From: Jan Kara <jack@suse.cz> To: linux-fsdevel@vger.kernel.org Cc: Jan Kara <jack@suse.cz>, linux-nvdimm@lists.01.org, linux-mm@kvack.org, linux-ext4@vger.kernel.org Subject: [RFC v3] [PATCH 0/18] DAX page fault locking Date: Mon, 18 Apr 2016 23:35:23 +0200 [thread overview] Message-ID: <1461015341-20153-1-git-send-email-jack@suse.cz> (raw) Hello, this is my third attempt at DAX page fault locking rewrite. The patch set has passed xfstests both with and without DAX mount option on ext4 and xfs for me and also additional page fault beating using the new page fault stress tests I have added to xfstests. So I'd be grateful if you guys could have a closer look at the patches so that they can be merged. Thanks. Changes since v2: - lot of additional ext4 fixes and cleanups - make PMD page faults depend on CONFIG_BROKEN instead of #if 0 - fixed page reference leak when replacing hole page with a pfn - added some reviewed-by tags - rebased on top of current Linus' tree Changes since v1: - handle wakeups of exclusive waiters properly - fix cow fault races - other minor stuff General description The basic idea is that we use a bit in an exceptional radix tree entry as a lock bit and use it similarly to how page lock is used for normal faults. That way we fix races between hole instantiation and read faults of the same index. For now I have disabled PMD faults since there the issues with page fault locking are even worse. Now that Matthew's multi-order radix tree has landed, I can have a look into using that for proper locking of PMD faults but first I want normal pages sorted out. In the end I have decided to implement the bit locking directly in the DAX code. Originally I was thinking we could provide something generic directly in the radix tree code but the functions DAX needs are rather specific. Maybe someone else will have a good idea how to distill some generally useful functions out of what I've implemented for DAX but for now I didn't bother with that. Honza _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm
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From: Jan Kara <jack@suse.cz> To: linux-fsdevel@vger.kernel.org Cc: linux-ext4@vger.kernel.org, linux-mm@kvack.org, Ross Zwisler <ross.zwisler@linux.intel.com>, Dan Williams <dan.j.williams@intel.com>, linux-nvdimm@lists.01.org, Matthew Wilcox <willy@linux.intel.com>, Jan Kara <jack@suse.cz> Subject: [RFC v3] [PATCH 0/18] DAX page fault locking Date: Mon, 18 Apr 2016 23:35:23 +0200 [thread overview] Message-ID: <1461015341-20153-1-git-send-email-jack@suse.cz> (raw) Hello, this is my third attempt at DAX page fault locking rewrite. The patch set has passed xfstests both with and without DAX mount option on ext4 and xfs for me and also additional page fault beating using the new page fault stress tests I have added to xfstests. So I'd be grateful if you guys could have a closer look at the patches so that they can be merged. Thanks. Changes since v2: - lot of additional ext4 fixes and cleanups - make PMD page faults depend on CONFIG_BROKEN instead of #if 0 - fixed page reference leak when replacing hole page with a pfn - added some reviewed-by tags - rebased on top of current Linus' tree Changes since v1: - handle wakeups of exclusive waiters properly - fix cow fault races - other minor stuff General description The basic idea is that we use a bit in an exceptional radix tree entry as a lock bit and use it similarly to how page lock is used for normal faults. That way we fix races between hole instantiation and read faults of the same index. For now I have disabled PMD faults since there the issues with page fault locking are even worse. Now that Matthew's multi-order radix tree has landed, I can have a look into using that for proper locking of PMD faults but first I want normal pages sorted out. In the end I have decided to implement the bit locking directly in the DAX code. Originally I was thinking we could provide something generic directly in the radix tree code but the functions DAX needs are rather specific. Maybe someone else will have a good idea how to distill some generally useful functions out of what I've implemented for DAX but for now I didn't bother with that. Honza -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next reply other threads:[~2016-04-18 21:35 UTC|newest] Thread overview: 122+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-04-18 21:35 Jan Kara [this message] 2016-04-18 21:35 ` [RFC v3] [PATCH 0/18] DAX page fault locking Jan Kara 2016-04-18 21:35 ` [PATCH 01/18] ext4: Handle transient ENOSPC properly for DAX Jan Kara 2016-04-18 21:35 ` Jan Kara 2016-04-18 21:35 ` [PATCH 02/18] ext4: Fix race in transient ENOSPC detection Jan Kara 2016-04-18 21:35 ` Jan Kara 2016-04-18 21:35 ` [PATCH 03/18] DAX: move RADIX_DAX_ definitions to dax.c Jan Kara 2016-04-18 21:35 ` Jan Kara 2016-04-18 21:35 ` [PATCH 04/18] dax: Remove complete_unwritten argument Jan Kara 2016-04-18 21:35 ` Jan Kara 2016-04-18 21:35 ` [PATCH 05/18] ext2: Avoid DAX zeroing to corrupt data Jan Kara 2016-04-18 21:35 ` Jan Kara 2016-04-29 16:30 ` Ross Zwisler 2016-04-29 16:30 ` Ross Zwisler 2016-04-29 16:30 ` Ross Zwisler 2016-04-18 21:35 ` [PATCH 06/18] dax: Remove dead zeroing code from fault handlers Jan Kara 2016-04-18 21:35 ` Jan Kara 2016-04-29 16:48 ` Ross Zwisler 2016-04-18 21:35 ` [PATCH 07/18] ext4: Refactor direct IO code Jan Kara 2016-04-18 21:35 ` Jan Kara 2016-04-18 21:35 ` Jan Kara 2016-04-18 21:35 ` [PATCH 08/18] ext4: Pre-zero allocated blocks for DAX IO Jan Kara 2016-04-18 21:35 ` Jan Kara 2016-04-18 21:35 ` Jan Kara 2016-04-29 18:01 ` Ross Zwisler 2016-04-29 18:01 ` Ross Zwisler 2016-04-29 18:01 ` Ross Zwisler 2016-05-02 13:09 ` Jan Kara 2016-05-02 13:09 ` Jan Kara 2016-04-18 21:35 ` [PATCH 09/18] dax: Remove zeroing from dax_io() Jan Kara 2016-04-18 21:35 ` Jan Kara 2016-04-18 21:35 ` Jan Kara 2016-04-29 18:56 ` Ross Zwisler 2016-04-29 18:56 ` Ross Zwisler 2016-04-18 21:35 ` [PATCH 10/18] dax: Remove pointless writeback from dax_do_io() Jan Kara 2016-04-18 21:35 ` Jan Kara 2016-04-18 21:35 ` Jan Kara 2016-04-29 19:00 ` Ross Zwisler 2016-04-29 19:00 ` Ross Zwisler 2016-04-29 19:00 ` Ross Zwisler 2016-04-18 21:35 ` [PATCH 11/18] dax: Fix condition for filling of PMD holes Jan Kara 2016-04-18 21:35 ` Jan Kara 2016-04-29 19:08 ` Ross Zwisler 2016-04-29 19:08 ` Ross Zwisler 2016-04-29 19:08 ` Ross Zwisler 2016-05-02 13:16 ` Jan Kara 2016-05-02 13:16 ` Jan Kara 2016-04-18 21:35 ` [PATCH 12/18] dax: Remove redundant inode size checks Jan Kara 2016-04-18 21:35 ` Jan Kara 2016-04-18 21:35 ` Jan Kara 2016-04-18 21:35 ` [PATCH 13/18] dax: Make huge page handling depend of CONFIG_BROKEN Jan Kara 2016-04-18 21:35 ` Jan Kara 2016-04-18 21:35 ` Jan Kara 2016-04-29 19:53 ` Ross Zwisler 2016-04-29 19:53 ` Ross Zwisler 2016-05-02 13:19 ` Jan Kara 2016-05-02 13:19 ` Jan Kara 2016-05-02 13:19 ` Jan Kara 2016-04-18 21:35 ` [PATCH 14/18] dax: Define DAX lock bit for radix tree exceptional entry Jan Kara 2016-04-18 21:35 ` Jan Kara 2016-04-18 21:35 ` Jan Kara 2016-04-29 20:03 ` Ross Zwisler 2016-04-29 20:03 ` Ross Zwisler 2016-04-29 20:03 ` Ross Zwisler 2016-04-18 21:35 ` [PATCH 15/18] dax: Allow DAX code to replace exceptional entries Jan Kara 2016-04-18 21:35 ` Jan Kara 2016-04-18 21:35 ` Jan Kara 2016-04-29 20:29 ` Ross Zwisler 2016-04-29 20:29 ` Ross Zwisler 2016-04-18 21:35 ` [PATCH 16/18] dax: New fault locking Jan Kara 2016-04-18 21:35 ` Jan Kara 2016-04-27 4:27 ` NeilBrown 2016-04-27 4:27 ` NeilBrown 2016-05-06 4:13 ` Ross Zwisler 2016-05-06 4:13 ` Ross Zwisler 2016-05-06 4:13 ` Ross Zwisler 2016-05-10 12:27 ` Jan Kara 2016-05-10 12:27 ` Jan Kara 2016-05-11 19:26 ` Ross Zwisler 2016-05-11 19:26 ` Ross Zwisler 2016-05-12 7:58 ` Jan Kara 2016-05-12 7:58 ` Jan Kara 2016-04-18 21:35 ` [PATCH 17/18] dax: Use radix tree entry lock to protect cow faults Jan Kara 2016-04-18 21:35 ` Jan Kara 2016-04-18 21:35 ` Jan Kara 2016-04-19 11:46 ` Jerome Glisse 2016-04-19 11:46 ` Jerome Glisse 2016-04-19 11:46 ` Jerome Glisse 2016-04-19 14:33 ` Jan Kara 2016-04-19 14:33 ` Jan Kara 2016-04-19 14:33 ` Jan Kara 2016-04-19 15:19 ` Jerome Glisse 2016-04-19 15:19 ` Jerome Glisse 2016-04-19 15:19 ` Jerome Glisse 2016-04-19 15:19 ` Jerome Glisse 2016-04-18 21:35 ` [PATCH 18/18] dax: Remove i_mmap_lock protection Jan Kara 2016-04-18 21:35 ` Jan Kara 2016-04-18 21:35 ` Jan Kara 2016-05-06 3:35 ` [RFC v3] [PATCH 0/18] DAX page fault locking Ross Zwisler 2016-05-06 3:35 ` Ross Zwisler 2016-05-06 20:33 ` Ross Zwisler 2016-05-06 20:33 ` Ross Zwisler 2016-05-09 9:38 ` Jan Kara 2016-05-09 9:38 ` Jan Kara 2016-05-09 9:38 ` Jan Kara 2016-05-10 15:28 ` Jan Kara 2016-05-10 15:28 ` Jan Kara 2016-05-10 15:28 ` Jan Kara 2016-05-10 20:30 ` Ross Zwisler 2016-05-10 20:30 ` Ross Zwisler 2016-05-10 20:30 ` Ross Zwisler 2016-05-10 22:39 ` Ross Zwisler 2016-05-10 22:39 ` Ross Zwisler 2016-05-11 9:19 ` Jan Kara 2016-05-11 9:19 ` Jan Kara 2016-05-11 9:19 ` Jan Kara 2016-05-11 15:52 ` Ross Zwisler 2016-05-11 15:52 ` Ross Zwisler 2016-05-11 15:52 ` Ross Zwisler 2016-05-09 21:28 ` Verma, Vishal L 2016-05-10 11:52 ` Jan Kara 2016-05-10 11:52 ` Jan Kara
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