If the current process is in a non-root memcg, then balance_dirty_pages() will consider the memcg dirty limits as well as the system-wide limits. This allows different cgroups to have distinct dirty limits which trigger direct and background writeback at different levels. If called with a mem_cgroup, then throttle_vm_writeout() queries the given cgroup for its dirty memory usage limits. Signed-off-by: Andrea Righi <arighi@xxxxxxxxxxx> Signed-off-by: Greg Thelen <gthelen@xxxxxxxxxx> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> Acked-by: Wu Fengguang <fengguang.wu@xxxxxxxxx> --- include/linux/writeback.h | 3 ++- mm/page-writeback.c | 35 +++++++++++++++++++++++++++++------ mm/vmscan.c | 2 +- 3 files changed, 32 insertions(+), 8 deletions(-) diff --git a/include/linux/writeback.h b/include/linux/writeback.h index 4f5c0d2..0b4b851 100644 --- a/include/linux/writeback.h +++ b/include/linux/writeback.h @@ -8,6 +8,7 @@ #include <linux/fs.h> struct backing_dev_info; +struct mem_cgroup; /* * fs/fs-writeback.c @@ -91,7 +92,7 @@ void laptop_mode_timer_fn(unsigned long data); #else static inline void laptop_sync_completion(void) { } #endif -void throttle_vm_writeout(gfp_t gfp_mask); +void throttle_vm_writeout(gfp_t gfp_mask, struct mem_cgroup *mem_cgroup); /* These are exported to sysctl. */ extern int dirty_background_ratio; diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 62fcf3d..30c265b 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -473,7 +473,8 @@ unsigned long bdi_dirty_limit(struct backing_dev_info *bdi, unsigned long dirty) * data. It looks at the number of dirty pages in the machine and will force * the caller to perform writeback if the system is over `vm_dirty_ratio'. * If we're over `background_thresh' then the writeback threads are woken to - * perform some writeout. + * perform some writeout. The current task may belong to a cgroup with + * dirty limits, which are also checked. */ static void balance_dirty_pages(struct address_space *mapping, unsigned long write_chunk) @@ -488,6 +489,8 @@ static void balance_dirty_pages(struct address_space *mapping, bool dirty_exceeded = false; struct backing_dev_info *bdi = mapping->backing_dev_info; + mem_cgroup_balance_dirty_pages(mapping, write_chunk); + for (;;) { struct writeback_control wbc = { .sync_mode = WB_SYNC_NONE, @@ -651,23 +654,43 @@ void balance_dirty_pages_ratelimited_nr(struct address_space *mapping, } EXPORT_SYMBOL(balance_dirty_pages_ratelimited_nr); -void throttle_vm_writeout(gfp_t gfp_mask) +/* + * Throttle the current task if it is near dirty memory usage limits. Both + * global dirty memory limits and (if @mem_cgroup is given) per-cgroup dirty + * memory limits are checked. + * + * If near limits, then wait for usage to drop. Dirty usage should drop because + * dirty producers should have used balance_dirty_pages(), which would have + * scheduled writeback. + */ +void throttle_vm_writeout(gfp_t gfp_mask, struct mem_cgroup *mem_cgroup) { unsigned long background_thresh; unsigned long dirty_thresh; + struct dirty_info memcg_info; + bool do_memcg; for ( ; ; ) { global_dirty_limits(&background_thresh, &dirty_thresh); + do_memcg = mem_cgroup && + mem_cgroup_hierarchical_dirty_info( + determine_dirtyable_memory(), mem_cgroup, + &memcg_info); /* * Boost the allowable dirty threshold a bit for page * allocators so they don't get DoS'ed by heavy writers */ dirty_thresh += dirty_thresh / 10; /* wheeee... */ - - if (global_page_state(NR_UNSTABLE_NFS) + - global_page_state(NR_WRITEBACK) <= dirty_thresh) - break; + if (do_memcg) + memcg_info.dirty_thresh += memcg_info.dirty_thresh / 10; + + if ((global_page_state(NR_UNSTABLE_NFS) + + global_page_state(NR_WRITEBACK) <= dirty_thresh) && + (!do_memcg || + (memcg_info.nr_unstable_nfs + + memcg_info.nr_writeback <= memcg_info.dirty_thresh))) + break; congestion_wait(BLK_RW_ASYNC, HZ/10); /* diff --git a/mm/vmscan.c b/mm/vmscan.c index 292582c..66324a4 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1953,7 +1953,7 @@ restart: sc->nr_scanned - nr_scanned, sc)) goto restart; - throttle_vm_writeout(sc->gfp_mask); + throttle_vm_writeout(sc->gfp_mask, sc->mem_cgroup); } /* -- 1.7.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html