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Message-ID: <20170109205833.GA14029@birch.djwong.org>
Date: Mon, 9 Jan 2017 12:58:33 -0800
From: "Darrick J. Wong" <darrick.wong@...cle.com>
To: Michal Hocko <mhocko@...nel.org>
Cc: linux-mm@...ck.org, linux-fsdevel@...r.kernel.org,
Andrew Morton <akpm@...ux-foundation.org>,
Dave Chinner <david@...morbit.com>, djwong@...nel.org,
"Theodore Ts'o" <tytso@....edu>, Chris Mason <clm@...com>,
David Sterba <dsterba@...e.cz>, Jan Kara <jack@...e.cz>,
ceph-devel@...r.kernel.org, cluster-devel@...hat.com,
linux-nfs@...r.kernel.org, logfs@...fs.org,
linux-xfs@...r.kernel.org, linux-ext4@...r.kernel.org,
linux-btrfs@...r.kernel.org, linux-mtd@...ts.infradead.org,
reiserfs-devel@...r.kernel.org,
linux-ntfs-dev@...ts.sourceforge.net,
linux-f2fs-devel@...ts.sourceforge.net,
linux-afs@...ts.infradead.org, LKML <linux-kernel@...r.kernel.org>,
Michal Hocko <mhocko@...e.com>
Subject: Re: [PATCH 2/8] xfs: abstract PF_FSTRANS to PF_MEMALLOC_NOFS
On Fri, Jan 06, 2017 at 03:11:01PM +0100, Michal Hocko wrote:
> From: Michal Hocko <mhocko@...e.com>
>
> xfs has defined PF_FSTRANS to declare a scope GFP_NOFS semantic quite
> some time ago. We would like to make this concept more generic and use
> it for other filesystems as well. Let's start by giving the flag a
> more generic name PF_MEMALLOC_NOFS which is in line with an exiting
> PF_MEMALLOC_NOIO already used for the same purpose for GFP_NOIO
> contexts. Replace all PF_FSTRANS usage from the xfs code in the first
> step before we introduce a full API for it as xfs uses the flag directly
> anyway.
>
> This patch doesn't introduce any functional change.
>
> Signed-off-by: Michal Hocko <mhocko@...e.com>
> Reviewed-by: Brian Foster <bfoster@...hat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@...cle.com>
> ---
> fs/xfs/kmem.c | 4 ++--
> fs/xfs/kmem.h | 2 +-
> fs/xfs/libxfs/xfs_btree.c | 2 +-
> fs/xfs/xfs_aops.c | 6 +++---
> fs/xfs/xfs_trans.c | 12 ++++++------
> include/linux/sched.h | 2 ++
> 6 files changed, 15 insertions(+), 13 deletions(-)
>
> diff --git a/fs/xfs/kmem.c b/fs/xfs/kmem.c
> index 339c696bbc01..a76a05dae96b 100644
> --- a/fs/xfs/kmem.c
> +++ b/fs/xfs/kmem.c
> @@ -80,13 +80,13 @@ kmem_zalloc_large(size_t size, xfs_km_flags_t flags)
> * context via PF_MEMALLOC_NOIO to prevent memory reclaim re-entering
> * the filesystem here and potentially deadlocking.
> */
> - if ((current->flags & PF_FSTRANS) || (flags & KM_NOFS))
> + if ((current->flags & PF_MEMALLOC_NOFS) || (flags & KM_NOFS))
> noio_flag = memalloc_noio_save();
>
> lflags = kmem_flags_convert(flags);
> ptr = __vmalloc(size, lflags | __GFP_HIGHMEM | __GFP_ZERO, PAGE_KERNEL);
>
> - if ((current->flags & PF_FSTRANS) || (flags & KM_NOFS))
> + if ((current->flags & PF_MEMALLOC_NOFS) || (flags & KM_NOFS))
> memalloc_noio_restore(noio_flag);
>
> return ptr;
> diff --git a/fs/xfs/kmem.h b/fs/xfs/kmem.h
> index 689f746224e7..d973dbfc2bfa 100644
> --- a/fs/xfs/kmem.h
> +++ b/fs/xfs/kmem.h
> @@ -50,7 +50,7 @@ kmem_flags_convert(xfs_km_flags_t flags)
> lflags = GFP_ATOMIC | __GFP_NOWARN;
> } else {
> lflags = GFP_KERNEL | __GFP_NOWARN;
> - if ((current->flags & PF_FSTRANS) || (flags & KM_NOFS))
> + if ((current->flags & PF_MEMALLOC_NOFS) || (flags & KM_NOFS))
> lflags &= ~__GFP_FS;
> }
>
> diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
> index 21e6a6ab6b9a..a2672ba4dc33 100644
> --- a/fs/xfs/libxfs/xfs_btree.c
> +++ b/fs/xfs/libxfs/xfs_btree.c
> @@ -2866,7 +2866,7 @@ xfs_btree_split_worker(
> struct xfs_btree_split_args *args = container_of(work,
> struct xfs_btree_split_args, work);
> unsigned long pflags;
> - unsigned long new_pflags = PF_FSTRANS;
> + unsigned long new_pflags = PF_MEMALLOC_NOFS;
>
> /*
> * we are in a transaction context here, but may also be doing work
> diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
> index ef382bfb402b..d4094bb55033 100644
> --- a/fs/xfs/xfs_aops.c
> +++ b/fs/xfs/xfs_aops.c
> @@ -189,7 +189,7 @@ xfs_setfilesize_trans_alloc(
> * We hand off the transaction to the completion thread now, so
> * clear the flag here.
> */
> - current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS);
> + current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);
> return 0;
> }
>
> @@ -252,7 +252,7 @@ xfs_setfilesize_ioend(
> * thus we need to mark ourselves as being in a transaction manually.
> * Similarly for freeze protection.
> */
> - current_set_flags_nested(&tp->t_pflags, PF_FSTRANS);
> + current_set_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);
> __sb_writers_acquired(VFS_I(ip)->i_sb, SB_FREEZE_FS);
>
> /* we abort the update if there was an IO error */
> @@ -1015,7 +1015,7 @@ xfs_do_writepage(
> * Given that we do not allow direct reclaim to call us, we should
> * never be called while in a filesystem transaction.
> */
> - if (WARN_ON_ONCE(current->flags & PF_FSTRANS))
> + if (WARN_ON_ONCE(current->flags & PF_MEMALLOC_NOFS))
> goto redirty;
>
> /*
> diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
> index 70f42ea86dfb..f5969c8274fc 100644
> --- a/fs/xfs/xfs_trans.c
> +++ b/fs/xfs/xfs_trans.c
> @@ -134,7 +134,7 @@ xfs_trans_reserve(
> bool rsvd = (tp->t_flags & XFS_TRANS_RESERVE) != 0;
>
> /* Mark this thread as being in a transaction */
> - current_set_flags_nested(&tp->t_pflags, PF_FSTRANS);
> + current_set_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);
>
> /*
> * Attempt to reserve the needed disk blocks by decrementing
> @@ -144,7 +144,7 @@ xfs_trans_reserve(
> if (blocks > 0) {
> error = xfs_mod_fdblocks(tp->t_mountp, -((int64_t)blocks), rsvd);
> if (error != 0) {
> - current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS);
> + current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);
> return -ENOSPC;
> }
> tp->t_blk_res += blocks;
> @@ -221,7 +221,7 @@ xfs_trans_reserve(
> tp->t_blk_res = 0;
> }
>
> - current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS);
> + current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);
>
> return error;
> }
> @@ -914,7 +914,7 @@ __xfs_trans_commit(
>
> xfs_log_commit_cil(mp, tp, &commit_lsn, regrant);
>
> - current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS);
> + current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);
> xfs_trans_free(tp);
>
> /*
> @@ -944,7 +944,7 @@ __xfs_trans_commit(
> if (commit_lsn == -1 && !error)
> error = -EIO;
> }
> - current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS);
> + current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);
> xfs_trans_free_items(tp, NULLCOMMITLSN, !!error);
> xfs_trans_free(tp);
>
> @@ -998,7 +998,7 @@ xfs_trans_cancel(
> xfs_log_done(mp, tp->t_ticket, NULL, false);
>
> /* mark this thread as no longer being in a transaction */
> - current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS);
> + current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);
>
> xfs_trans_free_items(tp, NULLCOMMITLSN, dirty);
> xfs_trans_free(tp);
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index 1531c48f56e2..abeb84604d32 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -2320,6 +2320,8 @@ extern void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut,
> #define PF_FREEZER_SKIP 0x40000000 /* Freezer should not count it as freezable */
> #define PF_SUSPEND_TASK 0x80000000 /* this thread called freeze_processes and should not be frozen */
>
> +#define PF_MEMALLOC_NOFS PF_FSTRANS /* Transition to a more generic GFP_NOFS scope semantic */
> +
> /*
> * Only the _current_ task can read/write to tsk->flags, but other
> * tasks can access tsk->flags in readonly mode for example
> --
> 2.11.0
>
> --
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