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-rw-r--r--drivers/block/loop.c2
-rw-r--r--fs/nfsd/vfs.c9
-rw-r--r--include/linux/sched.h3
-rw-r--r--kernel/sys.c2
-rw-r--r--mm/page-writeback.c41
-rw-r--r--mm/vmscan.c4
6 files changed, 44 insertions, 17 deletions
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);
}
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.