* Re: [PATCH v1] include/linux/gfp.h: getting rid of GFP_ZONE_TABLE/BAD [not found] <1525968625-40825-1-git-send-email-yehs1@lenovo.com> @ 2018-05-10 16:30 ` Matthew Wilcox 2018-05-11 3:24 ` [External] " Huaisheng HS1 Ye 0 siblings, 1 reply; 7+ messages in thread From: Matthew Wilcox @ 2018-05-10 16:30 UTC (permalink / raw) To: Huaisheng Ye Cc: akpm, linux-mm, mhocko, vbabka, mgorman, alexander.levin, colyli, chengnt, linux-kernel On Fri, May 11, 2018 at 12:10:25AM +0800, Huaisheng Ye wrote: > -#define __GFP_DMA ((__force gfp_t)___GFP_DMA) > -#define __GFP_HIGHMEM ((__force gfp_t)___GFP_HIGHMEM) > -#define __GFP_DMA32 ((__force gfp_t)___GFP_DMA32) > +#define __GFP_DMA ((__force gfp_t)OPT_ZONE_DMA ^ ZONE_NORMAL) > +#define __GFP_HIGHMEM ((__force gfp_t)ZONE_MOVABLE ^ ZONE_NORMAL) > +#define __GFP_DMA32 ((__force gfp_t)OPT_ZONE_DMA32 ^ ZONE_NORMAL) No, you've made gfp_zone even more complex than it already is. If you can't use OPT_ZONE_HIGHMEM here, then this is a waste of time. > static inline enum zone_type gfp_zone(gfp_t flags) > { > enum zone_type z; > - int bit = (__force int) (flags & GFP_ZONEMASK); > + z = ((__force unsigned int)flags & ___GFP_ZONE_MASK) ^ ZONE_NORMAL; > + > + if (z > OPT_ZONE_HIGHMEM) > + z = OPT_ZONE_HIGHMEM + > + !!((__force unsigned int)flags & ___GFP_MOVABLE); > > - z = (GFP_ZONE_TABLE >> (bit * GFP_ZONES_SHIFT)) & > - ((1 << GFP_ZONES_SHIFT) - 1); > - VM_BUG_ON((GFP_ZONE_BAD >> bit) & 1); > + VM_BUG_ON(z > ZONE_MOVABLE); > return z; > } ^ permalink raw reply [flat|nested] 7+ messages in thread
* RE: [External] Re: [PATCH v1] include/linux/gfp.h: getting rid of GFP_ZONE_TABLE/BAD 2018-05-10 16:30 ` [PATCH v1] include/linux/gfp.h: getting rid of GFP_ZONE_TABLE/BAD Matthew Wilcox @ 2018-05-11 3:24 ` Huaisheng HS1 Ye 2018-05-11 13:26 ` Matthew Wilcox 0 siblings, 1 reply; 7+ messages in thread From: Huaisheng HS1 Ye @ 2018-05-11 3:24 UTC (permalink / raw) To: Matthew Wilcox Cc: akpm, linux-mm, mhocko, vbabka, mgorman, alexander.levin, colyli, NingTing Cheng, linux-kernel > From: owner-linux-mm@kvack.org [mailto:owner-linux-mm@kvack.org] On Behalf Of Matthew > Wilcox > On Fri, May 11, 2018 at 12:10:25AM +0800, Huaisheng Ye wrote: > > -#define __GFP_DMA ((__force gfp_t)___GFP_DMA) > > -#define __GFP_HIGHMEM ((__force gfp_t)___GFP_HIGHMEM) > > -#define __GFP_DMA32 ((__force gfp_t)___GFP_DMA32) > > +#define __GFP_DMA ((__force gfp_t)OPT_ZONE_DMA ^ ZONE_NORMAL) > > +#define __GFP_HIGHMEM ((__force gfp_t)ZONE_MOVABLE ^ ZONE_NORMAL) > > +#define __GFP_DMA32 ((__force gfp_t)OPT_ZONE_DMA32 ^ ZONE_NORMAL) > > No, you've made gfp_zone even more complex than it already is. > If you can't use OPT_ZONE_HIGHMEM here, then this is a waste of time. > Dear Matthew, The reason why I don't use OPT_ZONE_HIGHMEM for __GFP_HIGHMEM directly is that, for x86_64 platform there is no CONFIG_HIGHMEM, so OPT_ZONE_HIGHMEM shall always be equal to ZONE_NORMAL. For gfp_zone it is impossible to distinguish the meaning of lowest 3 bits in flags. How can gfp_zone to understand it comes from OPT_ZONE_HIGHMEM or ZONE_NORMAL? And the most pained thing is that, if __GFP_HIGHMEM with movable flag enabled, it means that ZONE_MOVABLE shall be returned. That is different from ZONE_DMA, ZONE_DMA32 and ZONE_NORMAL. I was thinking... Whether it is possible to use other judgement condition to decide OPT_ZONE_HIGHMEM or ZONE_MOVABLE shall be returned from gfp_zone. Sincerely, Huaisheng Ye > > static inline enum zone_type gfp_zone(gfp_t flags) > > { > > enum zone_type z; > > - int bit = (__force int) (flags & GFP_ZONEMASK); > > + z = ((__force unsigned int)flags & ___GFP_ZONE_MASK) ^ ZONE_NORMAL; > > + > > + if (z > OPT_ZONE_HIGHMEM) > > + z = OPT_ZONE_HIGHMEM + > > + !!((__force unsigned int)flags & ___GFP_MOVABLE); > > > > - z = (GFP_ZONE_TABLE >> (bit * GFP_ZONES_SHIFT)) & > > - ((1 << GFP_ZONES_SHIFT) - 1); > > - VM_BUG_ON((GFP_ZONE_BAD >> bit) & 1); > > + VM_BUG_ON(z > ZONE_MOVABLE); > > return z; > > } ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [External] Re: [PATCH v1] include/linux/gfp.h: getting rid of GFP_ZONE_TABLE/BAD 2018-05-11 3:24 ` [External] " Huaisheng HS1 Ye @ 2018-05-11 13:26 ` Matthew Wilcox 2018-05-12 11:35 ` Huaisheng HS1 Ye 2018-05-18 3:03 ` Huaisheng HS1 Ye 0 siblings, 2 replies; 7+ messages in thread From: Matthew Wilcox @ 2018-05-11 13:26 UTC (permalink / raw) To: Huaisheng HS1 Ye Cc: akpm, linux-mm, mhocko, vbabka, mgorman, alexander.levin, colyli, NingTing Cheng, linux-kernel On Fri, May 11, 2018 at 03:24:34AM +0000, Huaisheng HS1 Ye wrote: > > From: owner-linux-mm@kvack.org [mailto:owner-linux-mm@kvack.org] On Behalf Of Matthew > > Wilcox > > On Fri, May 11, 2018 at 12:10:25AM +0800, Huaisheng Ye wrote: > > > -#define __GFP_DMA ((__force gfp_t)___GFP_DMA) > > > -#define __GFP_HIGHMEM ((__force gfp_t)___GFP_HIGHMEM) > > > -#define __GFP_DMA32 ((__force gfp_t)___GFP_DMA32) > > > +#define __GFP_DMA ((__force gfp_t)OPT_ZONE_DMA ^ ZONE_NORMAL) > > > +#define __GFP_HIGHMEM ((__force gfp_t)ZONE_MOVABLE ^ ZONE_NORMAL) > > > +#define __GFP_DMA32 ((__force gfp_t)OPT_ZONE_DMA32 ^ ZONE_NORMAL) > > > > No, you've made gfp_zone even more complex than it already is. > > If you can't use OPT_ZONE_HIGHMEM here, then this is a waste of time. > > > Dear Matthew, > > The reason why I don't use OPT_ZONE_HIGHMEM for __GFP_HIGHMEM directly is that, for x86_64 platform there is no CONFIG_HIGHMEM, so OPT_ZONE_HIGHMEM shall always be equal to ZONE_NORMAL. Right. On 64-bit platforms, if somebody asks for HIGHMEM, they should get NORMAL pages. > For gfp_zone it is impossible to distinguish the meaning of lowest 3 bits in flags. How can gfp_zone to understand it comes from OPT_ZONE_HIGHMEM or ZONE_NORMAL? > And the most pained thing is that, if __GFP_HIGHMEM with movable flag enabled, it means that ZONE_MOVABLE shall be returned. > That is different from ZONE_DMA, ZONE_DMA32 and ZONE_NORMAL. The point of this exercise is to actually encode the zone number in the bottom bits of the GFP flags instead of something which has to be interpreted into a zone number. When somebody sets __GFP_MOVABLE, they should also be setting ZONE_MOVABLE: -#define __GFP_MOVABLE ((__force gfp_t)___GFP_MOVABLE) /* ZONE_MOVABLE allowed */ +#define __GFP_MOVABLE ((__force gfp_t)(___GFP_MOVABLE | (ZONE_MOVABLE ^ ZONE_NORMAL))) One thing that does need to change is: -#define GFP_HIGHUSER_MOVABLE (GFP_HIGHUSER | __GFP_MOVABLE) +#define GFP_HIGHUSER_MOVABLE (GFP_USER | __GFP_MOVABLE) otherwise we'll be OR'ing ZONE_MOVABLE and ZONE_HIGHMEM together. > I was thinking... > Whether it is possible to use other judgement condition to decide OPT_ZONE_HIGHMEM or ZONE_MOVABLE shall be returned from gfp_zone. > > Sincerely, > Huaisheng Ye > > > > > static inline enum zone_type gfp_zone(gfp_t flags) > > > { > > > enum zone_type z; > > > - int bit = (__force int) (flags & GFP_ZONEMASK); > > > + z = ((__force unsigned int)flags & ___GFP_ZONE_MASK) ^ ZONE_NORMAL; > > > + > > > + if (z > OPT_ZONE_HIGHMEM) > > > + z = OPT_ZONE_HIGHMEM + > > > + !!((__force unsigned int)flags & ___GFP_MOVABLE); > > > > > > - z = (GFP_ZONE_TABLE >> (bit * GFP_ZONES_SHIFT)) & > > > - ((1 << GFP_ZONES_SHIFT) - 1); > > > - VM_BUG_ON((GFP_ZONE_BAD >> bit) & 1); > > > + VM_BUG_ON(z > ZONE_MOVABLE); > > > return z; > > > } > ^ permalink raw reply [flat|nested] 7+ messages in thread
* RE: [External] Re: [PATCH v1] include/linux/gfp.h: getting rid of GFP_ZONE_TABLE/BAD 2018-05-11 13:26 ` Matthew Wilcox @ 2018-05-12 11:35 ` Huaisheng HS1 Ye 2018-05-12 14:22 ` Matthew Wilcox 2018-05-18 3:03 ` Huaisheng HS1 Ye 1 sibling, 1 reply; 7+ messages in thread From: Huaisheng HS1 Ye @ 2018-05-12 11:35 UTC (permalink / raw) To: Matthew Wilcox Cc: akpm, linux-mm, mhocko, vbabka, mgorman, alexander.levin, colyli, NingTing Cheng, linux-kernel > From: Matthew Wilcox [mailto:willy@infradead.org] > Sent: Friday, May 11, 2018 9:26 PM> > On Fri, May 11, 2018 at 03:24:34AM +0000, Huaisheng HS1 Ye wrote: > > > From: owner-linux-mm@kvack.org [mailto:owner-linux-mm@kvack.org] On Behalf Of > Matthew > > > Wilcox > > > On Fri, May 11, 2018 at 12:10:25AM +0800, Huaisheng Ye wrote: > > > > -#define __GFP_DMA ((__force gfp_t)___GFP_DMA) > > > > -#define __GFP_HIGHMEM ((__force gfp_t)___GFP_HIGHMEM) > > > > -#define __GFP_DMA32 ((__force gfp_t)___GFP_DMA32) > > > > +#define __GFP_DMA ((__force gfp_t)OPT_ZONE_DMA ^ ZONE_NORMAL) > > > > +#define __GFP_HIGHMEM ((__force gfp_t)ZONE_MOVABLE ^ ZONE_NORMAL) > > > > +#define __GFP_DMA32 ((__force gfp_t)OPT_ZONE_DMA32 ^ ZONE_NORMAL) > > > > > > No, you've made gfp_zone even more complex than it already is. > > > If you can't use OPT_ZONE_HIGHMEM here, then this is a waste of time. > > > > > Dear Matthew, > > > > The reason why I don't use OPT_ZONE_HIGHMEM for __GFP_HIGHMEM directly is that, > for x86_64 platform there is no CONFIG_HIGHMEM, so OPT_ZONE_HIGHMEM shall always be > equal to ZONE_NORMAL. > > Right. On 64-bit platforms, if somebody asks for HIGHMEM, they should > get NORMAL pages. > > > For gfp_zone it is impossible to distinguish the meaning of lowest 3 bits in flags. > How can gfp_zone to understand it comes from OPT_ZONE_HIGHMEM or ZONE_NORMAL? > > And the most pained thing is that, if __GFP_HIGHMEM with movable flag enabled, it > means that ZONE_MOVABLE shall be returned. > > That is different from ZONE_DMA, ZONE_DMA32 and ZONE_NORMAL. > > The point of this exercise is to actually encode the zone number in > the bottom bits of the GFP flags instead of something which has to be > interpreted into a zone number. When somebody sets __GFP_MOVABLE, they > should also be setting ZONE_MOVABLE: > > -#define __GFP_MOVABLE ((__force gfp_t)___GFP_MOVABLE) /* ZONE_MOVABLE allowed */ > +#define __GFP_MOVABLE ((__force gfp_t)(___GFP_MOVABLE | (ZONE_MOVABLE ^ ZONE_NORMAL))) > I am afraid we couldn't do that, because __GFP_MOVABLE would be used potentially with other __GFPs like __GFP_DMA and __GFP_DMA32. Let's go back to the previous example. We assume ZONE_DMA equals to 0, and ZONE_DMA32 equals to 1. After encoding with ZONE_NORMAL (which equals to 2), we could get that. #define __GFP_DMA ((__force gfp_t)OPT_ZONE_DMA ^ ZONE_NORMAL) #define __GFP_DMA32 ((__force gfp_t)OPT_ZONE_DMA32 ^ ZONE_NORMAL) __GPF_DMA = 0b 0010 __GPF_DMA32 = 0b 0011 We assume ZONE_MOVABLE equals to 3, #define __GFP_MOVABLE ((__force gfp_t)(___GFP_MOVABLE | (ZONE_MOVABLE ^ ZONE_NORMAL))) __GFP_MOVABLE = 0b 1001 If we OR'ing __GFP_MOVABLE and either __GFP_DMA or __GFP_DMA32, we could get same result as '0b 1011'. This is unacceptable, because inline function gfp_zone couldn't distinguish that is a request of ZONE_DMA or ZONE_DMA32 from parameter flags. Once more, I think if we want to encode ZONE_MOVABLE to __GFP_MOVABLE, then the operation of __GFP_MOVABLE OR'ing with any other __GFP* would have risk. Sincerely, Huaisheng Ye > One thing that does need to change is: > > -#define GFP_HIGHUSER_MOVABLE (GFP_HIGHUSER | __GFP_MOVABLE) > +#define GFP_HIGHUSER_MOVABLE (GFP_USER | __GFP_MOVABLE) > > otherwise we'll be OR'ing ZONE_MOVABLE and ZONE_HIGHMEM together. > > > I was thinking... > > Whether it is possible to use other judgement condition to decide OPT_ZONE_HIGHMEM > or ZONE_MOVABLE shall be returned from gfp_zone. > > > > Sincerely, > > Huaisheng Ye > > > > > > > > static inline enum zone_type gfp_zone(gfp_t flags) > > > > { > > > > enum zone_type z; > > > > - int bit = (__force int) (flags & GFP_ZONEMASK); > > > > + z = ((__force unsigned int)flags & ___GFP_ZONE_MASK) ^ ZONE_NORMAL; > > > > + > > > > + if (z > OPT_ZONE_HIGHMEM) > > > > + z = OPT_ZONE_HIGHMEM + > > > > + !!((__force unsigned int)flags & ___GFP_MOVABLE); > > > > > > > > - z = (GFP_ZONE_TABLE >> (bit * GFP_ZONES_SHIFT)) & > > > > - ((1 << GFP_ZONES_SHIFT) - 1); > > > > - VM_BUG_ON((GFP_ZONE_BAD >> bit) & 1); > > > > + VM_BUG_ON(z > ZONE_MOVABLE); > > > > return z; > > > > } > > ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [External] Re: [PATCH v1] include/linux/gfp.h: getting rid of GFP_ZONE_TABLE/BAD 2018-05-12 11:35 ` Huaisheng HS1 Ye @ 2018-05-12 14:22 ` Matthew Wilcox 2018-05-16 12:12 ` Huaisheng HS1 Ye 0 siblings, 1 reply; 7+ messages in thread From: Matthew Wilcox @ 2018-05-12 14:22 UTC (permalink / raw) To: Huaisheng HS1 Ye Cc: akpm, linux-mm, mhocko, vbabka, mgorman, alexander.levin, colyli, NingTing Cheng, linux-kernel On Sat, May 12, 2018 at 11:35:00AM +0000, Huaisheng HS1 Ye wrote: > > The point of this exercise is to actually encode the zone number in > > the bottom bits of the GFP flags instead of something which has to be > > interpreted into a zone number. When somebody sets __GFP_MOVABLE, they > > should also be setting ZONE_MOVABLE: > > > > -#define __GFP_MOVABLE ((__force gfp_t)___GFP_MOVABLE) /* ZONE_MOVABLE allowed */ > > +#define __GFP_MOVABLE ((__force gfp_t)(___GFP_MOVABLE | (ZONE_MOVABLE ^ ZONE_NORMAL))) > > > I am afraid we couldn't do that, because __GFP_MOVABLE would be used potentially with other __GFPs like __GFP_DMA and __GFP_DMA32. That's not a combination that makes much sense. I know it's permitted today (and it has the effect of being a no-op), but when you think about it, it doesn't actually make any sense. ^ permalink raw reply [flat|nested] 7+ messages in thread
* RE: [External] Re: [PATCH v1] include/linux/gfp.h: getting rid of GFP_ZONE_TABLE/BAD 2018-05-12 14:22 ` Matthew Wilcox @ 2018-05-16 12:12 ` Huaisheng HS1 Ye 0 siblings, 0 replies; 7+ messages in thread From: Huaisheng HS1 Ye @ 2018-05-16 12:12 UTC (permalink / raw) To: Matthew Wilcox Cc: akpm, linux-mm, mhocko, vbabka, mgorman, alexander.levin, colyli, NingTing Cheng, linux-kernel > From: Matthew Wilcox [mailto:willy@infradead.org] > Sent: Saturday, May 12, 2018 10:23 PM> > On Sat, May 12, 2018 at 11:35:00AM +0000, Huaisheng HS1 Ye wrote: > > > The point of this exercise is to actually encode the zone number in > > > the bottom bits of the GFP flags instead of something which has to be > > > interpreted into a zone number. When somebody sets __GFP_MOVABLE, they > > > should also be setting ZONE_MOVABLE: > > > > > > -#define __GFP_MOVABLE ((__force gfp_t)___GFP_MOVABLE) /* ZONE_MOVABLE allowed > */ > > > +#define __GFP_MOVABLE ((__force gfp_t)(___GFP_MOVABLE | (ZONE_MOVABLE ^ > ZONE_NORMAL))) > > > > > I am afraid we couldn't do that, because __GFP_MOVABLE would be used potentially > with other __GFPs like __GFP_DMA and __GFP_DMA32. > > That's not a combination that makes much sense. I know it's permitted today > (and it has the effect of being a no-op), but when you think about it, it > doesn't actually make any sense. Yes, you are right. After checking almost all references of __GFP_MOVABLE and other __GFP_* flags, perhaps I was far to get excessive pursuit of logical correctness. For those nonsense combinations, I should ignore them. Current GFP_ZONE_TABLE can ensure all logical correctness. That makes me want to pursue same effect. Next, I will revise the patch according to your advice, then try to get overall testing result as far as possible. There are many combinations because of a lot of conditions in file system and drivers. Hope I could test all things related to the lower 4 bits of gfp. Sincerely, Huaisheng Ye ^ permalink raw reply [flat|nested] 7+ messages in thread
* RE: [External] Re: [PATCH v1] include/linux/gfp.h: getting rid of GFP_ZONE_TABLE/BAD 2018-05-11 13:26 ` Matthew Wilcox 2018-05-12 11:35 ` Huaisheng HS1 Ye @ 2018-05-18 3:03 ` Huaisheng HS1 Ye 1 sibling, 0 replies; 7+ messages in thread From: Huaisheng HS1 Ye @ 2018-05-18 3:03 UTC (permalink / raw) To: Matthew Wilcox Cc: akpm, linux-mm, mhocko, vbabka, mgorman, alexander.levin, colyli, NingTing Cheng, linux-kernel > From: Matthew Wilcox [mailto:willy@infradead.org] > Sent: Friday, May 11, 2018 9:26 PM > On Fri, May 11, 2018 at 03:24:34AM +0000, Huaisheng HS1 Ye wrote: > > > From: owner-linux-mm@kvack.org [mailto:owner-linux-mm@kvack.org] On Behalf Of > Matthew > > > Wilcox > > > On Fri, May 11, 2018 at 12:10:25AM +0800, Huaisheng Ye wrote: > > > > -#define __GFP_DMA ((__force gfp_t)___GFP_DMA) > > > > -#define __GFP_HIGHMEM ((__force gfp_t)___GFP_HIGHMEM) > > > > -#define __GFP_DMA32 ((__force gfp_t)___GFP_DMA32) > > > > +#define __GFP_DMA ((__force gfp_t)OPT_ZONE_DMA ^ ZONE_NORMAL) > > > > +#define __GFP_HIGHMEM ((__force gfp_t)ZONE_MOVABLE ^ ZONE_NORMAL) > > > > +#define __GFP_DMA32 ((__force gfp_t)OPT_ZONE_DMA32 ^ ZONE_NORMAL) > > > > > > No, you've made gfp_zone even more complex than it already is. > > > If you can't use OPT_ZONE_HIGHMEM here, then this is a waste of time. > > > > > Dear Matthew, > > > > The reason why I don't use OPT_ZONE_HIGHMEM for __GFP_HIGHMEM directly is that, > for x86_64 platform there is no CONFIG_HIGHMEM, so OPT_ZONE_HIGHMEM shall always be > equal to ZONE_NORMAL. > > Right. On 64-bit platforms, if somebody asks for HIGHMEM, they should > get NORMAL pages. > > > For gfp_zone it is impossible to distinguish the meaning of lowest 3 bits in flags. > How can gfp_zone to understand it comes from OPT_ZONE_HIGHMEM or ZONE_NORMAL? > > And the most pained thing is that, if __GFP_HIGHMEM with movable flag enabled, it > means that ZONE_MOVABLE shall be returned. > > That is different from ZONE_DMA, ZONE_DMA32 and ZONE_NORMAL. > > The point of this exercise is to actually encode the zone number in > the bottom bits of the GFP flags instead of something which has to be > interpreted into a zone number. When somebody sets __GFP_MOVABLE, they > should also be setting ZONE_MOVABLE: > > -#define __GFP_MOVABLE ((__force gfp_t)___GFP_MOVABLE) /* ZONE_MOVABLE allowed */ > +#define __GFP_MOVABLE ((__force gfp_t)(___GFP_MOVABLE | (ZONE_MOVABLE ^ ZONE_NORMAL))) > > One thing that does need to change is: > > -#define GFP_HIGHUSER_MOVABLE (GFP_HIGHUSER | __GFP_MOVABLE) > +#define GFP_HIGHUSER_MOVABLE (GFP_USER | __GFP_MOVABLE) > > otherwise we'll be OR'ing ZONE_MOVABLE and ZONE_HIGHMEM together. Dear Matthew, After thinking it over and over, I am afraid there is something needs to be discussed here. You know current X86_64 config file of kernel doesn't enable CONFIG_HIGHMEM, that is to say from this below, #define __GFP_HIGHMEM ((__force gfp_t)OPT_ZONE_HIGHMEM ^ ZONE_NORMAL) __GFP_HIGHMEM should equal to 0b0000, same as the value of ZONE_NORMAL gets encoded. If we define __GFP_MOVABLE like this, #define __GFP_MOVABLE ((__force gfp_t)(___GFP_MOVABLE | (ZONE_MOVABLE ^ ZONE_NORMAL))) Just like your introduced before, with this modification when somebody sets __GFP_MOVABLE, they should also be setting ZONE_MOVABLE. That brings us a problem, current mm (GFP_ZONE_TABLE) treats __GFP_MOVABLE as ZONE_NORMAL with movable policy, if without __GFP_HIGHMEM. The mm shall allocate a page or pages from migrate movable list of ZONE_NORMAL's freelist. So that conflicts with this modification. And I have checked current kernel, some of function directly set parameter gfp like this. For example, in fs/ext4/extents.c __read_extent_tree_block, bh = sb_getblk_gfp(inode->i_sb, pblk, __GFP_MOVABLE | GFP_NOFS); for these situations, I think only modify GFP_HIGHUSER_MOVABLE is not enough. I am preparing a workaround to solve this in the V2 patch. Later I will upload it to email loop. Sincerely, Huaisheng Ye > > I was thinking... > > Whether it is possible to use other judgement condition to decide OPT_ZONE_HIGHMEM > or ZONE_MOVABLE shall be returned from gfp_zone. > > > > Sincerely, > > Huaisheng Ye > > > > > > > > static inline enum zone_type gfp_zone(gfp_t flags) > > > > { > > > > enum zone_type z; > > > > - int bit = (__force int) (flags & GFP_ZONEMASK); > > > > + z = ((__force unsigned int)flags & ___GFP_ZONE_MASK) ^ ZONE_NORMAL; > > > > + > > > > + if (z > OPT_ZONE_HIGHMEM) > > > > + z = OPT_ZONE_HIGHMEM + > > > > + !!((__force unsigned int)flags & ___GFP_MOVABLE); > > > > > > > > - z = (GFP_ZONE_TABLE >> (bit * GFP_ZONES_SHIFT)) & > > > > - ((1 << GFP_ZONES_SHIFT) - 1); > > > > - VM_BUG_ON((GFP_ZONE_BAD >> bit) & 1); > > > > + VM_BUG_ON(z > ZONE_MOVABLE); > > > > return z; > > > > } > > ^ permalink raw reply [flat|nested] 7+ messages in thread
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[not found] <1525968625-40825-1-git-send-email-yehs1@lenovo.com>
2018-05-10 16:30 ` [PATCH v1] include/linux/gfp.h: getting rid of GFP_ZONE_TABLE/BAD Matthew Wilcox
2018-05-11 3:24 ` [External] " Huaisheng HS1 Ye
2018-05-11 13:26 ` Matthew Wilcox
2018-05-12 11:35 ` Huaisheng HS1 Ye
2018-05-12 14:22 ` Matthew Wilcox
2018-05-16 12:12 ` Huaisheng HS1 Ye
2018-05-18 3:03 ` Huaisheng HS1 Ye
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