[PATCH 2/3] xfs: refine the allocation stack switch
Brian Foster
bfoster at redhat.com
Mon Jul 14 07:02:23 CDT 2014
On Mon, Jul 14, 2014 at 02:48:58PM +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner at redhat.com>
>
...
>
> Signed-off-by: Dave Chinner <dchinner at redhat.com>
> ---
Looks good...
Reviewed-by: Brian Foster <bfoster at redhat.com>
> fs/xfs/xfs_bmap.c | 7 ++---
> fs/xfs/xfs_bmap.h | 4 +--
> fs/xfs/xfs_bmap_util.c | 43 --------------------------
> fs/xfs/xfs_bmap_util.h | 13 +++-----
> fs/xfs/xfs_btree.c | 82 +++++++++++++++++++++++++++++++++++++++++++++++++-
> fs/xfs/xfs_iomap.c | 3 +-
> 6 files changed, 90 insertions(+), 62 deletions(-)
>
> diff --git a/fs/xfs/xfs_bmap.c b/fs/xfs/xfs_bmap.c
> index 96175df..75c3fe5 100644
> --- a/fs/xfs/xfs_bmap.c
> +++ b/fs/xfs/xfs_bmap.c
> @@ -4298,8 +4298,8 @@ xfs_bmapi_delay(
> }
>
>
> -int
> -__xfs_bmapi_allocate(
> +static int
> +xfs_bmapi_allocate(
> struct xfs_bmalloca *bma)
> {
> struct xfs_mount *mp = bma->ip->i_mount;
> @@ -4578,9 +4578,6 @@ xfs_bmapi_write(
> bma.flist = flist;
> bma.firstblock = firstblock;
>
> - if (flags & XFS_BMAPI_STACK_SWITCH)
> - bma.stack_switch = 1;
> -
> while (bno < end && n < *nmap) {
> inhole = eof || bma.got.br_startoff > bno;
> wasdelay = !inhole && isnullstartblock(bma.got.br_startblock);
> diff --git a/fs/xfs/xfs_bmap.h b/fs/xfs/xfs_bmap.h
> index 38ba36e..b879ca5 100644
> --- a/fs/xfs/xfs_bmap.h
> +++ b/fs/xfs/xfs_bmap.h
> @@ -77,7 +77,6 @@ typedef struct xfs_bmap_free
> * from written to unwritten, otherwise convert from unwritten to written.
> */
> #define XFS_BMAPI_CONVERT 0x040
> -#define XFS_BMAPI_STACK_SWITCH 0x080
>
> #define XFS_BMAPI_FLAGS \
> { XFS_BMAPI_ENTIRE, "ENTIRE" }, \
> @@ -86,8 +85,7 @@ typedef struct xfs_bmap_free
> { XFS_BMAPI_PREALLOC, "PREALLOC" }, \
> { XFS_BMAPI_IGSTATE, "IGSTATE" }, \
> { XFS_BMAPI_CONTIG, "CONTIG" }, \
> - { XFS_BMAPI_CONVERT, "CONVERT" }, \
> - { XFS_BMAPI_STACK_SWITCH, "STACK_SWITCH" }
> + { XFS_BMAPI_CONVERT, "CONVERT" }
>
>
> static inline int xfs_bmapi_aflag(int w)
> diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
> index 057f671..64731ef 100644
> --- a/fs/xfs/xfs_bmap_util.c
> +++ b/fs/xfs/xfs_bmap_util.c
> @@ -249,49 +249,6 @@ xfs_bmap_rtalloc(
> }
>
> /*
> - * Stack switching interfaces for allocation
> - */
> -static void
> -xfs_bmapi_allocate_worker(
> - struct work_struct *work)
> -{
> - struct xfs_bmalloca *args = container_of(work,
> - struct xfs_bmalloca, work);
> - unsigned long pflags;
> -
> - /* we are in a transaction context here */
> - current_set_flags_nested(&pflags, PF_FSTRANS);
> -
> - args->result = __xfs_bmapi_allocate(args);
> - complete(args->done);
> -
> - current_restore_flags_nested(&pflags, PF_FSTRANS);
> -}
> -
> -/*
> - * Some allocation requests often come in with little stack to work on. Push
> - * them off to a worker thread so there is lots of stack to use. Otherwise just
> - * call directly to avoid the context switch overhead here.
> - */
> -int
> -xfs_bmapi_allocate(
> - struct xfs_bmalloca *args)
> -{
> - DECLARE_COMPLETION_ONSTACK(done);
> -
> - if (!args->stack_switch)
> - return __xfs_bmapi_allocate(args);
> -
> -
> - args->done = &done;
> - INIT_WORK_ONSTACK(&args->work, xfs_bmapi_allocate_worker);
> - queue_work(xfs_alloc_wq, &args->work);
> - wait_for_completion(&done);
> - destroy_work_on_stack(&args->work);
> - return args->result;
> -}
> -
> -/*
> * Check if the endoff is outside the last extent. If so the caller will grow
> * the allocation to a stripe unit boundary. All offsets are considered outside
> * the end of file for an empty fork, so 1 is returned in *eof in that case.
> diff --git a/fs/xfs/xfs_bmap_util.h b/fs/xfs/xfs_bmap_util.h
> index 935ed2b..2fdb72d 100644
> --- a/fs/xfs/xfs_bmap_util.h
> +++ b/fs/xfs/xfs_bmap_util.h
> @@ -50,12 +50,11 @@ struct xfs_bmalloca {
> xfs_extlen_t total; /* total blocks needed for xaction */
> xfs_extlen_t minlen; /* minimum allocation size (blocks) */
> xfs_extlen_t minleft; /* amount must be left after alloc */
> - char eof; /* set if allocating past last extent */
> - char wasdel; /* replacing a delayed allocation */
> - char userdata;/* set if is user data */
> - char aeof; /* allocated space at eof */
> - char conv; /* overwriting unwritten extents */
> - char stack_switch;
> + bool eof; /* set if allocating past last extent */
> + bool wasdel; /* replacing a delayed allocation */
> + bool userdata;/* set if is user data */
> + bool aeof; /* allocated space at eof */
> + bool conv; /* overwriting unwritten extents */
> int flags;
> struct completion *done;
> struct work_struct work;
> @@ -65,8 +64,6 @@ struct xfs_bmalloca {
> int xfs_bmap_finish(struct xfs_trans **tp, struct xfs_bmap_free *flist,
> int *committed);
> int xfs_bmap_rtalloc(struct xfs_bmalloca *ap);
> -int xfs_bmapi_allocate(struct xfs_bmalloca *args);
> -int __xfs_bmapi_allocate(struct xfs_bmalloca *args);
> int xfs_bmap_eof(struct xfs_inode *ip, xfs_fileoff_t endoff,
> int whichfork, int *eof);
> int xfs_bmap_count_blocks(struct xfs_trans *tp, struct xfs_inode *ip,
> diff --git a/fs/xfs/xfs_btree.c b/fs/xfs/xfs_btree.c
> index bf810c6..cf893bc 100644
> --- a/fs/xfs/xfs_btree.c
> +++ b/fs/xfs/xfs_btree.c
> @@ -33,6 +33,7 @@
> #include "xfs_error.h"
> #include "xfs_trace.h"
> #include "xfs_cksum.h"
> +#include "xfs_alloc.h"
>
> /*
> * Cursor allocation zone.
> @@ -2323,7 +2324,7 @@ error1:
> * record (to be inserted into parent).
> */
> STATIC int /* error */
> -xfs_btree_split(
> +__xfs_btree_split(
> struct xfs_btree_cur *cur,
> int level,
> union xfs_btree_ptr *ptrp,
> @@ -2503,6 +2504,85 @@ error0:
> return error;
> }
>
> +struct xfs_btree_split_args {
> + struct xfs_btree_cur *cur;
> + int level;
> + union xfs_btree_ptr *ptrp;
> + union xfs_btree_key *key;
> + struct xfs_btree_cur **curp;
> + int *stat; /* success/failure */
> + int result;
> + bool kswapd; /* allocation in kswapd context */
> + struct completion *done;
> + struct work_struct work;
> +};
> +
> +/*
> + * Stack switching interfaces for allocation
> + */
> +static void
> +xfs_btree_split_worker(
> + struct work_struct *work)
> +{
> + struct xfs_btree_split_args *args = container_of(work,
> + struct xfs_btree_split_args, work);
> + unsigned long pflags;
> + unsigned long new_pflags = PF_FSTRANS;
> +
> + /*
> + * we are in a transaction context here, but may also be doing work
> + * in kswapd context, and hence we may need to inherit that state
> + * temporarily to ensure that we don't block waiting for memory reclaim
> + * in any way.
> + */
> + if (args->kswapd)
> + new_pflags |= PF_MEMALLOC | PF_SWAPWRITE | PF_KSWAPD;
> +
> + current_set_flags_nested(&pflags, new_pflags);
> +
> + args->result = __xfs_btree_split(args->cur, args->level, args->ptrp,
> + args->key, args->curp, args->stat);
> + complete(args->done);
> +
> + current_restore_flags_nested(&pflags, new_pflags);
> +}
> +
> +/*
> + * BMBT split requests often come in with little stack to work on. Push
> + * them off to a worker thread so there is lots of stack to use. For the other
> + * btree types, just call directly to avoid the context switch overhead here.
> + */
> +STATIC int /* error */
> +xfs_btree_split(
> + struct xfs_btree_cur *cur,
> + int level,
> + union xfs_btree_ptr *ptrp,
> + union xfs_btree_key *key,
> + struct xfs_btree_cur **curp,
> + int *stat) /* success/failure */
> +{
> + struct xfs_btree_split_args args;
> + DECLARE_COMPLETION_ONSTACK(done);
> +
> + if (cur->bc_btnum != XFS_BTNUM_BMAP)
> + return __xfs_btree_split(cur, level, ptrp, key, curp, stat);
> +
> + args.cur = cur;
> + args.level = level;
> + args.ptrp = ptrp;
> + args.key = key;
> + args.curp = curp;
> + args.stat = stat;
> + args.done = &done;
> + args.kswapd = current_is_kswapd();
> + INIT_WORK_ONSTACK(&args.work, xfs_btree_split_worker);
> + queue_work(xfs_alloc_wq, &args.work);
> + wait_for_completion(&done);
> + destroy_work_on_stack(&args.work);
> + return args.result;
> +}
> +
> +
> /*
> * Copy the old inode root contents into a real block and make the
> * broot point to it.
> diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
> index 6c5eb4c..6d3ec2b 100644
> --- a/fs/xfs/xfs_iomap.c
> +++ b/fs/xfs/xfs_iomap.c
> @@ -749,8 +749,7 @@ xfs_iomap_write_allocate(
> * pointer that the caller gave to us.
> */
> error = xfs_bmapi_write(tp, ip, map_start_fsb,
> - count_fsb,
> - XFS_BMAPI_STACK_SWITCH,
> + count_fsb, 0,
> &first_block, 1,
> imap, &nimaps, &free_list);
> if (error)
> --
> 2.0.0
>
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