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bangkok:set mmap readahead upbound limitation

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vdex/odex file mmap operation actually does random access, the large
read ahead size can harm the performance, use this configuration to
limit the uplimit of read ahead cache size

Change-Id: Ic370e9372803e538b247b69501875018afeba32e
Signed-off-by: wangwang <wangwang@motorola.com>
Reviewed-on: https://gerrit.mot.com/2650468
SME-Granted: SME Approvals Granted
SLTApproved: Slta Waiver
Tested-by: Jira Key
Reviewed-by: Xiangpo Zhao <zhaoxp3@motorola.com>
Submit-Approved: Jira Key
This commit is contained in:
wangwang 2023-06-21 12:21:19 +08:00 • committed by Xiaojun Ji
commit 6a8ae96b36
2 changed files with 21 additions and 3 deletions
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7
mm/Kconfig
View file

@ -736,6 +736,13 @@ config DEVICE_PRIVATE
memory; i.e., memory that is only accessible from the device (or
group of devices). You likely also want to select HMM_MIRROR.
config MMAP_READAROUND_LIMIT
int "Limit mmap readaround upperbond"
default 0
help
Inappropriate mmap readaround size can hurt device performance
during the sluggish situation. Add the hard upper-limit for
mmap readaround
config FRAME_VECTOR
bool

17
mm/filemap.c
View file

@ -2560,6 +2560,7 @@ static struct file *do_sync_mmap_readahead(struct vm_fault *vmf)
struct address_space *mapping = file->f_mapping;
struct file *fpin = NULL;
pgoff_t offset = vmf->pgoff;
unsigned int ra_pages;
/* If we don't want any read-ahead, don't bother */
if (vmf->vma_flags & VM_RAND_READ)
@ -2588,10 +2589,20 @@ static struct file *do_sync_mmap_readahead(struct vm_fault *vmf)
/*
* mmap read-around
*/
#if CONFIG_MMAP_READAROUND_LIMIT == 0
ra_pages = ra->ra_pages;
#else
if (ra->ra_pages > CONFIG_MMAP_READAROUND_LIMIT)
ra_pages = CONFIG_MMAP_READAROUND_LIMIT < 0 ? 0 : CONFIG_MMAP_READAROUND_LIMIT;
else
ra_pages = ra->ra_pages;
#endif
fpin = maybe_unlock_mmap_for_io(vmf, fpin);
ra->start = max_t(long, 0, offset - ra->ra_pages / 2);
ra->size = ra->ra_pages;
ra->async_size = ra->ra_pages / 4;
ra->start = max_t(long, 0, offset - ra_pages / 2);
ra->size = ra_pages;
ra->async_size = ra_pages / 4;
ra_submit(ra, mapping, file);
return fpin;
}