From: Minchan Kim <minchan@xxxxxxxxxx> In cloning the vroot tree during a fork, we have to allocate memory while hold the vroot lock. This is problematic, as the memory allocation can trigger reclaim, which might require grabbing a vroot lock in order to find purgable pages. Thus this patch introduces GFP_NO_VRANGE which will allow us to avoid having a allocation for vrange to trigger any volatile range purging. XXX: We're not yet using this flag in the later purge paths, so we still get the lockdep warnings. Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Android Kernel Team <kernel-team@xxxxxxxxxxx> Cc: Robert Love <rlove@xxxxxxxxxx> Cc: Mel Gorman <mel@xxxxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Cc: Dave Hansen <dave@xxxxxxxxxxxxxxxxxx> Cc: Rik van Riel <riel@xxxxxxxxxx> Cc: Dmitry Adamushko <dmitry.adamushko@xxxxxxxxx> Cc: Dave Chinner <david@xxxxxxxxxxxxx> Cc: Neil Brown <neilb@xxxxxxx> Cc: Andrea Righi <andrea@xxxxxxxxxxxxxxx> Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx> Cc: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx> Cc: Mike Hommey <mh@xxxxxxxxxxxx> Cc: Taras Glek <tglek@xxxxxxxxxxx> Cc: Dhaval Giani <dgiani@xxxxxxxxxxx> Cc: Jan Kara <jack@xxxxxxx> Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxx> Cc: Michel Lespinasse <walken@xxxxxxxxxx> Cc: Minchan Kim <minchan@xxxxxxxxxx> Cc: linux-mm@xxxxxxxxx <linux-mm@xxxxxxxxx> Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx> [jstultz: Split out from a different patch, created new commit message] Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx> --- include/linux/gfp.h | 7 +++++-- mm/vrange.c | 2 +- 2 files changed, 6 insertions(+), 3 deletions(-) diff --git a/include/linux/gfp.h b/include/linux/gfp.h index 0f615eb..fa52199 100644 --- a/include/linux/gfp.h +++ b/include/linux/gfp.h @@ -35,6 +35,7 @@ struct vm_area_struct; #define ___GFP_NO_KSWAPD 0x400000u #define ___GFP_OTHER_NODE 0x800000u #define ___GFP_WRITE 0x1000000u +#define ___GFP_NO_VRANGE 0x2000000u /* If the above are modified, __GFP_BITS_SHIFT may need updating */ /* @@ -70,6 +71,7 @@ struct vm_area_struct; #define __GFP_HIGH ((__force gfp_t)___GFP_HIGH) /* Should access emergency pools? */ #define __GFP_IO ((__force gfp_t)___GFP_IO) /* Can start physical IO? */ #define __GFP_FS ((__force gfp_t)___GFP_FS) /* Can call down to low-level FS? */ +#define __GFP_NO_VRANGE ((__force gfp_t)___GFP_NO_VRANGE) /* Can't reclaim volatile pages */ #define __GFP_COLD ((__force gfp_t)___GFP_COLD) /* Cache-cold page required */ #define __GFP_NOWARN ((__force gfp_t)___GFP_NOWARN) /* Suppress page allocation failure warning */ #define __GFP_REPEAT ((__force gfp_t)___GFP_REPEAT) /* See above */ @@ -99,7 +101,7 @@ struct vm_area_struct; */ #define __GFP_NOTRACK_FALSE_POSITIVE (__GFP_NOTRACK) -#define __GFP_BITS_SHIFT 25 /* Room for N __GFP_FOO bits */ +#define __GFP_BITS_SHIFT 26 /* Room for N __GFP_FOO bits */ #define __GFP_BITS_MASK ((__force gfp_t)((1 << __GFP_BITS_SHIFT) - 1)) /* This equals 0, but use constants in case they ever change */ @@ -134,7 +136,8 @@ struct vm_area_struct; /* Control page allocator reclaim behavior */ #define GFP_RECLAIM_MASK (__GFP_WAIT|__GFP_HIGH|__GFP_IO|__GFP_FS|\ __GFP_NOWARN|__GFP_REPEAT|__GFP_NOFAIL|\ - __GFP_NORETRY|__GFP_MEMALLOC|__GFP_NOMEMALLOC) + __GFP_NORETRY|__GFP_MEMALLOC|__GFP_NOMEMALLOC|\ + __GFP_NO_VRANGE) /* Control slab gfp mask during early boot */ #define GFP_BOOT_MASK (__GFP_BITS_MASK & ~(__GFP_WAIT|__GFP_IO|__GFP_FS)) diff --git a/mm/vrange.c b/mm/vrange.c index f3c2465..5278939 100644 --- a/mm/vrange.c +++ b/mm/vrange.c @@ -204,7 +204,7 @@ int vrange_fork(struct mm_struct *new_mm, struct mm_struct *old_mm) range = vrange_entry(next); next = rb_next(next); - new_range = __vrange_alloc(GFP_KERNEL); + new_range = __vrange_alloc(GFP_KERNEL|__GFP_NO_VRANGE); if (!new_range) goto fail; __vrange_set(new_range, range->node.start, -- 1.8.1.2 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>