53 > File size of /var/lib/yum/repos/x86_64/6Server/epel is 4096 (1 block, blocksize 4096) > ext logical physical expected length flags > 0 0 32212996252 100 not_aligned,inline > /var/lib/yum/repos/x86_64/6Server/epel: 1 extent found > > So _filefrag_ says it has a block (at a 120T physical address not on my fs!) Oh, this is the special-but-not-documented "print inline extents in bytes not blocks" :( I'll send a patch to ignore inline extents on fiemap calls to make this easier, but in the meantime, neither my RHEL6 root nor my F17 root have any out-of-inode selinux xattrs on 256-byte-inode filesystems. So selinux alone should not be exercising mbcache much, if at all, w/ 256 byte inodes. -Eric -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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