| Message ID | 20200224123047.32506-5-sjpark@amazon.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Introduce Data Access MONitor (DAMON) | expand |
On Mon, 24 Feb 2020 13:30:37 +0100 SeongJae Park <sjpark@amazon.com> wrote: > From: SeongJae Park <sjpark@amazon.de> > > Only a number of parts in the virtual address space of the processes is > mapped to physical memory and accessed. Thus, tracking the unmapped > address regions is just wasteful. However, tracking every memory > mapping change might incur an overhead. For the reason, DAMON applies > the dynamic memory mapping changes to the tracking regions only for each > of a user-specified time interval (``regions update interval``). > > Signed-off-by: SeongJae Park <sjpark@amazon.de> Trivial inline. Otherwise makes sense to me. > --- > mm/damon.c | 99 +++++++++++++++++++++++++++++++++++++++++++++++++++--- > 1 file changed, 95 insertions(+), 4 deletions(-) > > diff --git a/mm/damon.c b/mm/damon.c > index 1c8bb71bbce9..6a17408e83c2 100644 > --- a/mm/damon.c > +++ b/mm/damon.c > @@ -59,17 +59,22 @@ struct damon_task { > /* > * For each 'sample_interval', DAMON checks whether each region is accessed or > * not. It aggregates and keeps the access information (number of accesses to > - * each region) for each 'aggr_interval' time. > + * each region) for each 'aggr_interval' time. And for each > + * 'regions_update_interval', damon checks whether the memory mapping of the > + * target tasks has changed (e.g., by mmap() calls from the applications) and > + * applies the changes. > * > * All time intervals are in micro-seconds. > */ > struct damon_ctx { > unsigned long sample_interval; > unsigned long aggr_interval; > + unsigned long regions_update_interval; > unsigned long min_nr_regions; > unsigned long max_nr_regions; > > struct timespec64 last_aggregation; > + struct timespec64 last_regions_update; > > struct task_struct *kdamond; > bool kdamond_stop; > @@ -671,6 +676,87 @@ static void kdamond_split_regions(struct damon_ctx *ctx) > damon_split_regions_of(ctx, t); > } > > +/* > + * Check whether it is time to check and apply the dynamic mmap changes > + * > + * Returns true if it is. > + */ > +static bool kdamond_need_update_regions(struct damon_ctx *ctx) > +{ > + return damon_check_reset_time_interval(&ctx->last_regions_update, > + ctx->regions_update_interval); > +} > + > +static bool damon_intersect(struct damon_region *r, struct region *re) > +{ > + return !(r->vm_end <= re->start || re->end <= r->vm_start); > +} > + > +/* > + * Update damon regions for the three big regions of the given task > + * > + * t the given task > + * bregions the three big regions of the task > + */ > +static void damon_apply_three_regions(struct damon_ctx *ctx, > + struct damon_task *t, struct region bregions[3]) > +{ > + struct damon_region *r, *next; > + unsigned int i = 0; > + > + /* Remove regions which isn't in the three big regions now */ > + damon_for_each_region_safe(r, next, t) { > + for (i = 0; i < 3; i++) { > + if (damon_intersect(r, &bregions[i])) > + break; > + } > + if (i == 3) > + damon_destroy_region(r); > + } > + > + /* Adjust intersecting regions to fit with the threee big regions */ three > + for (i = 0; i < 3; i++) { > + struct damon_region *first = NULL, *last; > + struct damon_region *newr; > + struct region *br; > + > + br = &bregions[i]; > + /* Get the first and last regions which intersects with br */ > + damon_for_each_region(r, t) { > + if (damon_intersect(r, br)) { > + if (!first) > + first = r; > + last = r; > + } > + if (r->vm_start >= br->end) > + break; > + } > + if (!first) { > + /* no damon_region intersects with this big region */ > + newr = damon_new_region(ctx, br->start, br->end); > + damon_add_region(newr, damon_prev_region(r), r); > + } else { > + first->vm_start = br->start; > + last->vm_end = br->end; > + } > + } > +} > + > +/* > + * Update regions for current memory mappings > + */ > +static void kdamond_update_regions(struct damon_ctx *ctx) > +{ > + struct region three_regions[3]; > + struct damon_task *t; > + > + damon_for_each_task(ctx, t) { > + if (damon_three_regions_of(t, three_regions)) > + continue; > + damon_apply_three_regions(ctx, t, three_regions); > + } > +} > + > /* > * Check whether current monitoring should be stopped > * > @@ -735,6 +821,9 @@ static int kdamond_fn(void *data) > kdamond_split_regions(ctx); > } > > + if (kdamond_need_update_regions(ctx)) > + kdamond_update_regions(ctx); > + > usleep_range(ctx->sample_interval, ctx->sample_interval + 1); > } > damon_for_each_task(ctx, t) { > @@ -820,6 +909,7 @@ static int damon_set_pids(struct damon_ctx *ctx, > * > * sample_int time interval between samplings > * aggr_int time interval between aggregations > + * regions_update_int time interval between vma update checks > * min_nr_reg minimal number of regions > * max_nr_reg maximum number of regions > * > @@ -828,9 +918,9 @@ static int damon_set_pids(struct damon_ctx *ctx, > * > * Returns 0 on success, negative error code otherwise. > */ > -static int damon_set_attrs(struct damon_ctx *ctx, > - unsigned long sample_int, unsigned long aggr_int, > - unsigned long min_nr_reg, unsigned long max_nr_reg) > +static int damon_set_attrs(struct damon_ctx *ctx, unsigned long sample_int, > + unsigned long aggr_int, unsigned long regions_update_int, > + unsigned long min_nr_reg, unsigned long max_nr_reg) > { > if (min_nr_reg < 3) { > pr_err("min_nr_regions (%lu) should be bigger than 2\n", > @@ -845,6 +935,7 @@ static int damon_set_attrs(struct damon_ctx *ctx, > > ctx->sample_interval = sample_int; > ctx->aggr_interval = aggr_int; > + ctx->regions_update_interval = regions_update_int; > ctx->min_nr_regions = min_nr_reg; > ctx->max_nr_regions = max_nr_reg; > return 0;
diff --git a/mm/damon.c b/mm/damon.c index 1c8bb71bbce9..6a17408e83c2 100644 --- a/mm/damon.c +++ b/mm/damon.c @@ -59,17 +59,22 @@ struct damon_task { /* * For each 'sample_interval', DAMON checks whether each region is accessed or * not. It aggregates and keeps the access information (number of accesses to - * each region) for each 'aggr_interval' time. + * each region) for each 'aggr_interval' time. And for each + * 'regions_update_interval', damon checks whether the memory mapping of the + * target tasks has changed (e.g., by mmap() calls from the applications) and + * applies the changes. * * All time intervals are in micro-seconds. */ struct damon_ctx { unsigned long sample_interval; unsigned long aggr_interval; + unsigned long regions_update_interval; unsigned long min_nr_regions; unsigned long max_nr_regions; struct timespec64 last_aggregation; + struct timespec64 last_regions_update; struct task_struct *kdamond; bool kdamond_stop; @@ -671,6 +676,87 @@ static void kdamond_split_regions(struct damon_ctx *ctx) damon_split_regions_of(ctx, t); } +/* + * Check whether it is time to check and apply the dynamic mmap changes + * + * Returns true if it is. + */ +static bool kdamond_need_update_regions(struct damon_ctx *ctx) +{ + return damon_check_reset_time_interval(&ctx->last_regions_update, + ctx->regions_update_interval); +} + +static bool damon_intersect(struct damon_region *r, struct region *re) +{ + return !(r->vm_end <= re->start || re->end <= r->vm_start); +} + +/* + * Update damon regions for the three big regions of the given task + * + * t the given task + * bregions the three big regions of the task + */ +static void damon_apply_three_regions(struct damon_ctx *ctx, + struct damon_task *t, struct region bregions[3]) +{ + struct damon_region *r, *next; + unsigned int i = 0; + + /* Remove regions which isn't in the three big regions now */ + damon_for_each_region_safe(r, next, t) { + for (i = 0; i < 3; i++) { + if (damon_intersect(r, &bregions[i])) + break; + } + if (i == 3) + damon_destroy_region(r); + } + + /* Adjust intersecting regions to fit with the threee big regions */ + for (i = 0; i < 3; i++) { + struct damon_region *first = NULL, *last; + struct damon_region *newr; + struct region *br; + + br = &bregions[i]; + /* Get the first and last regions which intersects with br */ + damon_for_each_region(r, t) { + if (damon_intersect(r, br)) { + if (!first) + first = r; + last = r; + } + if (r->vm_start >= br->end) + break; + } + if (!first) { + /* no damon_region intersects with this big region */ + newr = damon_new_region(ctx, br->start, br->end); + damon_add_region(newr, damon_prev_region(r), r); + } else { + first->vm_start = br->start; + last->vm_end = br->end; + } + } +} + +/* + * Update regions for current memory mappings + */ +static void kdamond_update_regions(struct damon_ctx *ctx) +{ + struct region three_regions[3]; + struct damon_task *t; + + damon_for_each_task(ctx, t) { + if (damon_three_regions_of(t, three_regions)) + continue; + damon_apply_three_regions(ctx, t, three_regions); + } +} + /* * Check whether current monitoring should be stopped * @@ -735,6 +821,9 @@ static int kdamond_fn(void *data) kdamond_split_regions(ctx); } + if (kdamond_need_update_regions(ctx)) + kdamond_update_regions(ctx); + usleep_range(ctx->sample_interval, ctx->sample_interval + 1); } damon_for_each_task(ctx, t) { @@ -820,6 +909,7 @@ static int damon_set_pids(struct damon_ctx *ctx, * * sample_int time interval between samplings * aggr_int time interval between aggregations + * regions_update_int time interval between vma update checks * min_nr_reg minimal number of regions * max_nr_reg maximum number of regions * @@ -828,9 +918,9 @@ static int damon_set_pids(struct damon_ctx *ctx, * * Returns 0 on success, negative error code otherwise. */ -static int damon_set_attrs(struct damon_ctx *ctx, - unsigned long sample_int, unsigned long aggr_int, - unsigned long min_nr_reg, unsigned long max_nr_reg) +static int damon_set_attrs(struct damon_ctx *ctx, unsigned long sample_int, + unsigned long aggr_int, unsigned long regions_update_int, + unsigned long min_nr_reg, unsigned long max_nr_reg) { if (min_nr_reg < 3) { pr_err("min_nr_regions (%lu) should be bigger than 2\n", @@ -845,6 +935,7 @@ static int damon_set_attrs(struct damon_ctx *ctx, ctx->sample_interval = sample_int; ctx->aggr_interval = aggr_int; + ctx->regions_update_interval = regions_update_int; ctx->min_nr_regions = min_nr_reg; ctx->max_nr_regions = max_nr_reg; return 0;