| Message ID | 20190716152656.12255-2-lpf.vector@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mm/vmalloc.c: improve readability and rewrite vmap_area | expand |
On Tue, 16 Jul 2019 23:26:55 +0800 Pengfei Li <lpf.vector@gmail.com> wrote: > From: "Uladzislau Rezki (Sony)" <urezki@gmail.com> > > The busy tree can be quite big, even though the area is freed > or unmapped it still stays there until "purge" logic removes > it. > > 1) Optimize and reduce the size of "busy" tree by removing a > node from it right away as soon as user triggers free paths. > It is possible to do so, because the allocation is done using > another augmented tree. > > The vmalloc test driver shows the difference, for example the > "fix_size_alloc_test" is ~11% better comparing with default > configuration: > > sudo ./test_vmalloc.sh performance > > <default> > Summary: fix_size_alloc_test loops: 1000000 avg: 993985 usec > Summary: full_fit_alloc_test loops: 1000000 avg: 973554 usec > Summary: long_busy_list_alloc_test loops: 1000000 avg: 12617652 usec > <default> > > <this patch> > Summary: fix_size_alloc_test loops: 1000000 avg: 882263 usec > Summary: full_fit_alloc_test loops: 1000000 avg: 973407 usec > Summary: long_busy_list_alloc_test loops: 1000000 avg: 12593929 usec > <this patch> > > 2) Since the busy tree now contains allocated areas only and does > not interfere with lazily free nodes, introduce the new function > show_purge_info() that dumps "unpurged" areas that is propagated > through "/proc/vmallocinfo". > > 3) Eliminate VM_LAZY_FREE flag. > > Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com> This should have included your signed-off-by, since you were on the patch delivery path. (Documentation/process/submitting-patches.rst, section 11). Please send along your signed-off-by?
Thanks. Signed-off-by: Pengfei Li <lpf.vector@gmail.com> On Thu, Jul 25, 2019 at 10:36 AM Andrew Morton <akpm@linux-foundation.org> wrote: > > On Tue, 16 Jul 2019 23:26:55 +0800 Pengfei Li <lpf.vector@gmail.com> wrote: > > > From: "Uladzislau Rezki (Sony)" <urezki@gmail.com> > > > > The busy tree can be quite big, even though the area is freed > > or unmapped it still stays there until "purge" logic removes > > it. > > > > 1) Optimize and reduce the size of "busy" tree by removing a > > node from it right away as soon as user triggers free paths. > > It is possible to do so, because the allocation is done using > > another augmented tree. > > > > The vmalloc test driver shows the difference, for example the > > "fix_size_alloc_test" is ~11% better comparing with default > > configuration: > > > > sudo ./test_vmalloc.sh performance > > > > <default> > > Summary: fix_size_alloc_test loops: 1000000 avg: 993985 usec > > Summary: full_fit_alloc_test loops: 1000000 avg: 973554 usec > > Summary: long_busy_list_alloc_test loops: 1000000 avg: 12617652 usec > > <default> > > > > <this patch> > > Summary: fix_size_alloc_test loops: 1000000 avg: 882263 usec > > Summary: full_fit_alloc_test loops: 1000000 avg: 973407 usec > > Summary: long_busy_list_alloc_test loops: 1000000 avg: 12593929 usec > > <this patch> > > > > 2) Since the busy tree now contains allocated areas only and does > > not interfere with lazily free nodes, introduce the new function > > show_purge_info() that dumps "unpurged" areas that is propagated > > through "/proc/vmallocinfo". > > > > 3) Eliminate VM_LAZY_FREE flag. > > > > Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com> > > This should have included your signed-off-by, since you were on the > patch delivery path. (Documentation/process/submitting-patches.rst, > section 11). > > Please send along your signed-off-by?
diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 4fa8d84599b0..71d8040a8a0b 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -329,7 +329,6 @@ EXPORT_SYMBOL(vmalloc_to_pfn); #define DEBUG_AUGMENT_PROPAGATE_CHECK 0 #define DEBUG_AUGMENT_LOWEST_MATCH_CHECK 0 -#define VM_LAZY_FREE 0x02 #define VM_VM_AREA 0x04 static DEFINE_SPINLOCK(vmap_area_lock); @@ -1276,7 +1275,14 @@ static bool __purge_vmap_area_lazy(unsigned long start, unsigned long end) llist_for_each_entry_safe(va, n_va, valist, purge_list) { unsigned long nr = (va->va_end - va->va_start) >> PAGE_SHIFT; - __free_vmap_area(va); + /* + * Finally insert or merge lazily-freed area. It is + * detached and there is no need to "unlink" it from + * anything. + */ + merge_or_add_vmap_area(va, + &free_vmap_area_root, &free_vmap_area_list); + atomic_long_sub(nr, &vmap_lazy_nr); if (atomic_long_read(&vmap_lazy_nr) < resched_threshold) @@ -1318,6 +1324,10 @@ static void free_vmap_area_noflush(struct vmap_area *va) { unsigned long nr_lazy; + spin_lock(&vmap_area_lock); + unlink_va(va, &vmap_area_root); + spin_unlock(&vmap_area_lock); + nr_lazy = atomic_long_add_return((va->va_end - va->va_start) >> PAGE_SHIFT, &vmap_lazy_nr); @@ -2137,14 +2147,13 @@ struct vm_struct *remove_vm_area(const void *addr) might_sleep(); - va = find_vmap_area((unsigned long)addr); + spin_lock(&vmap_area_lock); + va = __find_vmap_area((unsigned long)addr); if (va && va->flags & VM_VM_AREA) { struct vm_struct *vm = va->vm; - spin_lock(&vmap_area_lock); va->vm = NULL; va->flags &= ~VM_VM_AREA; - va->flags |= VM_LAZY_FREE; spin_unlock(&vmap_area_lock); kasan_free_shadow(vm); @@ -2152,6 +2161,8 @@ struct vm_struct *remove_vm_area(const void *addr) return vm; } + + spin_unlock(&vmap_area_lock); return NULL; } @@ -3431,6 +3442,22 @@ static void show_numa_info(struct seq_file *m, struct vm_struct *v) } } +static void show_purge_info(struct seq_file *m) +{ + struct llist_node *head; + struct vmap_area *va; + + head = READ_ONCE(vmap_purge_list.first); + if (head == NULL) + return; + + llist_for_each_entry(va, head, purge_list) { + seq_printf(m, "0x%pK-0x%pK %7ld unpurged vm_area\n", + (void *)va->va_start, (void *)va->va_end, + va->va_end - va->va_start); + } +} + static int s_show(struct seq_file *m, void *p) { struct vmap_area *va; @@ -3443,10 +3470,9 @@ static int s_show(struct seq_file *m, void *p) * behalf of vmap area is being tear down or vm_map_ram allocation. */ if (!(va->flags & VM_VM_AREA)) { - seq_printf(m, "0x%pK-0x%pK %7ld %s\n", + seq_printf(m, "0x%pK-0x%pK %7ld vm_map_ram\n", (void *)va->va_start, (void *)va->va_end, - va->va_end - va->va_start, - va->flags & VM_LAZY_FREE ? "unpurged vm_area" : "vm_map_ram"); + va->va_end - va->va_start); return 0; } @@ -3482,6 +3508,16 @@ static int s_show(struct seq_file *m, void *p) show_numa_info(m, v); seq_putc(m, '\n'); + + /* + * As a final step, dump "unpurged" areas. Note, + * that entire "/proc/vmallocinfo" output will not + * be address sorted, because the purge list is not + * sorted. + */ + if (list_is_last(&va->list, &vmap_area_list)) + show_purge_info(m); + return 0; }