Messages in this thread | | | Date | Wed, 10 Aug 2022 09:33:26 +0800 | Subject | Re: [PATCH v5] mm/page_owner.c: add llseek for page_owner | From | Kassey Li <> |
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On 8/9/2022 5:30 PM, Vlastimil Babka (SUSE) wrote: > On 8/9/22 04:47, Kassey Li wrote: >> There is usage to dump a given cma region page_owner >> instead of all page's. >> >> This change allows to specify a ppos as start_pfn >> by fseek. >> >> Any invalid ppos will be skipped, so it did not >> broken the origin dump feature. >> >> Suggested-by: Vlastimil Babka <vbabka@suse.cz> >> Signed-off-by: Kassey Li <quic_yingangl@quicinc.com> >> --- >> Documentation/vm/page_owner.rst | 6 ++++++ >> mm/internal.h | 5 +++++ >> mm/page_owner.c | 9 ++++++--- >> 3 files changed, 17 insertions(+), 3 deletions(-) >> >> diff --git a/Documentation/vm/page_owner.rst b/Documentation/vm/page_owner.rst >> index f5c954afe97c..8d33d976da8a 100644 >> --- a/Documentation/vm/page_owner.rst >> +++ b/Documentation/vm/page_owner.rst >> @@ -95,6 +95,12 @@ Usage >> PFN XXX ... >> // Detailed stack >> >> + By default, it will do full pfn dump, to start with a given pfn, >> + page_owner supports fseek. >> + >> + FILE *fp = fopen("/sys/kernel/debug/page_owner", "r"); >> + fseek(fp, pfn_start, SEEK_SET); >> + >> The ``page_owner_sort`` tool ignores ``PFN`` rows, puts the remaining rows >> in buf, uses regexp to extract the page order value, counts the times >> and pages of buf, and finally sorts them according to the parameter(s). >> diff --git a/mm/internal.h b/mm/internal.h >> index c0f8fbe0445b..1ad8f86e6e33 100644 >> --- a/mm/internal.h >> +++ b/mm/internal.h >> @@ -189,6 +189,11 @@ extern void reclaim_throttle(pg_data_t *pgdat, enum vmscan_throttle_state reason >> */ >> extern pmd_t *mm_find_pmd(struct mm_struct *mm, unsigned long address); >> >> +/* >> + * in mm/page_owner.c: > > This should say where it's defined, not used from, and that's > fs/proc/base.c. But it's already declared in fs/proc/internal.h so maybe > page_owner.c could just include that header (although it's a bit meh). ok, let's do it. > >> + */ >> +extern loff_t mem_lseek(struct file *, loff_t, int); >> + >> /* >> * in mm/page_alloc.c >> */ >> diff --git a/mm/page_owner.c b/mm/page_owner.c >> index e4c6f3f1695b..dcbe05e206e1 100644 >> --- a/mm/page_owner.c >> +++ b/mm/page_owner.c >> @@ -497,8 +497,10 @@ read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos) >> return -EINVAL; >> >> page = NULL; >> - pfn = min_low_pfn + *ppos; >> - >> + if (*ppos == 0) >> + pfn= min_low_pfn; > > missing space before '='
my bad, for v6
./scripts/checkpatch.pl v6-0001-mm-page_owner.c-add-llseek-for-page_owner.patch total: 0 errors, 0 warnings, 46 lines checked
v6-0001-mm-page_owner.c-add-llseek-for-page_owner.patch has no obvious style problems and is ready for submission. > >> + else >> + pfn = *ppos; >> /* Find a valid PFN or the start of a MAX_ORDER_NR_PAGES area */ >> while (!pfn_valid(pfn) && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0) >> pfn++; >> @@ -561,7 +563,7 @@ read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos) >> continue; >> >> /* Record the next PFN to read in the file offset */ >> - *ppos = (pfn - min_low_pfn) + 1; >> + *ppos = pfn + 1; >> >> return print_page_owner(buf, count, pfn, page, >> page_owner, handle); >> @@ -660,6 +662,7 @@ static void init_early_allocated_pages(void) >> >> static const struct file_operations proc_page_owner_operations = { >> .read = read_page_owner, >> + .llseek = mem_lseek, >> }; >> >> static int __init pageowner_init(void) >
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