| Message ID | 20240320110222.6564-7-shikemeng@huaweicloud.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Improve visibility of writeback | expand |
Hello, On Wed, Mar 20, 2024 at 07:02:22PM +0800, Kemeng Shi wrote: > We never use gdtc->dom set with GDTC_INIT_NO_WB, just remove unneeded > GDTC_INIT_NO_WB > > Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> ... > void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty) > { > - struct dirty_throttle_control gdtc = { GDTC_INIT_NO_WB }; > + struct dirty_throttle_control gdtc = { }; Even if it's currently not referenced, wouldn't it still be better to always guarantee that a dtc's dom is always initialized? I'm not sure what we get by removing this. Thanks.
on 3/20/2024 11:15 PM, Tejun Heo wrote: > Hello, > > On Wed, Mar 20, 2024 at 07:02:22PM +0800, Kemeng Shi wrote: >> We never use gdtc->dom set with GDTC_INIT_NO_WB, just remove unneeded >> GDTC_INIT_NO_WB >> >> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> > ... >> void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty) >> { >> - struct dirty_throttle_control gdtc = { GDTC_INIT_NO_WB }; >> + struct dirty_throttle_control gdtc = { }; > > Even if it's currently not referenced, wouldn't it still be better to always > guarantee that a dtc's dom is always initialized? I'm not sure what we get > by removing this. As we explicitly use GDTC_INIT_NO_WB to set global_wb_domain before calculating dirty limit with domain_dirty_limits, I intuitively think the dirty limit calculation in domain_dirty_limits is related to global_wb_domain when CONFIG_WRITEBACK_CGROUP is enabled while the truth is not. So this is a little confusing to me. Would it be acceptable to you that we keep useing GDTC_INIT_NO_WB but define GDTC_INIT_NO_WB to null fow now and redefine GDTC_INIT_NO_WB when some member of gdtc is really needed. Of couse I'm not insistent on this. Would like to hear you suggestion. Thanks! > > Thanks. >
On Thu, Mar 21, 2024 at 03:12:21PM +0800, Kemeng Shi wrote: > > > on 3/20/2024 11:15 PM, Tejun Heo wrote: > > Hello, > > > > On Wed, Mar 20, 2024 at 07:02:22PM +0800, Kemeng Shi wrote: > >> We never use gdtc->dom set with GDTC_INIT_NO_WB, just remove unneeded > >> GDTC_INIT_NO_WB > >> > >> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> > > ... > >> void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty) > >> { > >> - struct dirty_throttle_control gdtc = { GDTC_INIT_NO_WB }; > >> + struct dirty_throttle_control gdtc = { }; > > > > Even if it's currently not referenced, wouldn't it still be better to always > > guarantee that a dtc's dom is always initialized? I'm not sure what we get > > by removing this. > As we explicitly use GDTC_INIT_NO_WB to set global_wb_domain before > calculating dirty limit with domain_dirty_limits, I intuitively think the dirty > limit calculation in domain_dirty_limits is related to global_wb_domain when > CONFIG_WRITEBACK_CGROUP is enabled while the truth is not. So this is a little > confusing to me. > Would it be acceptable to you that we keep useing GDTC_INIT_NO_WB but > define GDTC_INIT_NO_WB to null fow now and redefine GDTC_INIT_NO_WB when some > member of gdtc is really needed. > Of couse I'm not insistent on this. Would like to hear you suggestion. Thanks! Ah, I see. In that case, the proposed change of removing GDTC_INIT_NO_WB looks good to me. Thanks.
On Wed 20-03-24 19:02:22, Kemeng Shi wrote: > We never use gdtc->dom set with GDTC_INIT_NO_WB, just remove unneeded > GDTC_INIT_NO_WB > > Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> Please no, this leaves a trap for the future. If anything, I'd teach GDTC_INIT() that 'wb' can be NULL and replace GDTC_INIT_NO_WB with GDTC_INIT(NULL). Honza > --- > mm/page-writeback.c | 7 ++----- > 1 file changed, 2 insertions(+), 5 deletions(-) > > diff --git a/mm/page-writeback.c b/mm/page-writeback.c > index 481b6bf34c21..09b2b0754cc5 100644 > --- a/mm/page-writeback.c > +++ b/mm/page-writeback.c > @@ -154,8 +154,6 @@ struct dirty_throttle_control { > .dom = &global_wb_domain, \ > .wb_completions = &(__wb)->completions > > -#define GDTC_INIT_NO_WB .dom = &global_wb_domain > - > #define MDTC_INIT(__wb, __gdtc) .wb = (__wb), \ > .dom = mem_cgroup_wb_domain(__wb), \ > .wb_completions = &(__wb)->memcg_completions, \ > @@ -210,7 +208,6 @@ static void wb_min_max_ratio(struct bdi_writeback *wb, > > #define GDTC_INIT(__wb) .wb = (__wb), \ > .wb_completions = &(__wb)->completions > -#define GDTC_INIT_NO_WB > #define MDTC_INIT(__wb, __gdtc) > > static bool mdtc_valid(struct dirty_throttle_control *dtc) > @@ -438,7 +435,7 @@ static void domain_dirty_limits(struct dirty_throttle_control *dtc) > */ > void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty) > { > - struct dirty_throttle_control gdtc = { GDTC_INIT_NO_WB }; > + struct dirty_throttle_control gdtc = { }; > > gdtc.avail = global_dirtyable_memory(); > domain_dirty_limits(&gdtc); > @@ -895,7 +892,7 @@ unsigned long wb_calc_thresh(struct bdi_writeback *wb, unsigned long thresh) > > unsigned long wb_calc_cg_thresh(struct bdi_writeback *wb) > { > - struct dirty_throttle_control gdtc = { GDTC_INIT_NO_WB }; > + struct dirty_throttle_control gdtc = { }; > struct dirty_throttle_control mdtc = { MDTC_INIT(wb, &gdtc) }; > unsigned long filepages, headroom, writeback; > > -- > 2.30.0 >
on 3/26/2024 4:26 AM, Tejun Heo wrote: > On Thu, Mar 21, 2024 at 03:12:21PM +0800, Kemeng Shi wrote: >> >> >> on 3/20/2024 11:15 PM, Tejun Heo wrote: >>> Hello, >>> >>> On Wed, Mar 20, 2024 at 07:02:22PM +0800, Kemeng Shi wrote: >>>> We never use gdtc->dom set with GDTC_INIT_NO_WB, just remove unneeded >>>> GDTC_INIT_NO_WB >>>> >>>> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> >>> ... >>>> void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty) >>>> { >>>> - struct dirty_throttle_control gdtc = { GDTC_INIT_NO_WB }; >>>> + struct dirty_throttle_control gdtc = { }; >>> >>> Even if it's currently not referenced, wouldn't it still be better to always >>> guarantee that a dtc's dom is always initialized? I'm not sure what we get >>> by removing this. >> As we explicitly use GDTC_INIT_NO_WB to set global_wb_domain before >> calculating dirty limit with domain_dirty_limits, I intuitively think the dirty >> limit calculation in domain_dirty_limits is related to global_wb_domain when >> CONFIG_WRITEBACK_CGROUP is enabled while the truth is not. So this is a little >> confusing to me. >> Would it be acceptable to you that we keep useing GDTC_INIT_NO_WB but >> define GDTC_INIT_NO_WB to null fow now and redefine GDTC_INIT_NO_WB when some >> member of gdtc is really needed. >> Of couse I'm not insistent on this. Would like to hear you suggestion. Thanks! > > Ah, I see. In that case, the proposed change of removing GDTC_INIT_NO_WB > looks good to me. Sure, will do it in next version. Thanks! > > Thanks. >
on 3/26/2024 8:35 PM, Jan Kara wrote: > On Wed 20-03-24 19:02:22, Kemeng Shi wrote: >> We never use gdtc->dom set with GDTC_INIT_NO_WB, just remove unneeded >> GDTC_INIT_NO_WB >> >> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> > > Please no, this leaves a trap for the future. If anything, I'd teach > GDTC_INIT() that 'wb' can be NULL and replace GDTC_INIT_NO_WB with > GDTC_INIT(NULL). Would it be acceptable to define GDTC_INIT_NO_WB to null for now as discussed in [1]. [1] https://lore.kernel.org/lkml/becdb16b-a318-ec05-61d2-d190541ae997@huaweicloud.com/ Thanks, Kemeng > > Honza > >> --- >> mm/page-writeback.c | 7 ++----- >> 1 file changed, 2 insertions(+), 5 deletions(-) >> >> diff --git a/mm/page-writeback.c b/mm/page-writeback.c >> index 481b6bf34c21..09b2b0754cc5 100644 >> --- a/mm/page-writeback.c >> +++ b/mm/page-writeback.c >> @@ -154,8 +154,6 @@ struct dirty_throttle_control { >> .dom = &global_wb_domain, \ >> .wb_completions = &(__wb)->completions >> >> -#define GDTC_INIT_NO_WB .dom = &global_wb_domain >> - >> #define MDTC_INIT(__wb, __gdtc) .wb = (__wb), \ >> .dom = mem_cgroup_wb_domain(__wb), \ >> .wb_completions = &(__wb)->memcg_completions, \ >> @@ -210,7 +208,6 @@ static void wb_min_max_ratio(struct bdi_writeback *wb, >> >> #define GDTC_INIT(__wb) .wb = (__wb), \ >> .wb_completions = &(__wb)->completions >> -#define GDTC_INIT_NO_WB >> #define MDTC_INIT(__wb, __gdtc) >> >> static bool mdtc_valid(struct dirty_throttle_control *dtc) >> @@ -438,7 +435,7 @@ static void domain_dirty_limits(struct dirty_throttle_control *dtc) >> */ >> void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty) >> { >> - struct dirty_throttle_control gdtc = { GDTC_INIT_NO_WB }; >> + struct dirty_throttle_control gdtc = { }; >> >> gdtc.avail = global_dirtyable_memory(); >> domain_dirty_limits(&gdtc); >> @@ -895,7 +892,7 @@ unsigned long wb_calc_thresh(struct bdi_writeback *wb, unsigned long thresh) >> >> unsigned long wb_calc_cg_thresh(struct bdi_writeback *wb) >> { >> - struct dirty_throttle_control gdtc = { GDTC_INIT_NO_WB }; >> + struct dirty_throttle_control gdtc = { }; >> struct dirty_throttle_control mdtc = { MDTC_INIT(wb, &gdtc) }; >> unsigned long filepages, headroom, writeback; >> >> -- >> 2.30.0 >>
On Thu 21-03-24 15:12:21, Kemeng Shi wrote: > > > on 3/20/2024 11:15 PM, Tejun Heo wrote: > > Hello, > > > > On Wed, Mar 20, 2024 at 07:02:22PM +0800, Kemeng Shi wrote: > >> We never use gdtc->dom set with GDTC_INIT_NO_WB, just remove unneeded > >> GDTC_INIT_NO_WB > >> > >> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> > > ... > >> void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty) > >> { > >> - struct dirty_throttle_control gdtc = { GDTC_INIT_NO_WB }; > >> + struct dirty_throttle_control gdtc = { }; > > > > Even if it's currently not referenced, wouldn't it still be better to always > > guarantee that a dtc's dom is always initialized? I'm not sure what we get > > by removing this. > As we explicitly use GDTC_INIT_NO_WB to set global_wb_domain before > calculating dirty limit with domain_dirty_limits, I intuitively think the > dirty limit calculation in domain_dirty_limits is related to > global_wb_domain when CONFIG_WRITEBACK_CGROUP is enabled while the truth > is not. So this is a little confusing to me. I'm not sure I understand your confusion. domain_dirty_limits() calculates the dirty limit (and background dirty limit) for the dirty_throttle_control passed in. If you pass dtc initialized with GDTC_INIT[_NO_WB], it will compute global dirty limits. If the dtc passed in is initialized with MDTC_INIT() it will compute cgroup specific dirty limits. Now because domain_dirty_limits() does not scale the limits based on each device throughput - that is done only later in __wb_calc_thresh() to avoid relatively expensive computations when we don't need them - and also because the effective dirty limit (dtc->dom->dirty_limit) is not updated by domain_dirty_limits(), domain_dirty_limits() does not need dtc->dom at all. But that is a technical detail of implementation and I don't want this technical detail to be relied on by even more code. What might have confused you is that GDTC_INIT_NO_WB is defined to be empty when CONFIG_CGROUP_WRITEBACK is disabled. But this is only because in that case dtc_dom() function unconditionally returns global_wb_domain so we don't bother with initializing (or even having) the 'dom' field anywhere. Now I agree this whole code is substantially confusing and complex and it would all deserve some serious thought how to make it more readable. But even after thinking about it again I don't think removing GDTC_INIT_NO_WB is the right way to go. Honza
on 3/27/2024 5:33 PM, Jan Kara wrote: > On Thu 21-03-24 15:12:21, Kemeng Shi wrote: >> >> >> on 3/20/2024 11:15 PM, Tejun Heo wrote: >>> Hello, >>> >>> On Wed, Mar 20, 2024 at 07:02:22PM +0800, Kemeng Shi wrote: >>>> We never use gdtc->dom set with GDTC_INIT_NO_WB, just remove unneeded >>>> GDTC_INIT_NO_WB >>>> >>>> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> >>> ... >>>> void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty) >>>> { >>>> - struct dirty_throttle_control gdtc = { GDTC_INIT_NO_WB }; >>>> + struct dirty_throttle_control gdtc = { }; >>> >>> Even if it's currently not referenced, wouldn't it still be better to always >>> guarantee that a dtc's dom is always initialized? I'm not sure what we get >>> by removing this. >> As we explicitly use GDTC_INIT_NO_WB to set global_wb_domain before >> calculating dirty limit with domain_dirty_limits, I intuitively think the >> dirty limit calculation in domain_dirty_limits is related to >> global_wb_domain when CONFIG_WRITEBACK_CGROUP is enabled while the truth >> is not. So this is a little confusing to me. > Hi Jan, > I'm not sure I understand your confusion. domain_dirty_limits() calculates > the dirty limit (and background dirty limit) for the dirty_throttle_control > passed in. If you pass dtc initialized with GDTC_INIT[_NO_WB], it will > compute global dirty limits. If the dtc passed in is initialized with > MDTC_INIT() it will compute cgroup specific dirty limits. No doubt about this. > > Now because domain_dirty_limits() does not scale the limits based on each > device throughput - that is done only later in __wb_calc_thresh() to avoid> relatively expensive computations when we don't need them - and also > because the effective dirty limit (dtc->dom->dirty_limit) is not updated by > domain_dirty_limits(), domain_dirty_limits() does not need dtc->dom at all. Acutally, here is the thing confusing me. For wb_calc_thresh, we always pass dtc initialized with a wb (GDTC_INIT(wb) or MDTC_INIT(wb,..). The dtc initialized with _NO_WB is only passed to domain_dirty_limits. However, The dom initialized by _NO_WB for domain_dirty_limits is not needed at all. > But that is a technical detail of implementation and I don't want this > technical detail to be relied on by even more code. Yes, I agree with this. So I wonder if it's acceptable to simply define GDTC_INIT_NO_WB to empty for now instead of remove defination of GDTC_INIT_NO_WB. When implementation of domain_dirty_limits() or any other low level function in future using GDTC_INIT(_NO_WB) changes to need dtc->domain, we re-define GDTC_INIT_NO_WB to proper value. As this only looks confusing to me. I will drop this one in next version if you still prefer to keep definatino of GDTC_INIT_NO_WB in the old way. Thanks, Kemeng > > What might have confused you is that GDTC_INIT_NO_WB is defined to be empty > when CONFIG_CGROUP_WRITEBACK is disabled. But this is only because in that > case dtc_dom() function unconditionally returns global_wb_domain so we > don't bother with initializing (or even having) the 'dom' field anywhere. > > Now I agree this whole code is substantially confusing and complex and it > would all deserve some serious thought how to make it more readable. But > even after thinking about it again I don't think removing GDTC_INIT_NO_WB is > the right way to go. > > Honza >
On Thu 28-03-24 09:49:59, Kemeng Shi wrote: > on 3/27/2024 5:33 PM, Jan Kara wrote: > > On Thu 21-03-24 15:12:21, Kemeng Shi wrote: > >> > >> > >> on 3/20/2024 11:15 PM, Tejun Heo wrote: > >>> Hello, > >>> > >>> On Wed, Mar 20, 2024 at 07:02:22PM +0800, Kemeng Shi wrote: > >>>> We never use gdtc->dom set with GDTC_INIT_NO_WB, just remove unneeded > >>>> GDTC_INIT_NO_WB > >>>> > >>>> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> > >>> ... > >>>> void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty) > >>>> { > >>>> - struct dirty_throttle_control gdtc = { GDTC_INIT_NO_WB }; > >>>> + struct dirty_throttle_control gdtc = { }; > >>> > >>> Even if it's currently not referenced, wouldn't it still be better to always > >>> guarantee that a dtc's dom is always initialized? I'm not sure what we get > >>> by removing this. > >> As we explicitly use GDTC_INIT_NO_WB to set global_wb_domain before > >> calculating dirty limit with domain_dirty_limits, I intuitively think the > >> dirty limit calculation in domain_dirty_limits is related to > >> global_wb_domain when CONFIG_WRITEBACK_CGROUP is enabled while the truth > >> is not. So this is a little confusing to me. > > > Hi Jan, > > I'm not sure I understand your confusion. domain_dirty_limits() calculates > > the dirty limit (and background dirty limit) for the dirty_throttle_control > > passed in. If you pass dtc initialized with GDTC_INIT[_NO_WB], it will > > compute global dirty limits. If the dtc passed in is initialized with > > MDTC_INIT() it will compute cgroup specific dirty limits. > No doubt about this. > > > > Now because domain_dirty_limits() does not scale the limits based on each > > device throughput - that is done only later in __wb_calc_thresh() to avoid> relatively expensive computations when we don't need them - and also > > because the effective dirty limit (dtc->dom->dirty_limit) is not updated by > > domain_dirty_limits(), domain_dirty_limits() does not need dtc->dom at all. > Acutally, here is the thing confusing me. For wb_calc_thresh, we always pass > dtc initialized with a wb (GDTC_INIT(wb) or MDTC_INIT(wb,..). The dtc > initialized with _NO_WB is only passed to domain_dirty_limits. However, The > dom initialized by _NO_WB for domain_dirty_limits is not needed at all. > > But that is a technical detail of implementation and I don't want this > > technical detail to be relied on by even more code. > Yes, I agree with this. So I wonder if it's acceptable to simply define > GDTC_INIT_NO_WB to empty for now instead of remove defination of > GDTC_INIT_NO_WB. When implementation of domain_dirty_limits() or any > other low level function in future using GDTC_INIT(_NO_WB) changes to > need dtc->domain, we re-define GDTC_INIT_NO_WB to proper value. > As this only looks confusing to me. I will drop this one in next version > if you still prefer to keep definatino of GDTC_INIT_NO_WB in the old way. Yeah, please keep the code as is for now. I agree this needs some cleanups but what you suggest is IMHO not an improvement. Honza
on 4/2/2024 9:53 PM, Jan Kara wrote: > On Thu 28-03-24 09:49:59, Kemeng Shi wrote: >> on 3/27/2024 5:33 PM, Jan Kara wrote: >>> On Thu 21-03-24 15:12:21, Kemeng Shi wrote: >>>> >>>> >>>> on 3/20/2024 11:15 PM, Tejun Heo wrote: >>>>> Hello, >>>>> >>>>> On Wed, Mar 20, 2024 at 07:02:22PM +0800, Kemeng Shi wrote: >>>>>> We never use gdtc->dom set with GDTC_INIT_NO_WB, just remove unneeded >>>>>> GDTC_INIT_NO_WB >>>>>> >>>>>> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> >>>>> ... >>>>>> void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty) >>>>>> { >>>>>> - struct dirty_throttle_control gdtc = { GDTC_INIT_NO_WB }; >>>>>> + struct dirty_throttle_control gdtc = { }; >>>>> >>>>> Even if it's currently not referenced, wouldn't it still be better to always >>>>> guarantee that a dtc's dom is always initialized? I'm not sure what we get >>>>> by removing this. >>>> As we explicitly use GDTC_INIT_NO_WB to set global_wb_domain before >>>> calculating dirty limit with domain_dirty_limits, I intuitively think the >>>> dirty limit calculation in domain_dirty_limits is related to >>>> global_wb_domain when CONFIG_WRITEBACK_CGROUP is enabled while the truth >>>> is not. So this is a little confusing to me. >>> >> Hi Jan, >>> I'm not sure I understand your confusion. domain_dirty_limits() calculates >>> the dirty limit (and background dirty limit) for the dirty_throttle_control >>> passed in. If you pass dtc initialized with GDTC_INIT[_NO_WB], it will >>> compute global dirty limits. If the dtc passed in is initialized with >>> MDTC_INIT() it will compute cgroup specific dirty limits. >> No doubt about this. >>> >>> Now because domain_dirty_limits() does not scale the limits based on each >>> device throughput - that is done only later in __wb_calc_thresh() to avoid> relatively expensive computations when we don't need them - and also >>> because the effective dirty limit (dtc->dom->dirty_limit) is not updated by >>> domain_dirty_limits(), domain_dirty_limits() does not need dtc->dom at all. >> Acutally, here is the thing confusing me. For wb_calc_thresh, we always pass >> dtc initialized with a wb (GDTC_INIT(wb) or MDTC_INIT(wb,..). The dtc >> initialized with _NO_WB is only passed to domain_dirty_limits. However, The >> dom initialized by _NO_WB for domain_dirty_limits is not needed at all. >>> But that is a technical detail of implementation and I don't want this >>> technical detail to be relied on by even more code. >> Yes, I agree with this. So I wonder if it's acceptable to simply define >> GDTC_INIT_NO_WB to empty for now instead of remove defination of >> GDTC_INIT_NO_WB. When implementation of domain_dirty_limits() or any >> other low level function in future using GDTC_INIT(_NO_WB) changes to >> need dtc->domain, we re-define GDTC_INIT_NO_WB to proper value. >> As this only looks confusing to me. I will drop this one in next version >> if you still prefer to keep definatino of GDTC_INIT_NO_WB in the old way. > > Yeah, please keep the code as is for now. I agree this needs some cleanups > but what you suggest is IMHO not an improvement. Sure, will drop this in next version. Thanks, Kemeng > > Honza >
diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 481b6bf34c21..09b2b0754cc5 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -154,8 +154,6 @@ struct dirty_throttle_control { .dom = &global_wb_domain, \ .wb_completions = &(__wb)->completions -#define GDTC_INIT_NO_WB .dom = &global_wb_domain - #define MDTC_INIT(__wb, __gdtc) .wb = (__wb), \ .dom = mem_cgroup_wb_domain(__wb), \ .wb_completions = &(__wb)->memcg_completions, \ @@ -210,7 +208,6 @@ static void wb_min_max_ratio(struct bdi_writeback *wb, #define GDTC_INIT(__wb) .wb = (__wb), \ .wb_completions = &(__wb)->completions -#define GDTC_INIT_NO_WB #define MDTC_INIT(__wb, __gdtc) static bool mdtc_valid(struct dirty_throttle_control *dtc) @@ -438,7 +435,7 @@ static void domain_dirty_limits(struct dirty_throttle_control *dtc) */ void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty) { - struct dirty_throttle_control gdtc = { GDTC_INIT_NO_WB }; + struct dirty_throttle_control gdtc = { }; gdtc.avail = global_dirtyable_memory(); domain_dirty_limits(&gdtc); @@ -895,7 +892,7 @@ unsigned long wb_calc_thresh(struct bdi_writeback *wb, unsigned long thresh) unsigned long wb_calc_cg_thresh(struct bdi_writeback *wb) { - struct dirty_throttle_control gdtc = { GDTC_INIT_NO_WB }; + struct dirty_throttle_control gdtc = { }; struct dirty_throttle_control mdtc = { MDTC_INIT(wb, &gdtc) }; unsigned long filepages, headroom, writeback;
We never use gdtc->dom set with GDTC_INIT_NO_WB, just remove unneeded GDTC_INIT_NO_WB Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> --- mm/page-writeback.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-)