* [PATCH] reiserfs: use __GFP_NOFAIL instead of yield and retry loop for allocation
@ 2006-01-13 7:33 Pekka J Enberg
2006-01-13 7:42 ` Andrew Morton
0 siblings, 1 reply; 5+ messages in thread
From: Pekka J Enberg @ 2006-01-13 7:33 UTC (permalink / raw)
To: akpm; +Cc: linux-kernel, reiserfs-dev
From: Pekka Enberg <penberg@cs.helsinki.fi>
This patch replaces yield and retry loop with __GFP_NOFAIL in
alloc_journal_list(). Compile-tested only.
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
---
fs/reiserfs/journal.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)
Index: 2.6/fs/reiserfs/journal.c
===================================================================
--- 2.6.orig/fs/reiserfs/journal.c
+++ 2.6/fs/reiserfs/journal.c
@@ -2446,12 +2446,8 @@ static int journal_read(struct super_blo
static struct reiserfs_journal_list *alloc_journal_list(struct super_block *s)
{
struct reiserfs_journal_list *jl;
- retry:
- jl = kzalloc(sizeof(struct reiserfs_journal_list), GFP_NOFS);
- if (!jl) {
- yield();
- goto retry;
- }
+ jl = kzalloc(sizeof(struct reiserfs_journal_list),
+ GFP_NOFS | __GFP_NOFAIL);
INIT_LIST_HEAD(&jl->j_list);
INIT_LIST_HEAD(&jl->j_working_list);
INIT_LIST_HEAD(&jl->j_tail_bh_list);
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] reiserfs: use __GFP_NOFAIL instead of yield and retry loop for allocation
2006-01-13 7:33 [PATCH] reiserfs: use __GFP_NOFAIL instead of yield and retry loop for allocation Pekka J Enberg
@ 2006-01-13 7:42 ` Andrew Morton
2006-01-13 7:46 ` Pekka J Enberg
0 siblings, 1 reply; 5+ messages in thread
From: Andrew Morton @ 2006-01-13 7:42 UTC (permalink / raw)
To: Pekka J Enberg; +Cc: linux-kernel, reiserfs-dev
Pekka J Enberg <penberg@cs.Helsinki.FI> wrote:
>
> - retry:
> - jl = kzalloc(sizeof(struct reiserfs_journal_list), GFP_NOFS);
> - if (!jl) {
> - yield();
> - goto retry;
> - }
> + jl = kzalloc(sizeof(struct reiserfs_journal_list),
> + GFP_NOFS | __GFP_NOFAIL);
yup, that's what __GFP_NOFAIL is for: to consolidate and identify all those
places which want to lock up when we're short of memory... They all need
fixing, really.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] reiserfs: use __GFP_NOFAIL instead of yield and retry loop for allocation
2006-01-13 7:42 ` Andrew Morton
@ 2006-01-13 7:46 ` Pekka J Enberg
2006-01-13 7:55 ` Andrew Morton
0 siblings, 1 reply; 5+ messages in thread
From: Pekka J Enberg @ 2006-01-13 7:46 UTC (permalink / raw)
To: Andrew Morton; +Cc: linux-kernel, reiserfs-dev
Hi,
Pekka J Enberg <penberg@cs.Helsinki.FI> wrote:
> >
> > - retry:
> > - jl = kzalloc(sizeof(struct reiserfs_journal_list), GFP_NOFS);
> > - if (!jl) {
> > - yield();
> > - goto retry;
> > - }
> > + jl = kzalloc(sizeof(struct reiserfs_journal_list),
> > + GFP_NOFS | __GFP_NOFAIL);
On Thu, 12 Jan 2006, Andrew Morton wrote:
> yup, that's what __GFP_NOFAIL is for: to consolidate and identify all those
> places which want to lock up when we're short of memory... They all need
> fixing, really.
Out of curiosity, are there any potential problems with combining GFP_NOFS
and __GFP_NOFAIL? Can we really guarantee to give out memory if we're not
allowed to page out?
Pekka
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] reiserfs: use __GFP_NOFAIL instead of yield and retry loop for allocation
2006-01-13 7:46 ` Pekka J Enberg
@ 2006-01-13 7:55 ` Andrew Morton
2006-01-13 21:44 ` Hans Reiser
0 siblings, 1 reply; 5+ messages in thread
From: Andrew Morton @ 2006-01-13 7:55 UTC (permalink / raw)
To: Pekka J Enberg; +Cc: linux-kernel, reiserfs-dev
Pekka J Enberg <penberg@cs.Helsinki.FI> wrote:
>
> Hi,
>
> Pekka J Enberg <penberg@cs.Helsinki.FI> wrote:
> > >
> > > - retry:
> > > - jl = kzalloc(sizeof(struct reiserfs_journal_list), GFP_NOFS);
> > > - if (!jl) {
> > > - yield();
> > > - goto retry;
> > > - }
> > > + jl = kzalloc(sizeof(struct reiserfs_journal_list),
> > > + GFP_NOFS | __GFP_NOFAIL);
>
> On Thu, 12 Jan 2006, Andrew Morton wrote:
> > yup, that's what __GFP_NOFAIL is for: to consolidate and identify all those
> > places which want to lock up when we're short of memory... They all need
> > fixing, really.
>
> Out of curiosity, are there any potential problems with combining GFP_NOFS
> and __GFP_NOFAIL? Can we really guarantee to give out memory if we're not
> allowed to page out?
>
GFP_NOFS increases the risk (relative to GFP_KERNEL) because page reclaim
can do less things than GFP_KERNEL to free memory.
GFP_NOFS allocations can still perform swapspace writes, however. GFP_NOIO
cannot even do that.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] reiserfs: use __GFP_NOFAIL instead of yield and retry loop for allocation
2006-01-13 7:55 ` Andrew Morton
@ 2006-01-13 21:44 ` Hans Reiser
0 siblings, 0 replies; 5+ messages in thread
From: Hans Reiser @ 2006-01-13 21:44 UTC (permalink / raw)
To: Andrew Morton; +Cc: Pekka J Enberg, linux-kernel, reiserfs-dev
Do you guys think you could write some nice long comments on these flags
regarding what they mean and the policies for using them?
I gotta tell you, lots of people end up just guessing as best as they can.
Hans
Andrew Morton wrote:
>Pekka J Enberg <penberg@cs.Helsinki.FI> wrote:
>
>
>>Hi,
>>
>>Pekka J Enberg <penberg@cs.Helsinki.FI> wrote:
>>
>>
>>>> - retry:
>>>> - jl = kzalloc(sizeof(struct reiserfs_journal_list), GFP_NOFS);
>>>> - if (!jl) {
>>>> - yield();
>>>> - goto retry;
>>>> - }
>>>> + jl = kzalloc(sizeof(struct reiserfs_journal_list),
>>>> + GFP_NOFS | __GFP_NOFAIL);
>>>>
>>>>
>>On Thu, 12 Jan 2006, Andrew Morton wrote:
>>
>>
>>>yup, that's what __GFP_NOFAIL is for: to consolidate and identify all those
>>>places which want to lock up when we're short of memory... They all need
>>>fixing, really.
>>>
>>>
>>Out of curiosity, are there any potential problems with combining GFP_NOFS
>>and __GFP_NOFAIL? Can we really guarantee to give out memory if we're not
>>allowed to page out?
>>
>>
>>
>
>GFP_NOFS increases the risk (relative to GFP_KERNEL) because page reclaim
>can do less things than GFP_KERNEL to free memory.
>
>GFP_NOFS allocations can still perform swapspace writes, however. GFP_NOIO
>cannot even do that.
>
>
>
>
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2006-01-13 21:44 UTC | newest]
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2006-01-13 7:33 [PATCH] reiserfs: use __GFP_NOFAIL instead of yield and retry loop for allocation Pekka J Enberg
2006-01-13 7:42 ` Andrew Morton
2006-01-13 7:46 ` Pekka J Enberg
2006-01-13 7:55 ` Andrew Morton
2006-01-13 21:44 ` Hans Reiser
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