diff --git a/drivers/block/loop.c b/drivers/block/loop.c index da693e6a834e..d89c25ba3b89 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -919,7 +919,7 @@ static void loop_unprepare_queue(struct loop_device *lo) static int loop_kthread_worker_fn(void *worker_ptr) { - current->flags |= PF_LESS_THROTTLE | PF_MEMALLOC_NOIO; + current->flags |= PF_LOCAL_THROTTLE | PF_MEMALLOC_NOIO; return kthread_worker_fn(worker_ptr); } diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index 0aa02eb18bd3..c3fbab1753ec 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -979,12 +979,13 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf, if (test_bit(RQ_LOCAL, &rqstp->rq_flags)) /* - * We want less throttling in balance_dirty_pages() - * and shrink_inactive_list() so that nfs to + * We want throttling in balance_dirty_pages() + * and shrink_inactive_list() to only consider + * the backingdev we are writing to, so that nfs to * localhost doesn't cause nfsd to lock up due to all * the client's dirty pages or its congested queue. */ - current->flags |= PF_LESS_THROTTLE; + current->flags |= PF_LOCAL_THROTTLE; exp = fhp->fh_export; use_wgather = (rqstp->rq_vers == 2) && EX_WGATHER(exp); @@ -1037,7 +1038,7 @@ out_nfserr: nfserr = nfserrno(host_err); } if (test_bit(RQ_LOCAL, &rqstp->rq_flags)) - current_restore_flags(pflags, PF_LESS_THROTTLE); + current_restore_flags(pflags, PF_LOCAL_THROTTLE); return nfserr; } diff --git a/include/linux/sched.h b/include/linux/sched.h index 4418f5cb8324..12ef0c753284 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1481,7 +1481,8 @@ extern struct pid *cad_pid; #define PF_KSWAPD 0x00020000 /* I am kswapd */ #define PF_MEMALLOC_NOFS 0x00040000 /* All allocation requests will inherit GFP_NOFS */ #define PF_MEMALLOC_NOIO 0x00080000 /* All allocation requests will inherit GFP_NOIO */ -#define PF_LESS_THROTTLE 0x00100000 /* Throttle me less: I clean memory */ +#define PF_LOCAL_THROTTLE 0x00100000 /* Throttle writes only against the bdi I write to, + * I am cleaning dirty pages from some other bdi. */ #define PF_KTHREAD 0x00200000 /* I am a kernel thread */ #define PF_RANDOMIZE 0x00400000 /* Randomize virtual address space */ #define PF_SWAPWRITE 0x00800000 /* Allowed to write to swap */ diff --git a/kernel/sys.c b/kernel/sys.c index d325f3ab624a..180a2fa33f7f 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -2262,7 +2262,7 @@ int __weak arch_prctl_spec_ctrl_set(struct task_struct *t, unsigned long which, return -EINVAL; } -#define PR_IO_FLUSHER (PF_MEMALLOC_NOIO | PF_LESS_THROTTLE) +#define PR_IO_FLUSHER (PF_MEMALLOC_NOIO | PF_LOCAL_THROTTLE) SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, unsigned long, arg4, unsigned long, arg5) diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 2df6fb174983..7ff2290cf43d 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -387,8 +387,7 @@ static unsigned long global_dirtyable_memory(void) * Calculate @dtc->thresh and ->bg_thresh considering * vm_dirty_{bytes|ratio} and dirty_background_{bytes|ratio}. The caller * must ensure that @dtc->avail is set before calling this function. The - * dirty limits will be lifted by 1/4 for PF_LESS_THROTTLE (ie. nfsd) and - * real-time tasks. + * dirty limits will be lifted by 1/4 for real-time tasks. */ static void domain_dirty_limits(struct dirty_throttle_control *dtc) { @@ -436,7 +435,7 @@ static void domain_dirty_limits(struct dirty_throttle_control *dtc) if (bg_thresh >= thresh) bg_thresh = thresh / 2; tsk = current; - if (tsk->flags & PF_LESS_THROTTLE || rt_task(tsk)) { + if (rt_task(tsk)) { bg_thresh += bg_thresh / 4 + global_wb_domain.dirty_limit / 32; thresh += thresh / 4 + global_wb_domain.dirty_limit / 32; } @@ -486,7 +485,7 @@ static unsigned long node_dirty_limit(struct pglist_data *pgdat) else dirty = vm_dirty_ratio * node_memory / 100; - if (tsk->flags & PF_LESS_THROTTLE || rt_task(tsk)) + if (rt_task(tsk)) dirty += dirty / 4; return dirty; @@ -1653,8 +1652,12 @@ static void balance_dirty_pages(struct bdi_writeback *wb, if (dirty <= dirty_freerun_ceiling(thresh, bg_thresh) && (!mdtc || m_dirty <= dirty_freerun_ceiling(m_thresh, m_bg_thresh))) { - unsigned long intv = dirty_poll_interval(dirty, thresh); - unsigned long m_intv = ULONG_MAX; + unsigned long intv; + unsigned long m_intv; + +free_running: + intv = dirty_poll_interval(dirty, thresh); + m_intv = ULONG_MAX; current->dirty_paused_when = now; current->nr_dirtied = 0; @@ -1673,9 +1676,20 @@ static void balance_dirty_pages(struct bdi_writeback *wb, * Calculate global domain's pos_ratio and select the * global dtc by default. */ - if (!strictlimit) + if (!strictlimit) { wb_dirty_limits(gdtc); + if ((current->flags & PF_LOCAL_THROTTLE) && + gdtc->wb_dirty < + dirty_freerun_ceiling(gdtc->wb_thresh, + gdtc->wb_bg_thresh)) + /* + * LOCAL_THROTTLE tasks must not be throttled + * when below the per-wb freerun ceiling. + */ + goto free_running; + } + dirty_exceeded = (gdtc->wb_dirty > gdtc->wb_thresh) && ((gdtc->dirty > gdtc->thresh) || strictlimit); @@ -1689,9 +1703,20 @@ static void balance_dirty_pages(struct bdi_writeback *wb, * both global and memcg domains. Choose the one * w/ lower pos_ratio. */ - if (!strictlimit) + if (!strictlimit) { wb_dirty_limits(mdtc); + if ((current->flags & PF_LOCAL_THROTTLE) && + mdtc->wb_dirty < + dirty_freerun_ceiling(mdtc->wb_thresh, + mdtc->wb_bg_thresh)) + /* + * LOCAL_THROTTLE tasks must not be + * throttled when below the per-wb + * freerun ceiling. + */ + goto free_running; + } dirty_exceeded |= (mdtc->wb_dirty > mdtc->wb_thresh) && ((mdtc->dirty > mdtc->thresh) || strictlimit); diff --git a/mm/vmscan.c b/mm/vmscan.c index a37c87b5aee2..b2f5deb3603c 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1878,13 +1878,13 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec, /* * If a kernel thread (such as nfsd for loop-back mounts) services - * a backing device by writing to the page cache it sets PF_LESS_THROTTLE. + * a backing device by writing to the page cache it sets PF_LOCAL_THROTTLE. * In that case we should only throttle if the backing device it is * writing to is congested. In other cases it is safe to throttle. */ static int current_may_throttle(void) { - return !(current->flags & PF_LESS_THROTTLE) || + return !(current->flags & PF_LOCAL_THROTTLE) || current->backing_dev_info == NULL || bdi_write_congested(current->backing_dev_info); }