Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 232ea4d6 authored by Andrew Morton's avatar Andrew Morton Committed by Linus Torvalds
Browse files

[PATCH] throttle_vm_writeout(): don't loop on GFP_NOFS and GFP_NOIO allocations 



throttle_vm_writeout() is designed to wait for the dirty levels to subside.
But if the caller holds IO or FS locks, we might be holding up that writeout.

So change it to take a single nap to give other devices a chance to clean some
memory, then return.

Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent b1a316f6

include/linux/writeback.h

+1 −1
Original line number Diff line number Diff line
@@ -84,7 +84,7 @@ static inline void wait_on_inode(struct inode *inode) 
int wakeup_pdflush(long nr_pages);

void laptop_io_completion(void);

void laptop_sync_completion(void);

void throttle_vm_writeout(void);

void throttle_vm_writeout(gfp_t gfp_mask);



/* These are exported to sysctl. */

extern int dirty_background_ratio;

mm/page-writeback.c

+11 −2
Original line number Diff line number Diff line
@@ -296,11 +296,21 @@ void balance_dirty_pages_ratelimited_nr(struct address_space *mapping, 
}

EXPORT_SYMBOL(balance_dirty_pages_ratelimited_nr);



void throttle_vm_writeout(void)

void throttle_vm_writeout(gfp_t gfp_mask)

{

	long background_thresh;

	long dirty_thresh;



	if ((gfp_mask & (__GFP_FS|__GFP_IO)) != (__GFP_FS|__GFP_IO)) {

		/*

		 * The caller might hold locks which can prevent IO completion

		 * or progress in the filesystem.  So we cannot just sit here

		 * waiting for IO to complete.

		 */

		congestion_wait(WRITE, HZ/10);

		return;

	}



        for ( ; ; ) {

		get_dirty_limits(&background_thresh, &dirty_thresh, NULL);
@@ -317,7 +327,6 @@ void throttle_vm_writeout(void) 
        }

}





/*

 * writeback at least _min_pages, and keep writing until the amount of dirty

 * memory is less than the background threshold, or until we're all clean.

mm/vmscan.c

+1 −1
Original line number Diff line number Diff line
@@ -952,7 +952,7 @@ static unsigned long shrink_zone(int priority, struct zone *zone, 
		}

	}



	throttle_vm_writeout();

	throttle_vm_writeout(sc->gfp_mask);



	atomic_dec(&zone->reclaim_in_progress);

	return nr_reclaimed;