From b31dc66a54ad986b6b73bdc49c8efc17cbad1833 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Tue, 13 Jun 2006 08:26:10 +0200 Subject: [PATCH] Kill PF_SYNCWRITE flag A process flag to indicate whether we are doing sync io is incredibly ugly. It also causes performance problems when one does a lot of async io and then proceeds to sync it. Part of the io will go out as async, and the other part as sync. This causes a disconnect between the previously submitted io and the synced io. For io schedulers such as CFQ, this will cause us lost merges and suboptimal behaviour in scheduling. Remove PF_SYNCWRITE completely from the fsync/msync paths, and let the O_DIRECT path just directly indicate that the writes are sync by using WRITE_SYNC instead. Signed-off-by: Jens Axboe --- include/linux/blkdev.h | 2 ++ include/linux/sched.h | 11 +++++------ 2 files changed, 7 insertions(+), 6 deletions(-) (limited to 'include') diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 3457e7b97363..482a21d67627 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -241,6 +241,7 @@ enum rq_flag_bits { __REQ_PM_RESUME, /* resume request */ __REQ_PM_SHUTDOWN, /* shutdown request */ __REQ_ORDERED_COLOR, /* is before or after barrier */ + __REQ_RW_SYNC, /* request is sync (O_DIRECT) */ __REQ_NR_BITS, /* stops here */ }; @@ -270,6 +271,7 @@ enum rq_flag_bits { #define REQ_PM_RESUME (1 << __REQ_PM_RESUME) #define REQ_PM_SHUTDOWN (1 << __REQ_PM_SHUTDOWN) #define REQ_ORDERED_COLOR (1 << __REQ_ORDERED_COLOR) +#define REQ_RW_SYNC (1 << __REQ_RW_SYNC) /* * State information carried for REQ_PM_SUSPEND and REQ_PM_RESUME diff --git a/include/linux/sched.h b/include/linux/sched.h index a9d23c7d1b25..38b4791e6a5d 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -941,12 +941,11 @@ static inline void put_task_struct(struct task_struct *t) #define PF_KSWAPD 0x00040000 /* I am kswapd */ #define PF_SWAPOFF 0x00080000 /* I am in swapoff */ #define PF_LESS_THROTTLE 0x00100000 /* Throttle me less: I clean memory */ -#define PF_SYNCWRITE 0x00200000 /* I am doing a sync write */ -#define PF_BORROWED_MM 0x00400000 /* I am a kthread doing use_mm */ -#define PF_RANDOMIZE 0x00800000 /* randomize virtual address space */ -#define PF_SWAPWRITE 0x01000000 /* Allowed to write to swap */ -#define PF_SPREAD_PAGE 0x04000000 /* Spread page cache over cpuset */ -#define PF_SPREAD_SLAB 0x08000000 /* Spread some slab caches over cpuset */ +#define PF_BORROWED_MM 0x00200000 /* I am a kthread doing use_mm */ +#define PF_RANDOMIZE 0x00400000 /* randomize virtual address space */ +#define PF_SWAPWRITE 0x00800000 /* Allowed to write to swap */ +#define PF_SPREAD_PAGE 0x01000000 /* Spread page cache over cpuset */ +#define PF_SPREAD_SLAB 0x02000000 /* Spread some slab caches over cpuset */ #define PF_MEMPOLICY 0x10000000 /* Non-default NUMA mempolicy */ /* -- cgit v1.2.3