lkml.org 
[lkml]   [2016]   [Oct]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [patch v2] drivers/zram: Don't disable preemption in zcomp_stream_get/put()
On 2016-10-19 17:56:30 [+0200], Mike Galbraith wrote:
> In v4.7, the driver switched to percpu compression streams, disabling
> preemption vai get/put_cpu_ptr(). Use a local lock instead for RT.
> We also have to fix an RT lock order issue in zram_decompress_page()
> such that zs_map_object() nests inside of zcomp_stream_put() as it
> does in zram_bvec_write().

good. I almost had it myself. So let me get that one. And your previous
one (the spinlock replacement) looks also reasonable. With this hunk

@@ -313,6 +314,7 @@ struct mapping_area {
#endif
char *vm_addr; /* address of kmap_atomic()'ed pages */
enum zs_mapmode vm_mm; /* mapping mode */
+ spinlock_t ma_lock;
};

#ifdef CONFIG_COMPACTION
@@ -1489,6 +1491,7 @@ void *zs_map_object(struct zs_pool *pool, unsigned long handle,
off = (class->size * obj_idx) & ~PAGE_MASK;

area = per_cpu_ptr(&zs_map_area, get_cpu_light());
+ spin_lock(&area->ma_lock);
area->vm_mm = mm;
if (off + class->size <= PAGE_SIZE) {
/* this object is contained entirely within a page */
@@ -1542,6 +1545,7 @@ void zs_unmap_object(struct zs_pool *pool, unsigned long handle)

__zs_unmap_object(area, pages, off, class->size);
}
+ spin_unlock(&area->ma_lock);
put_cpu_light();

migrate_read_unlock(zspage);

I don't see this anymore:

|gcc: internal compiler error: Killed (program cc1)
|Please submit a full bug report,
|with preprocessed source if appropriate.
|See <file:///usr/share/doc/gcc-6/README.Bugs> for instructions.
|Makefile:134: recipe for target 'servconf.o' failed
|make: *** [servconf.o] Error 4
|make: *** Waiting for unfinished jobs....
|
|
|loginrec.c:1722:1: internal compiler error: Bus error
| }
| ^

only
|gcc: internal compiler error: Killed (program cc1)

which is expected.

> Signed-off-by: Mike Galbraith <umgwanakikbuti@gmail.com>

Sebastian

\
 
 \ /
  Last update: 2016-10-19 18:55    [W:0.116 / U:3.848 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site